Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations

1963 Metal nitrate complexes with tributyl phosphate and with trioctyl phosphine oxide Eugene Warren Nadig Iowa State University

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NADIG, Eugene Warren, 1933- METAL NITRATE COMPLEXES WITH TRIBUTYL PHOSPHATE AND WITH TRIOCTYL PHOSPHINE OXIDE.

Iowa State University of Science and Technology Ph.D.. 1963 En§nîvefsi?f^Îvficroîiïms! Inc., Ann Arbor, Michigan METAL NITRATE COMPLEXES WITH TRIBUTYL PHOSPHATE AND WITH TRIOCTYL PHOSPHINE OXIDE

Eugene Warren Nadig

A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY

Major Subject: Chemical Engineering

Approved:

Signature was redacted for privacy. In 1 Work

Signature was redacted for privacy. Head of Major Department

Signature was redacted for privacy. Dean/of Graduate College

Iowa State University Of Science and Technology Ames, Iowa 1963 il

TABLE OF CONTENTS Page SUMMARY iv INTRODUCTION 1 PRINCIPLES OF INFRARED SPECTRA 4 PREVIOUS WORK 9 Tributyl Phosphate 9 Tri-n-octyl Phosphine Oxide 15 PROCEDURE 17 RESULTS 20 Tributyl Phosphate, , Water System 20 Tributyl Phosphate, Salt, Nitric Acid System 23 Tributyl Phosphate, Nitrate, Nitric Acid System 29 Tributyl Phosphate, Rare Earth Nitrate, Nitric Acid Systems 32 Tributyl Phosphate, Ferric Salt Systems 40 Tributyl Phosphate, Divalent Salt Systems 40 Tri-n-octyl Phosphine Oxide, Uranyl Salt Systems 42 Tri-n-octyl Phosphine Oxide, Various Salt Systems 45 Methyl Isoamyl Ketone, Salt Systems 46 HDPM, System 48 Tri-n-octyl Amine, Uranyl Nitrate System 49 iii

Page DISCUSSION OF RESULTS 51 General Comments 51 Spatial Configuration 52 P —> 0 Shift 53 Covalency of the Solute 62 General Extraction Theory • 66 ACKNOWLEDGMENTS 71 BIBLIOGRAPHY 72 APPENDIX 78 iv

SUMMARY

An infrared spectra investigation of organic containing various inorganic solutes was made. The emphasis was on metal nitrate complexes with tributyl phosphate and with tri-n-octyl phosphine oxide. The infrared spectra indicated that in all solute- systems studied a single complex was formed with the attachment of the solute taking place at the phosphoryl oxygen in the case of tributyl phosphate and tri-n-octyl phosphine oxide. There was no indication of an attachment to the oxygen of the P-O-C group in the case of tributyl phosphate. Empirical studies indicated that most nitrates were of the Cgy symmetry type with the nitrato group covalently bound through one oxygen atom to the metal. The presence of vjj, in the region 1481 - 1531 cm~l and in the region 1290 - 1253 cm~l indicated the following structure for nitrate solutes: /0 m—0—NCT 0 Spectra of all soluble nitrates in the organic phase run by the author showed and bands. A linear correlation was obtained between the ionic potential (charge of cation/ionic radius of cation) of a solute in tributyl phosphate and the P —> 0 frequency shift. V

A different linear correlation was found for solutes in tri-n-octyl phosphine oxide. It would be expected that the. higher the ionic potential of the solute, the stronger the bond formed between it and the solvent. From theoretical considerations the shift is interpreted as indicative of the strength of the complex formed, possibly quantitatively. Thus, the correlation of P —> 0 shift and ionic potential is con­ sistent with these viewpoints. A linear relation between P —> 0 frequency shift and the covalency of the solute, measured by the frequency differ­ ence v/j, - Vi, was found for tributyl phosphate. A different linear relationship was obtained for tri-n-octyl phosphine oxide. These correlations are consistent with the fact that the ionic potential, which correlates with P —> 0 shift, is directly related to the amount of covalence in a compound. If covalence is defined as the resistance to ionization or the sharing of electrons, one would expect that a high charge on the cation of a solute and a small radius would bring it closer to the anion and thus form a stronger and more covalent bond due to the overlapping of orbitals. For tributyl phosphate an essentially linear relation exists between the P —> 0 stretch frequency shift and the grams of extractable species per 100 grams of complex with two exceptions: ferric chloride and ferric nitrate. Grams of extractable species per 100 grams of complex can be vi represented as

100 mj

m]_ + ui2 where = the molecular weight of the solute and m^ = the molecular weight of tributyl phosphate multiplied by the number of tributyl phosphate molecules attached to the metal in the complex. This relationship apparently represents a reasonably reliable means of estimating the number of tributyl phosphate molecules in the complex. For tri-n-octyl phosphine oxide the correlation of grams of extractable species per 100 grams of complex or 100 m^ / m^_ + m^ versus P —> 0 stretch frequency shift was apparently not as good as that for tributyl phosphate. The maximum distribution coefficient of a nitrate between tributyl phosphate and the aqueous phase was found to be related to both the ionic potential of the cation and grams of extractable species per 100 grams of complex. The correla­ tions were made for the tributyl phosphate-nitric acid-metal nitrate system because of the availability of data for the maximum distribution coefficients. 1

INTRODUCTION

In spite of the fact that solvent extraction has been widely used in recent years, especially in making difficult separations in the atomic energy program, little is known of the fundamental chemistry involved in even the simplest systems. The selection of a solvent for a given application is largely a trial-and-error procedure and much data must be obtained in the laboratory to determine the equilibrium relationships. The examination of infrared spectra represents one approach to the investigation of complexes formed between a solvent and an extractable salt of a metal. In conjunction with similar studies using nuclear magnetic resonance, ultra­ violet spectra, visible spectra, cetera,, a knowledge of infrared spectra should lead to a better understanding of the chemistry involved in the extraction process. The initial objective of this research was to determine the effect of solute concentration on the infrared spectra of the solute in the solvent. Bostian (9) had investigated the infrared spectra of various concentrations of neodymium nitrate in tributyl phosphate and this research was intended to be an extension of his work to other systems. After a few systems had been studied it was found that a change in concentration caused only a change in intensity of 2 a few bands, rather than a change in the frequencies. The direction of the research was then changed to a study of the effect of the solute on certain frequencies appearing in the infrared spectrum of the solute-solvent system. Solvents saturated, or nearly saturated, with the particular solute under study were used throughout the remainder of the research. The solvents used were tributyl phosphate (TBP), tri- n-octyl phosphine oxide (TOPO), methyl isoamyl ketone (MIAK), hexone (MIBK), bis (di-n-hexylphosphinyl) methane (HDPM), and tri-n-octyl amine (TOA). Because there is currently much interest in tributyl phosphate and tri-n-octyl phosphine oxide at this laboratory, as well as elsewhere, emphasis was given to these two solvents. Also, the nature of the spectra made the use of these two solvents particularly desirable. Although a wide variety of metal salts were used, most were metal nitrates and the major interest was metal nitrate complexes with tributyl phosphate and tri-n-octyl phosphine oxide. The desirable physical properties of tributyl phosphate are well known and are given by McKay and Healy (37)- Tri-n-octyl phosphine oxide has not been used or studied as extensively as has tributyl phosphate. It is a solid at room temperature melting at 51 - 52 °C. It is, however, soluble in most hydrocarbons at room temperature and 3 highly resistant to oxidation and is considered to be the most stable of the organo-phosphorus family. It is now commercially available in pure form in both the United States and Great Britain. 4

PRINCIPLES OF INFRARED SPECTRA

Some direct relation might be expected to exist between the motions of the atoms within molecules and their effects on infrared radiation incident upon them. Spectroscopy is concerned with the interaction of matter and electromagnetic radiation in which energy is taken from or added to the radia­ tion field. In getting infrared spectra of samples, the former is involved. When radiation passes through any homogeneous transparent medium it emerges diminished in energy. An absorbing medium between the light source and the receiving medium absorbs light of certain wave lengths or frequencies. A spectrum is a plot of the relative amounts of radiant energy absorbed or emitted at each frequency. Usually spectra show a plot of percentage transmission versus frequency and wave length, in which case the regions of strongest absorption appear on the curve as minima. Before measurements of the intensity or amount of radiation absorbed at various wave lengths can be made, the infrared beam that has been passed through the test substance must be broken up into different wave lengths and arranged in numerical sequence. Measurement of the intensity is most often accomplished by measuring the heat effect. By rotation of a Littrow mirror, different wave lengths of the dispersed 5 beam are directed to the energy receiver, where the intensity of each is measured by a thermocouple and recorded by a potentiometer. For a more detailed description of an infrared spectrometer see Bauman (5). Any nonlinear polyatomic molecule with n atoms has 311-6 degrees of freedom. Corresponding to these are 3*1-6 normal modes of vibration, each with a definite vibration frequency (5,22). For instance, the nitrate ion would vibrate at (3x4 -6=6) six vibrational frequencies. Any frequency observed in the infrared spectrum of any molecule must either be one of these fundamental frequencies, or a multiple or combination of them. When a molecule absorbs infrared radiation, the atoms are set in vibratory motions, depending upon their masses and binding forces. Each type of vibration requires a certain amount of energy, which is extracted from the light source and is made evident in the absorption spectrum. A chemical bond exists between two or more atoms when the forces acting between them are of sufficient strength that the group behaves as an independent atomic aggregate. The energy necessary to break the bond is called the bond strength. Any given type of bond will absorb energy of a characteristic frequency, but this frequency will be altered slightly, depending upon what other types of atoms are attached to the atoms of the bond. Since each atom may vibrate in different 6 directions, any one type of bond may absorb light energy at two or more different frequencies. Whenever a particular group, if separated from the rest of the molecule, has a vibrational frequency that differs sufficiently from any vibrational frequency of the rest of the molecule, then this frequency will occur only slightly changed in the whole molecule and will roughly correspond to vibrational motions in that group. Such a frequency is called a characteristic frequency of the group (5). The frequency of an absorption band, the band intensity, and the contour of the band are valuable clues to the nature of the species responsible for the absorption. For instance, the depth of the band of a bond is dependent upon the concentration of the bond. The relationship is given by the well-known Beer's law which states that for a given sample thickness the transmittance depends exponentially on the concentration of the absorbing species. This relationship is

io logio Y ~ Ecl where Iq is the incident intensity; I the intensity that will pass through a sample of thickness t; c is the concentration of the absorbing species, and E a constant. Infrared absorption bands are observable when there are changes in the dipole moment of a molecule due to the 7 vibration of its component atoms. Vibrational and rotational motions involving atoms themselves are associated with the near infrared i.e. 1 - 20 microns (p.). Bands in the near infrared spectrum may, in general, be ascribed to relative vibration of two adjacent parts of a molecule. Such vibrations may be along the lines joining the adjacent parts or perpendic­ ular to the above lines. The first type are the stretching vibrations while the second type are the bending vibrations which, in general, give rise to smaller restoring forces, and therefore smaller frequencies. Rotational energy differences are small compared with the vibrational, and the result is a cluster of lines in the absorption spectrum, the center of which corresponds to the pure vibrational transition. This is one reason that the motions of atoms in molecules give rise to bands (5)• For molecules, the largest totally symmetric frequency is called V]_, the second largest Vg, and so on. If there are f such vibrations, the largest frequency of the next species in the molecule is called vf+]_> and so forth (22). Only one exception to this rule is made. In the case of linear XÏ£ and XYZ molecules the perpendicular vibration is always called Vg in agreement with a long established custom. In infrared spectroscopy the symmetry of a crystal or molecule is of importance. Two groups of symmetry are of interest here. In the first group are those whose symmetry 8 consists of a single symmetry axis and denoted by the letter C. The degree of the axis is added as a suffix. If a molecule has a p-fold axis Gp (rotation of the molecule about this axis through an angle of ^9° results in an equivalent molecular position) and p planes of symmetry CTv through the axis, it belongs to the point group Cpv. The planes through the axis are vertical planes. It is always assumed that an axis of symmetry, if only one is present, is set up vertically.

That is why the planes are called cry. The p planes are symmetrically arranged at angles 360°/2p. In the second group are those whose symmetry can be represented as arising from the addition of n twofold axes to one n-fold "principal axis.11 These are distinguished by the capital letter D, to which is added as a suffix the degree of the principal axis. A crystal of class D^, for example, has a threefold axis and three twofold axes of symmetry. The twofold axes lie all in one horizontal plane at right angles to the threefold axis and they intersect one another at angles of 120° in a point lying on the threefold axis. For a more detailed account of symmetry properties of molecules see Herzberg (22). 9

PREVIOUS WORK

Tributyl Phosphate

Tributyl phosphate [(C^H^O)^PO] is a good solvent because of the donor nature of the phosphoryl oxygen. The bond between the phosphorus and oxygen in the tributyl phosphate molecule is semipolar. The notation is (C^H^O)^P —> 0. This has been determined from ultraviolet spectra (2), dipole moments (28), parachors (51), and bond refractions (19). The extraction of nitrates by tributyl phosphate has been extensively studied (1,8,9»14,20,21,23,24,2?,33,34,37»41, 42,43,44,45,47»48,49j54) as well as some work with other anions. McKay and Healy (37) have proposed that in the extraction of trivalent lanthanide cations a trisolvate is formed, M(NO^)y 3TBP; for tetravalent cations, i.e. Th(IV), Np(IV), Pu(IV), a disolvate is formed, M(NO^)^«2TBP; and for hexavalent actinide cations, UO^(II), NpOgdl), PuO^(Ii), a similar disolvate is formed, MO^(NO^)^'2TBP. In general the tributyl phosphate dilution experiments indicated the following solvates (20,37): HNOy TBP, LiNOy2TBP, NaN0y3TBP, Ca(NO^'3TBP, (Y, Ce, Pm, Eu, Tb, Tm, Lu, Am)(NO^

•3TBP, (Zr, Th, Np, Pu)(NO^* 2TBP, and (U, Np, Pu)02-2TBP. By the method of Hesford and McKay (23), the number of solvent molecules attached to the solute is obtained from a 10 graph of the logarithm of the distribution coefficient plotted against the logarithm of the concentration of the solvent in an organic diluent. The slope of the line obtained indicates the number of solvent molecules attached to the extracted solute. This method cannot be used satisfactorily at high solvent concentrations because of non-ideality and solute- solvent interaction. Hesford and McKay (23) and Bostian (9) have proofs of why the slope method can be used. Infrared spectra of tributyl phosphate have been obtained by Bellamy and Beecher (7), Bostian (9), Gaunt and Meaburn (18), Kinney (33)» Nukada et al. (39), Peppard and Ferraro (43), and Norton and White (25)# Nukada al. (39) have made an infrared spectra study of the following: 1. Pure tributyl phosphate 2. The tributyl phosphate-water system. The P —> 0 stretch band shifted from 1280 cm"l to 1260 cra"^-. 3. The tributyl phosphate-nitric acid system. A series of nitric acid concentrations in five percent tributyl phosphate diluted with carbon tetrachloride were examined. The P —> 0 stretch complex band due to nitric acid was reported at 1208 cm"l. 4. The tributyl phosphate-uranyl nitrate system. The P —•> 0 stretch complex band due to uranyl nitrate was at 1187 cm~^. 5. The tributyl phosphate-uranyl nitrate-nitric acid system. 11

Two P —> 0 stretch complex bands were reported, one at 1228 cm"l for the TBP» HNO^ complex and the other at

1188 cm-1 for the UO2(NO^)2'2TBP complex. By varying the relative amounts of nitric acid and uranyl nitrate it was shown that a competitive extraction of both uranyl nitrate and nitric acid by tributyl phosphate takes place. Bostian (9) obtained infrared spectra of various concentrations of neodymium nitrate in tributyl phosphate up to saturation by contacting water equilibrated commercial grade solvent with aqueous solutions of neodymium nitrate. The P —> 0 absorption split into two separate bands as neodymium concentration increased, and one of the new absorp­ tion bands was shifted to a lower frequency. He concluded that the shift of the P —> 0 frequency indicated complexing with the rare earth nitrate because the intensity of the lower frequency band correlated with the concentration of neodymium nitrate. Katzin (31) obtained infrared spectra of the following solutes in tributyl phosphate: HgO, LiNOy3HgO, MgfNO^g*

6H20, Ca(N03)2'6H20, CoCl2.6H20, Co(N0^)2'6H20, Ni(N0o)2*

6H20, CuC12.6H20, Cu(N03)2-6H20, Zn(N0^)2'6Hg0, Cdlg,

Cd(N03)2»6H20, FeCly 6H20, Fe(NO^) y 9H20, Cr(NO ) -ÔHgO,

La(N03)3-6H20, Ce(N03)3-6H20, (NH^ )2Ce(N0 )g (HgO ),

U09C19(H90), U0_(N0_)^'6H^0, ThCl,,.XHo0 and Th(NO„),.« ^H„0. C. C. £. < J -- ~ '— J *+• C 12

The position of the P —> 0 stretch band was given for all the -solutes. No details were given in the article except that most of the solutions were made from hydrated crystalline salts, and at saturation were in equilibrium with a saturated aqueous phase. The author stated that mass of the entity attached to the phosphoryl oxygen was perhaps a factor in the magnitude of the shift of the P —> 0 stretch band, but comparison of say, cadmium nitrate with ferric nitrate, or ferric nitrate with thorium nitrate, indicated that this was not the determinative factor. Cationic charge and, presumably, nature and strength of the bond to the phosphoryl oxygen were factors to be considered also. Katzin (30) gave the results of the infrar&i spectra of some sixteen nitrates in tributyl phosphate. The splitting of the band of the nitrate ion was observed in particular. It was established that a splitting of about 100 cm~^ served as a defensible division between essentially electrostatic splitting and splitting due to co-ordinate binding. The instrument used was the Hilger double-beam infrared spectro­ photometer, model H800. Thin films of solution between plates of CaPg were used. A single plate of CaPg was used in the reference beam. Wavelength calibration was against the spectrum of a polystyrene film. The same experimental methods were probably used by Katzin in Reference Jl. Gatehouse al. (17) examined the infrared spectra 13 of a number of nitrato complexes of metals in the region.. between 4000 and ?00 crn""^. He made the assignments shown in Table 1, based on the spectrum of methyl nitrate (10), for complexes where the nitrato-group was covalently bound through one oxygen atom resulting in a lowering of the symmetry of the group to C2v.

Table 1. Infrared assignments for nitrates

Infrared 0N02 cm"l Assignment activity notation

Active Not observed N0 bending V3 2 Active V1 1290 - 1253 N02 symmetrical stretch Active v2 1034 - 970 N-0 stretch O O - H C O O r O O Active v6 1 Nonplanar rock

Active v4 1531 - 1481 N02 asymmetrical stretch

Active v5 Not observed Planar rock

Gatehouse sX- (17) distinguished between the covalently bonded nitrate group in these compounds and the free nitrate ion. The absorption frequencies for the NCy ion, which belongs to the point group (which includes all plane trigonally symmetric XY^ type molecules), were given by Herzberg (22) and are sViowm in Tab"1 e ?. 14

Table 2. Infrared assignments for nitrates

Infrared N(y- cm"-®- Assignment activity notation

Inactive V1 1050 N-0 stretching Active v2 831 NOg deformation Active v3 1390 NO2 asymmetrical stretch Active v4 720 Planar rocking

Strong absorption bands in the regions 1530 - 1481 cm""®* and 1290 - 1253 cm" ^ in metal compounds containing a N0^ group were indicative that the nitrato-group was coordinated to the metal atom through one oxygen (17). It should be noted that the and frequencies used by the author in the following sections are those with the notation in Table 1. Ferraro (15) presented the infrared spectra results of the tributyl phosphate complexes with La(^, Sm(NCy )^,

Se(NO^)^> Y(N0^)^, Ce(N0^)3, Th(NC^)* Ce(NO^)if,$ and UOgtNCy)g* For comparative purposes the spectra of the corresponding hydrates of the above nitrates were also examined. The article dealt mainly with values obtained from the spectra. The author took the difference between the and frequencies as a measure of the fM fi SVITIAf.r'V p v» "i Q i r> rr i n rii t;v»ofô rryr\tivs 15

Oshiraa (40) gave the results of the shift of the P —> 0 stretch band frequency and the V4 - frequency difference for several metal nitrates in tributyl phosphate. No experimental details were given. Ferraro (16) examined the infrared spectra of several metallic nitrates. He gave - v-^ values for many nitrates in the solid form. The A values (v^ - v-^) were seen to increase as one goes from monovalent metallic nitrates to tetravalent metallic nitrates, indicating greater polarization of the anion or increased covalent character in the metal-to- nitrate bond. The authors plotted ionic potential versus v4 ~ V1 (cm"l) for various metallic nitrates. The observation was made that in the nitrates where splitting occurs the separation of the and frequencies in the C2v type of symmetry were related to the ionic potential. Vratny (53) obtained the infrared spectra of 35 metal nitrates in the solid form and tabulated the various frequen­ cies. The compounds were classified as to the degree of ionic or covalent character.

Tri-n-octyl Phosphine Oxide

Most of the extraction data for solutes in tri-n-octyl phosphine oxide, (CgH^y )^P0, were given by White and Ross (56). They also determined the particular complexes involved between tri-n-octyl phosphine oxide and 16 various nitrates and chlorides using the slope method. Acidic solutions were used. Horton and White (25) published a spectrum of tri-n-octyl phosphine oxide. Horton and White (26) also recorded the infrared spectra of a number of adducts of tri-n-octyl phosphine oxide in order to obtain information concerning the type of bonding involved. The phosphoryl vibration disappeared from its normal position of 1143 cm"-®- for solid films of purified tri-n-octyl phosphine oxide. New, strong bands appeared at lower frequencies both for acid and metal adducts, indicating a radical shift of the former semicoordinate phosphoryl bond. Metals and their oxidation states studied included (IV) and (VI), molybdenum (VI), chromium (VI), thorium, zirconium, hafnium, cerium (IV), tin (IV), titanium (IV), gold, bismuth, and niobium (V). The spectra have not yet been published. No spectra of metal-tri-n-octyl phosphine oxide systems have been published although some probably have been obtained by various investigators in addition to Horton and White. 17

PROCEDURE

The infrared spectra of solutes in tributyl phosphate using servofrax (arsenic trisulfide) cells were obtained by either contacting the tributyl phosphate with a liquid aqueous phase containing the solute or dissolving the solute directly in the tributyl phosphate. The tributyl phosphate product was then used directly in obtaining the spectra. In the tables and figures, the term "nearly saturated" is used when the tributyl phosphate was contacted with a saturated aqueous solution, and the term "saturated" is used when the solute was dissolved directly in the tributyl phosphate to saturation. The infrared spectra of solutes in tributyl phosphate using sodium chloride cells were obtained by contacting 10 ml. of tributyl phosphate with about 10 ml. of a nearly saturated aqueous solution of a particular solute or dissolving the solute directly in the tributyl phosphate. In the tables and figures, the term "nearly saturated" is used for the former case, and the term "saturated" for the latter. Two ml. of the resulting organic phase were diluted to 10 ml. with carbon tetrachloride. Absorption by carbon tetrachloride was cancelled by use of a reference cell containing carbon tetrachloride.

The infrared spectra of solutes in tri-n-octyl phosphine 18 oxide using sodium chloride cells were obtained by contacting 10 ml. of 0.1 molar tri-n-octyl phosphine oxide in carbon tetrachloride with 10 ml. of a nearly saturated aqueous solution of the particular solute. The same method was used for uranyl nitrate in 0.1 molar HDPM in carbon tetrachloride and 15 percent tri-n-octyl amine in carbon tetrachloride. The infrared spectra of solutes in methyl isoamyl ketone were obtained by dissolving solid solutes into the solvent until saturated. All organic samples that were used with sodium chloride cells were dried with sodium sulfate to remove any excess water. Solid sodium chloride was added to remove any impurities which might react with the cell windows or stick to them. The tributyl phosphate used in these investigations was obtained from Fisher Scientific Company in purified form. The solutes which were used in the solid form had the follow­ ing hydrate formulas: U02(N03)2*6H20 , ThfNCy^'^HgO, Fe(NC>3)3'9H20, FeClyéHgO, CufNO^'S^O, CdfNO^Z'WigO,

Ca(N03)2.4H20, Zn(N03)2'6H20, ZrOfNO^g.XHgO, HfOfNOjg'XHgO,

SnCl^HzO, Co(N03)2'6H20, CoC12.6H20, and (NHj^CetNO-^.

XH20. The statements "sodium chloride cells" and "servofrax cells" were used throughout this thesis for brevity. The sodium chloride and servofrax refer to the windows of the cell. 19

Unless otherwise mentioned, all spectra were obtained on an automatic Perkin-Elmer Model 21 double beam spectro­ photometer, which directly registers frequency versus transmittance. The intensities for different compounds were not strictly comparable owing to the small differences in the thickness of the liquids used in the cells. Distilled water was used in all these experiments. 20

RESULTS

Tributyl Phosphate, Nitric Acid, Water System

Table 3 is a summary of data from the spectra of the tributyl phosphate and the tributyl phosphate-water systems.

Table 3* Spectra of tributyl phosphate and tributyl phosphate-water

Band Figure 10, Figure 11, Figure 12, purified TBP purified TBP purified TBP in NaCl cell in servofrax equilibrated wave number cell wave with water, (cm""l) number (cm~l) in servofrax cell wave number (cm"*-1-)

CH stretch 2980 2910 2910

CH2 stretch 2890 2880 2880 shoulder CHg bend 1468 1463 1463 CHo symmetrical 1380 1331 1381 bend

P —> 0 stretch 1275 1270 1260 P-O-C stretch 1028 1000 1000

Unknown 908 900 OK stretch 3480 OH bend 1640 21

For a sodium chloride cell the P —> 0 stretch band is actually a doublet so that the 1275 cm~l value represents the frequency of maximum intensity. For a servofrax cell, arsenic trisulfide, the P —> 0 stretch band for purified tributyl phosphate at 1270 cm~^ is not a doublet. In all of the tributyl phosphate spectra in this thesis the CH stretch, the CHg stretch shoulder, the CHg bend, the CH3 symmetrical bend, and the P-O-C stretch remain at the same frequencies and exhibit the same relative intensities. There­ fore, they will not be referred to again. The shift of 10 cm~^ indicates bonding of the water to the phosphoryl oxygen. Water saturated tributyl phosphate contains approximately one mole of water per mole of tributyl phosphate. Therefore, the complex TBP'HgO is indicated. Cobb (12) showed that under his particular experimental conditions, addition of water to pure tributyl phosphate resulted in the decrease of the P -—> 0 unbonded group intensity at 1283 cm~^ and the increase of a complex band intensity at 1267 cm~^. At saturation, only the P —> 0 complex band at 1267 cm~^ was present. Table 4 is a summary of data from the spectra of the tributyl phosphate-nitric acid system. The samples were prepared by contacting water equilibrated tributyl phosphate solutions with aqueous solu­ tions of nitric acid. The P —> 0 stretch band shi ft.s 22

Table 4. Spectra of tributyl phosphate, nitric acid system

Figure Solvent Cell HNO^ normality

13 Purified TBP Servofrax 0.52 14 Purified TBP Servofrax I.36 15 Purified TBP Servofrax 2.72 16 Purified TBP Servofrax 4.4 17 Purified TBP Servofrax 5.1

continually to lower frequencies until at 5»1 normal nitric acid in tributyl phosphate it is at 1185 cm"-*-. As the nitric acid concentration increases the following result: 1. The NOg asymmetrical stretch due to nitric acid increases in intensity at 1648 cm-1. 2. The NOg symmetrical stretch at 1310 cm"^ increases in intensity. 3. As the nitric acid normality increased from O.52 normal to 1.36 normal the OH stretch at 3^30 cm~^ due to water in tributyl phosphate decreases and at 2.72 normal it has essentially disappeared. See Figures 13, 14 and 15* 4. At 2.72 normal, nitric acid the OH stretch due to complexed nitric acid appears and increases in intensity at about 2530 cm~^. See Figure 15» For an extensive infrared spectra treatment of the 23 tributyl phosphate-nitric acid system see Kinney (33)* His main conclusions were that: 1. A strong TBP* HNO^ complex forms by hydrogen bonding at the P —> 0 site of the tributyl phosphate. 2. Past a one-to-one nitric acid to tributyl phosphate mole ratio in the organic phase, additional nitric acid is present in the solution through a mechanism of of nitric acid in the strong TBP-HNO^ complex.

Tributyl Phosphate, Uranyl Salt, Nitric Acid System

Table 5 is a summary of data from the spectra of the tributyl phosphate, uranyl nitrate system.

Table 5» Spectra of tributyl phosphate, uranyl nitrate system

Figure Solvent Cell UC^tNCL^ concentration

19 Purified TBP Servofrax 0.13 molar 20 Purified TBP Servofrax 0.44 molar 21 Purified TBP Servofrax 0.91 molar 22 Purified TBP Servofrax 1.0 molar 23 Purified TBP Servofrax Saturated

29 TBP in CC14 NaCl Saturated 24

The spectra were recorded on a Perkin-Elmer Model 21 spectrophotometer as percent transmlttance versus drum rota­ tion. The drum rotation was converted to common frequency- units by using the instrument's conversion curve. The samples were prepared by contacting water equilibrated tributyl phosphate with various concentrations of uranyl nitrate in water and in the last case with excess crystals present in the system. As the uranyl nitrate concentration in tributyl phosphate increases the following result: 1. The P —> 0 complex band at 1180 cm~^ increases in intensity. 2. The uranyl ion band at 930 cnT^ increases in intensity. 3» The NOg asymmetrical stretch band at 1520 cm~^ increases in intensity. 4. The NOg symmetrical stretch band at 1275 cm~^ decreases in intensity resulting in no niticeable change in intensity among the five spectra for the total band at about 1280 cm"-'-. At saturation the band at 1280 cnf^ represents entirely the NOg symmetrical stretch. Figure 29 is a spectrum of saturated uranyl nitrate in tributyl phosphate which was diluted to about 20 volume percent with carbon tetrachloride. The P —> 0 stretch complex band is at 1183 cm~^. The NOg asymmetrical stretch is at 1510 cm~^ and the N0g symmetrical stretch at 1275 cm"^. Because of the greater resolving power of the automatic 25

Perkin-Elraer Model 21 spectrophotometer with sodium chloride cells, more accurate frequency assignments can be made for the various bands than with the servofrax cells. Unless otherwise mentioned all spectra were recorded on an automatic Perkin- Elmer Model 21 spectrophotometer. For saturated uranyl nitrate in tributyl phosphate using servofrax cells and the automatic recorder, the P —> 0

1 stretch complex band is at 1180 cm"" , the N02 asymmetrical stretch at 1510 cm~^, and the N02 symmetrical stretch at 1275 cm"1. Table 6 is a summary of data from the spectra of the tributyl phosphate, uranyl nitrate, nitric acid system.

Table 6. Spectra of tributyl phosphate, uranyl nitrate, nitric acid system

Figure Solvent Cell Initial aqueous solute molarity

18 Purified TBP Servofrax 3-1 hn0-, 2.68 uo2(no3)2 24 Purified TBP Servofrax 3.1 hn0_, 1.34

25 Purified TBP Servofrax 3-1 hn0-, 0. 268 u02(n03)2

26 Purified TBP Servofrax 7.8 hnom, 1.68 uo2(NO3)2

27 Purified TBP Servofrax 4.51 hno3, 1.68 uo2(no3)2

28 Purified TBP Servofrax 1.13 hno3, 1.68 uo2(no3)2 26

The samples were prepared by contacting water equilibrated tributyl phosphate with various concentrations of uranyl nitrate and nitric acid in waterv As the initial uranyl nitrate aqueous concentration decreases and the initial nitric acid aqueous concentration remains constant, the following result: 1. The NOg asymmetrical stretch due to nitric acid at 1635 cm"1 increases as more of the unbonded P —> 0 is available for complexing nitric acid. 2. The NO2 asymmetrical stretch due to uranyl nitrate at 1516 cm"1 decreases. 3. The P —> 0 complex band at about 1180 cm"1 decreases until in Figure 26 it is replaced by a band at 1228 cm"1 due mainly to nitric acid. 4. The NOg symmetrical stretch for uranyl nitrate at about 1275 cm"1 decreases. 5. The uranyl ion band at 930 cm"1 decreases. As the initial nitric acid aqueous concentration decreases and the initial uranyl nitrate aqueous concentration remains constant, the following result: 1. The uranyl ion band at 930 cm~l remains constant in intensity.

-1 2. The N02 symmetrical stretch band at 1275 cm due to uranyl nitrate remains constant in intensity. 3. The NC>2 asymmetrical stretch band at 1516 cm"1 remains 27

constant in intensity. 4. In Figures 27 and 28 a broad band centered at 1192 cm"1 includes both the tributyl phosphate-uranyl nitrate complex band at 1180 cm-1 and a tributyl phosphate-nitric acid complex band in the vicinity of 1208 cm"1. In Figure 29 the P —> 0 complex band is centered at 1185 cm"1 as the nitric acid concentration has decreased even more. 5» The NOg asymmetrical stretch due to nitric acid at 1640 cm-1 decreases. 6. The OH complex stretch at 2530 cm-1 for nitric acid decreases. Table 7 is a summary of data from the spectra of the tributyl phosphate-uranyl chloride system and the tributyl phosphate-uranyl perchlorate system. The aqueous uranyl chloride was prepared by reacting stoichiometrically with . The samples were obtained from water equilibrated tributyl phosphate which was contacted with various concentrations of aqueous uranyl chloride solution. As the uranyl chloride increases in concentration in the tributyl phosphate phase the following result: 1. The P —> 0 complex band increases at 1185 cm"1 and the P —> 0 uncomplexed band disappears at 1275 cm"1. 2. The uranyl ion band increases at 930 cm"1. 3* The OH stretch at 3^30 cm"1 disappears in Figure 32. 28

Table ?• Spectra of tributyl phosphate, uranyl chloride system and tributyl phosphate-uranyl perchlorate

Figure Solvent Cell Solute concentration

30 Purified TBP Servofrax Initial aqueous UOgClg concentration- 1/3 saturated 31 Purified TBP Servofrax Initial aqueous UOgClg coneentrâtion- 1/2 saturated 32 Purified TBP Servofrax Initial aqueous UOgClg concentration- saturated 33 TBP in CCI4 NaCl Initial aqueous UO2CI2 concentration- saturated 34 Purified TBP Servofrax Saturated IK^CClO^Jg

4-. The OH bend at 1620 cm-1 decreases in intensity. The results of the uranyl chloride spectra show that the band appearing at about 1275 cm"1 in the more concentrated uranyl nitrate-tributyl phosphate systems is definitely a band due to the nitrate group. Figure 33 shows the spectra of uranyl chloride in tributyl phosphate which was diluted with carbon tetrachloride to about 20 volume percent. The P —> 0 complex band is at 1167 cm"1 representing a shift of 108 cm"1. As mentioned 29 earlier the frequencies using the sodium chloride cells are considered more accurate due to the better resolution of bands obtained. Figure 34 shows the spectra of saturated uranyl perchlorate in tributyl phosphate. The P —> 0 stretch complex band is at 1183 cm"1.

Tributyl Phosphate, Thorium Nitrate, Nitric Acid System

Table 8 is a summary of data from the spectra of the tributyl phosphate-thorium nitrate system.

Table 8. Spectra of tributyl phosphate, thorium nitrate system

Figure Solvent Cell Th(N03)4 concentration

36 Purified TBP Servofrax 0.12 molar 37 Purified TBP Servofrax 0.44 molar 38 Purified TBP Servofrax 0.82 molar 39 Purified TBP Servofrax 1.01 molar 40 Purified TBP Servofrax Saturated

35 TBP in CC14 NaCl Saturated

The spectra were recorded on a Perkin-Elmer Model 21 spectrophotometer as percent transmittance versus drum rota­ 30 tion. The drum rotation was converted to common frequency- units by using the instrument's conversion curve. The samples were prepared by contacting water equilibrated tributyl phosphate with various concentrations of thorium nitrate in water. The spectrum shown in Figure 40 was obtained from the tributyl phosphate thorium nitrate-water system con­ taining excess crystals of thorium nitrate. As the thorium nitrate concentration in the tributyl phosphate is increased, the following result: 1. The P —> 0 complex band at about 1180 cm"1 increases in intensity. 2. The unbonded P —> 0 band at 1280 cm"1 decreases and the NOg symmetrical stretch at about the same frequency increases resulting in the relative intensity of the overall band remaining the same. 3. The NOg asymmetrical stretch band at about 1520 cm-1 increases. At saturation the band at 1300 cm"1 is probably represented partially by the N02 symmetrical stretch and partially by the unbonded P —> 0 stretch. The determination of whether or not the latter is partially responsible for the band depends upon what is taking place at saturation of thorium nitrate in tributyl phosphate. The solubility of thorium nitrate in tributyl phosphate at room temperature is

!*•'?_ n-viomc owtnrrlwnHp o o 1 +• /l flH rrmam c? cnl lif.l nM ( wV) i P.VL 7 R 31 almost exactly halfway between the values which are calculated from Th(N03)4'3TBP and ThfNO^^TBP. He sford £fc al. (24) state that only the Th(NCy)^'2TBP complex is present which means that unbonded P —> 0 molecules will be present. They say that the composition of a saturated solution approaches

Th(N03)4*2TBP at 100 °C. Katzin ai.. (32) state and give evidence that there is present a mixture of two species, equally abundant, one of which contains two molecules of tributyl phosphate per thorium atom, and one which contains three molecules of tributyl phosphate per thorium atom. The infrared spectra obtained by the author indicate that only one complex is present. Figure 35 shows a spectrum of saturated thorium nitrate in tributyl phosphate which was diluted with carbon tetrachloride to about 20 volume percent. The P —> 0 complex

l 1 band is at 1174 cm~ , the N02 symmetrical stretch at 1275 cm" ,

1 and the N02 asymmetrical stretch at 1503 cm" . For thorium nitrate in tributyl phosphate using servofrax cells and the automatic recorder, the P —> 0

1 complex band is at 1182 cm" , the N02 symmetrical stretch

1 1 at 1290 cm" , and the N02 asymmetrical stretch at 1515 cm" . Table 9 is a summary of data from the spectrum of the tributyl phosphate-nitric acid-thorium nitrate system. Water equilibrated tributyl phosphate was contacted with concentrated nitric acid and then saturated with thorium 32

Table 9» Spectrum of tributyl phosphate, thorium nitrate, nitric acid, servofrax cell, Figure 41

Band Wave number (cm-1)

P —> 0 stretch complex 1170 NC>2 symmetrical stretch for ThtNO^)^ 1280

NC>2 asymmetrical stretch for Th(N0^)4 1522 N02 symmetrical stretch for HNO^ 1310 NOg asymmetrical stretch for HNO^ 1664

nitrate. The P —> 0 stretch complex band is at 1170 cm"1 which is in about the same position as that of tributyl phosphate-thorium nitrate without nitric acid (1182 cnr1). There is no evidence of more than one complex as has been suggested by Peppard al. (45). The N02 symmetrical stretch due to nitric acid, which is at about 1310 cm"1, is included in the NOg symmetrical stretch band of thorium nitrate.

Tributyl Phosphate, Bare Earth Nitrate, Nitric Acid Systems

Table 10 is a summary of data from the spectra of the tributyl phosphate-samarium nitrate system. The solutions were obtained by contacting water equilibrated tributyl phosphate with various concentrations of samarium nitrate in water. A Perkin-Elmer Model 21 spectro- 33

Table 10. Spectra of tributyl phosphate, samarium nitrate system

Figure Solvent Cell SmfNO^)^ molarity

44 Purified TBP Servofrax 0.13 45 Purified TBP Servofrax 0.5 46 Purified TBP Servofrax 0.9

photometer was used and the data were replotted as described previously. Since a calcium fluoride prism was used, instead of the usual sodium chloride prism, only wave numbers down to 1164 cm""1 could be obtained. As the samarium nitrate concen­ tration increases, the following result: 1. The OH stretch band at 3500 cm"1 disappears completely in Figure 45. 2. The OH bend at 1620 cm-1 decreases and then disappears in Figure 46. Both of these results (1 and 2) are due to the water, which is present initially in a one-to-one mole ratio with tributyl phosphate, being forced out of the organic phase. 3. The NOg asymmetrical stretch increases in intensity at about 1490 cm-"'". 4. The NOg symmetrical stretch increases in intensity at about 1280 cm"1 and the P —> 0 unbonded band at about the same f renuenny ri a r.re «ses in intenni-hv resulting in 34

the relative intensity of the overall band remaining the same. 5. The P —> 0 stretch complex band increases in intensity at about 1208 cm"1. Table 11 is a summary of data from the tributyl phosphate- nitrate-nitric acid system.

Table 11. Spectra of tributyl phosphate, praseodymium nitrate, nitric acid system

Figure Solvent Cell Initial aqueous solute concentration

42 Purified TBP Servofrax Saturated Pr(NO^)^ 43 Purified TBP Servofrax 3.84 molal Pr(NO^)^ 6.3 molar HNO^ 47 Purified TBP Servofrax 3.2 molal PrtNO^)^ 3.1 molar HNO^ 48 Purified TBP Servofrax 2.68 molal Pr(NO^)3 5.2 molar HNO^

The samples were prepared by contacting water equilibrated tributyl phosphate with various concentrations of praseodymium nitrate and nitric acid in water. When praseodymium nitrate alone is present in tributyl phosphate, the P —> 0 stretch complex band is at 120j? cm-1, the NOg symmetrical stretch at 1289 cm"1, and the NOg asym- 35 metrical stretch at 1492 cm*"1. As the initial aqueous concentration of nitric acid increases in proportion to the initial aqueous praseodymium nitrate concentration, the following result: 1. The NOg asymmetrical stretch due to nitric acid increases in intensity at 1640 cm"1. 2. The NOg symmetrical stretch due to nitric acid increases

1 in intensity at 1310 cm" but is included in the N02 symmetrical stretch band for praseodymium nitrate. The NOg symmetrical stretch band for praseodymium nitrate decreases in intensity at 1289 cm"1. The overall band remains roughly the same until in Figure 48 where the resulting band at 1301 cm"1 represents mostly the NOg symmetrical stretch due to nitric acid. 3« The P —> 0 stretch complex band for praseodymium nitrate appears the same as for praseodymium nitrate without any nitric acid. However, the nitric acid complex band is included in the overall band. 4. The OH stretch complex band due to nitric acid increases in intensity at 2530 cm"1. 5. The NOg asymmetrical stretch band for praseodymium nitrate at 1492 cm"1 decreases in intensity. Table 12 is a summary of data from the spectra of the tributyl phosphate-rare earth nitrate system. The table shows the complete rare earth nitrate series in tributyl phosphate. 36

Table 12, Spectra of tributyl phosphate, rare earth nitrate system

Figure, rare P —> 0 P —> 0 N02 sym­ N02 asym­ V4-V1 earth nitrate stretch shift metrical metrical (cm-l) (cm-1) (cm'1) stretch, stretch, (cm"1) (cm"1)

49 - La(N03)3 1200 75 1280 1488 208

50 - Ce(N03)3 1201 74 1280 1488 208

51 - Pr(N03)3 1202 73 1281 1488 207

52 - Nd(N03)3 1203 72 1283 1488 205

53 - Sm(N03)3 1206 69 1284 1488 204

54 - EU(NO3)3 1208 67 1285 1488 203

55 - Gd(N03)3 1209 66 1291 1490 189

56 - Tb(N03)3 1209 66 1292 1492 200

57 - Dy(N03)3 1210 65 1300 1500 200

58 - Ho(N03)3 1213 62 1300 1492 192

59 - Er(N03)3 1211 64 1304 1490 186

60 - Tm(N03)3 1213 62 1306 1496 190

61 - Yb(N03)3 1216 59 1305 1494 189

62 - LU(N03)3 1217 58 1306 1495 189

The samples were prepared by contacting purified tributyl phosphate solutions with nearly saturated aqueous solutions of the rare earth nitrates and diluting the resulting organic phase to 15 - 20 volume percent with carbon tetra- 37 chloride. Sodium chloride cells were used. The aqueous rare earth nitrate solutions were prepared by adding nitric acid to the rare earth oxide and boiling off the excess nitric acid. In the case of v^, the listed frequency represents an approximation due to the overlapping of this band with the CHg bend at 1468 cm"1. The P —> 0 stretch band for tributyl phosphate is located at the frequency 1275 cm"*1. On complex formation, the P —> 0 stretch band is shifted to a lower frequency and the amount of the shift [1275 - P —> 0 complex frequency] is indicative of the strength of the complex formed. From Table 12 the strength of the tributyl phosphate-rare earth nitrate complex apparently increases from lutetium to lanthanum, with the exception of erbium, but this is contrary to extraction data for the tributyl phosphate-rare earth nitrate system with no nitric acid present. The distribution coefficients of the rare earth nitrates increase from lanthanum to gadolinium and then decrease when no nitric acid is present (41). The infrared spectra of the rare earth nitrates in tributyl phosphate indicate that the tributyl phosphate might prefer the lighter rare earth nitrates in comparison to the heavier rare earth nitrates. To test whether the tributyl phosphate prefers praseodymium nitrate over neodymium nitrate or vice versa, the following experiment was devised. A tributyl phosphate-water-neodymium nitrate-praseodymium nitrate 38 system was equilibrated with excess crystals of both nitrates present. This enabled both the organic and aqueous phases to pick up all of each nitrate that they could. The results of the experiment are given in Table 13. The differential spectrophotometry determination was used (3,4).

Table 13* Tributyl phosphate-water-neodymium nitrate- praseodymium nitrate system with excess of both solid nitrates present

Sample Nd(NO^)^ per Pr(NO^)^ per gram solution gram solution

TBP 0.1414 O.I38O Duplicate TBP 0.1416 0.1385 Aqueous 0.2377 0.3781 Duplicate aqueous O.2386 0.3775

These results show that the separation of praseo­ dymium nitrate and neodymium nitrate is principally due to the preference of the aqueous phase for praseodymium rather than a strong preference of the tributyl phosphate for neodymium. Additional work needs to be done to see if this observation holds throughout the rare earth series. The work would consist of using other rare earth nitrate systems in tributyl phosphate, such as samarium-praseodymium, samarium- 39 neodymium, and neodymium-erbium. Other solutes such as uranyl nitrate and thorium nitrate could be used in similar studies. Various solvents such as phosphates, phosphine oxides, ketones, amines, ethers, alcohols, acetates, and others could be used to see if this observation applies to other solute-solvent systems. Table 14 shows data from the spectrum of yttrium nitrate in 20 volume percent tributyl phosphate in carbon tetrachloride plus the results of lanthanum nitrate, cerium nitrate, and samarium nitrate in tributyl phosphate using servofrax cells.

Table 14. Spectrum of tributyl phosphate-yttrium nitrate plus the results of La(N03)3, Ce(N03)3, and Sm(N03)3 in tributyl phosphate

Figure Cell Concen­ P —> 0 N02 sym­ NO2 asym­ tration, stretch metrical metrical salt (cm-1) stretch stretch (cm-1), (cm-1), V4

63 NaCl Nearly 1211 1303 1492 saturated Y(N03)3 Not Servofrax Nearly 1212 1287 1480 shown saturated La(N03)3 Not Servofrax Nearly 1208 1287 1480 shown saturated Ce(N03)3 Not Servofrax Nearly 1210 1290 1492 shown Sm(N03)3 40

Tributyl Phosphate, Ferrie Sait Systems

Table 15 is a summary of data from the spectra of the tributyl phosphate-ferric nitrate and tributyl phosphate- ferric chloride systems. In the case of ferric chloride (Figure 65) the unbonded P —> 0 stretch band has practically disappeared showing that all the P —> 0 molecules are bonded. The solubility of ferric chloride in tributyl phosphate was close to that calculated by FeCl^e3TBP so that this complex apparently was formed.

Table 15* Spectra of 20 percent tributyl phosphate in carbon tetrachloride, ferric salt systems

Figure Cell Concen­ P —> 0 NO2 sym­ NO2 asym­ tration, stretch metrical metrical salt (cm"1) stretch stretch (cm"1), (cm"1), V1 v4

64 N&Cl Saturated 1180 1270 1520 Fe(N03)3 65 NaCl Saturated 1195 FeCl3

Tributyl Phosphate, Divalent Salt Systems

Table 16 is a summary of data from the spectra of tributyl phosphate-divalent salt systems. Due to the water 41

Table 16. Spectra of tributyl phosphate, divalent salt systems

Figure Concen­ Cell P —> 0 NO2 sym­ NO2 asym­ tration, stretch metrical metrical salt (cm""1) stretch stretch (cm-1), (cm-1), V1 v4

66 Saturated NaCl 1208 1280 1511 CU(N0^)2 67 Saturated NaCl 1221 1275 1468 Cd(N03)2 Not Cd(NO^)2 Servo­ 1235 1290 1470 shown frax 68 Saturated NaCl 1240 1307 1450 Ca(NO^)2

Not Ca(N03)2 Servo­ 1255 1313 1468 shown frax 69 Saturated Servo­ 1235 1290 1500 Zn(NO )g frax 70 Nearly Servo­ 1250 saturated frax Ba(SCN)2 71 Nearly Servo- 1242 saturated Sr(SCN)2

in hydrated cadmium nitrate [CdfNO^Jg^HgO], the OH stretch band was at about 3^-50 cm"1 and the OH bend at 1635 cm-1. When sodium chloride cells were used, a solid form would occasionally stick to the cells. Figure 72 shows ferri r. 42 nitrate in the solid form. The band at about 1352 cm-1 is

that of the ionic nitrate i.e. the N02 asymmetrical stretch. It is not known whether a slight amount of nitrate is in the ionic form in the organic phase or whether there is a reaction of the nitrato group with the sodium chloride windows to form the ionic nitrate. However, solid sodium chloride was added to all tributyl phosphate samples in an attempt to eliminate this problem. This was also done for all the remaining solvents.

Tri-n-octyl Phosphine Oxide, Uranyl Salt Systems

Table 1? is a summary of the data from the spectrum of tri-n-octyl phosphine oxide. All the CH, CH2, and CH^ bands remain at constant intensity on the addition of solutes and therefore will not be mentioned again.

Table !?• Spectrum of 0.1 molar tri-n-octyl phosphine oxide in carbon tetrachloride, NaCl cells, Figure 73

Band Frequency (cm""1)

CH stretch 2920

CH2 stretch shoulder 28 jO

CH2 bend 1466 CH^ symmetrical bend 1378 P —> 0 stretch 1164 43

Table 18 is a summary of data from the spectra of the tri-n-octyl phosphine oxide-uranyl nitrate system.

Table 18. Spectra of tri-n-octyl phosphine oxide, uranyl nitrate system

Figure Solvent Cell Initial UOgCNO^g aqueous concentration

74 0.1 molar TOPO in CCl^ NaCl 0.00735 molar 75 0.1 molar TOPO in CCI4 NaCl 0.0296 molar 76 0.1 molar TOPO in CCl^ NaCl Saturated

The samples were prepared by contacting 0.1 molar tri-n-octyl phosphine oxide in carbon tetrachloride with different aqueous concentrations of uranyl nitrate. As the uranyl nitrate concentration increases in the organic phase, the following results are noted: 1. The P —> 0 stretch complex band at 1105 cm"1 increases in intensity. 2. The P —> 0 stretch unbonded band decreases in intensity until at saturation (where UOgtNO^^* 2T0P0 is composition of organic phase) it has disappeared.

1 3. The N02 asymmetrical stretch at 1510 cm" increases in intensity. 4. The NOg symmetrical stretch band at 1280 cm"1 increases ii4

in intensity. 5. The uranyl ion band at 930 cm-1 increases in intensity. Table 19 is a summary of data from the spectra of the tri-n-octyl phosphine oxide-uranyl chloride and tri-n-octyl phosphine oxide-uranyl perchlorate systems.

Table 19. Spectra of tri-n-octyl phosphine oxide, uranyl chloride and tri-n-octyl phosphine oxide, uranyl perchlorate

Figure Salt Solvent Cell P —> 0 stretch (cm"1)

77 U02C12 0.1 molar TOPO NaCl 1098 in CC14 78 UCMCIOk)? 0.1 molar TOPO NaCl 1090 in CC14

0.1 molar tri-n-octyl phosphine oxide in carbon tetrachloride was contacted respectively with aqueous solu­ tions of uranyl chloride and uranyl perchlorate. The uranyl chloride was prepared by reacting uranium trioxide (UO^) stoichiometrically with hydrochloric acid. The uranyl perchlorate was prepared by reacting uranium trioxide stoichiometrically with perchloric acid. 45

Tri-n-octyl Phosphine Oxide, Various Salt Systems

Table 20 is a summary of data from the spectra of the tri-n-octyl phosphine oxide-various salt systems.

Table 20. Spectra of 0.1 molar tri-n-octyl phosphine oxide in carbon tetrachloride, various salt systems, sodium chloride cells

Figure Salt p —> 0 N02 sym­ N02 asym­ stretch metrical metrical (cm-1) stretch stretch (cm-1), (cm"1), V/

79 Th(1103)4 1103 1300 1492

80 Ce(NO^)3 1123 1287 1465

81 Pr(N03)3 " 1124' 1290 1465

82 Nd(N03)3 1124 1290 1465

83 Sm(N03)3 1124 1290 1465

84 Fe(N03)3 1092 1272 1505

85 FeCl3 1079

86 Zr(N03)4 1090 1280 1520

87 Hf(N03)4 1105 1280 -

88 H2Ce(N03)6 1058 1262 1510

89 Zn(N03)2 1120 1289 1492

90 Cd(N03)2 1130 1290 1460 91 SnCl^ 1093

92 Co(N03 )2 1120 1278 1492

93 CoCl2 1111 46

0.1 molar tri-n-octyl phosphine oxide in carbon tetrachloride was contacted with various saturated aqueous solute solutions to give the data in the table. In Figures 86, 8?, and 88 the particular salts shown in the organic phase result from zirconyl nitrate, hafnyl nitrate, and ammonium eerie nitrate [(NH^^CetNO^)^] in the aqueous phase respectively. In the case of hafnium nitrate the N02 asym­ metrical stretch is masked for reasons unknown. It should appear in the vicinity of 1500 cm"1.

Methyl Isoamyl Ketone, Salt Systems

Table 21 shows the spectrum of methyl isoamyl ketone

[ch3cch2ch2ch(ch3)2].

Table 21. Spectrum of methyl isoamyl ketone, servofrax cell, Figure 94

Band Frequency (cm-1)

CH stretch 2930 C=0 stretch 1715

CH2 bend 1472 CH^ symmetrical bend 1365 Unknown 1169 47

Table 22 is a summary of data from the spectra of the methyl isoamyl ketone, saturated salt systems.

Table 22. Spectra of methyl isoamyl ketone, saturated salt salt systems, servofrax cells

Figure Salt 0=0 N02 sym­ N02 asym­ N-0 stretch metrical metrical stretch (cm-1) stretch stretch (cm"1) (cm-1), (cm™1), V1 v4

95 UO2(NO3)2 1700 1272 1530 1027 96 UOgClg 1700

97 Th(N03)4 1700 1292 1532 1028

For each solute, the 0=0 stretch band has shifted to 1700 cm-1 from 1715 cm-1 indicating that the carbony1 oxygen is the point of attachment of the solute. The CH stretch,

the CH2 bend, and the CH^ symmetrical bend bands remain unchanged in frequency. For Figure 93» the OH stretch at about 3300 cm-1 results from the water in the hydrated solid [IK^NO^^'ô^O]. The uranyl ion band is at 946 cm-1. For Figure 94, the uranyl ion band is at 920 cm-1. Similar results were obtained using hexone 0 [CH^CCHgCHfCH^jg] as a solvent. In that case the shift of

n~n *• +- — ~i4-" 1- 7"-" —; innn 1 x. „ i iOt 1 -P~— 48 uranyl nitrate and thorium nitrate. For carbonyl compounds the shift of the C=0 stretch was not great enough to correlate it with any properties of the solute.

HDPM, Uranyl Nitrate System

Table 23 is a summary of data from the spectra of the HDPM and HDPM-uranyl nitrate systems.

Table 23. Spectra of HDPM, uranyl nitrate system, sodium chloride cells

Band Figure 98 Figure 99 0.1 molar HDPM Nearly saturated in CCl4(cm-l) uogfno-^g in 0.1 molar HDPM- CCljij,(cm-l)

CH stretch 2930 2930 CHg stretch shoulder 2850 2850 CHg bend 1461 1461 CH3 symmetrical bend 1372 1372 P —> 0 stretch 1170 1130 Uranyl ion 930 NO2 symmetrical stretch 1275 NC>2 asymmetrical stretch 1495 N-0 stretch 1030 49

A solid at room temperature HDPM (bis [di-n- hexylphosphinyl] methane) has the formula

0 0 f t ^•3c6- f~ chs~ c6%3 c6h13 =6^3

The P —> 0 stretch complex band appears at 1130 cm which indicates attachment of the solute to the phosphoryl oxygen.

Tri-n-octyl Amine, Uranyl Nitrate System

Table 24 is a summary of data from the spectra of the tri-n-octyl amine and tri-n-octyl amine-uranyl nitrate systems. The C-N stretch complex band is at 1015 cm"1. The shift to a lower frequency indicates attachment of the solute to the nitrogen atom. 50

Table 24. Spectra of tri-n-octyl amine, uranyl nitrate system, sodium chloride cells

Band Figure 100 Figure 101 15 percent Nearly saturated TOA in CC14 U02(NC>3)2 in 15 percent TOA- CCI4

CH stretch 2930 2930

CH2 stretch shoulder 2850 2850

CH2 bend 1468 1468 CH^ symmetrical bend 1372 1372 C-N stretch 1090 1015 Uranyl ion 942

N02 symmetrical stretch 1260

N02 asymmetrical stretch 1510 51

DISCUSSION OF RESULTS

General Comments

In all of the solutes examined in phosphoryl solvents only one P —> 0 stretch complex band was formed. This indicated the presence of one particular complex. The lowering of the frequency of the P —> 0 stretch band in phosphoryl solvents upon the addition of a solute to the organic phase indicated that the solute was attached to the phosphoryl oxygen of the solvent. No noticeable change was evident in the frequency of the P-O-C stretch band of tributyl phosphate. This indicated that the oxygen of the butyl group was not involved in the complexing of the solute. The P —> 0 stretch complex band, due to the addition of the solute to tributyl phosphate, remained at the same frequency regardless of the amount of nitric acid present. This was true for the systems uranyl nitrate-nitric acid- tributyl phosphate, thorium nitrate-nitric acid-tributyl phosphate, and praseodymium nitrate-nitric acid-tributyl phosphate. In some cases a broad band was formed, including both the P —> 0 stretch complex band for the solute and the P —> 0 stretch complex band for nitric acid. Under the particular set of experimental conditions used in this work, the spectra frequencies were reproducible 52 within + 2 cm-1. However, using different diluents, different cells, and different instruments, a much different value for some of the frequencies would be obtained. The diluent and type of cell used are critical in this respect. Also, a difference in the type or extent of hydration of the solute probably alters some of the frequencies.

Spatial Configuration

Empirical studies by Gatehouse si &1. (17) and others (15,16,53) indicated that most nitrates are of the Cgy sym­ metry type with the nitrato group covalently bound through one oxygen atom to the metal atom. The presence of V4 in the region 1481 - 1531 cm-1 and Vj in the region 1290 - 1253 cm"1 indicated the following structure for nitrate solutes (17):

0 m-o—n 0

Spectra of all nitrates in the organic phase run by the author showed V4 and bands. Ionic nitrates of type symmetry, such as sodium nitrate, are only slightly soluble in phos­ phoryl solvents. A typical structure, say for thorium nitrate in tributyl phosphate, would be as follows: 53

o o M 1/ N N v y0

(C4H90)3P —> 0 Th 0 <— P(C4H90)3

/° °\ N N

i\ /i0 0

P —> 0 Shift

A plot was made of ionic potential (charge/ionic radius) of the solute versus P —> 0 stretch frequency for both tributyl phosphate and tri-n-octyl phosphine oxide. The results are shown in Figures 1 and 2. For each solvent, an essentially linear relation was obtained. This represents the best correlation found of P —> 0 stretch frequency shift with a specific property of the solute. In the case of uranyl nitrate, the charge on the cation was taken as +4 in accordance with the work of Connick and Hugus (13) who determined the charge on the uranium as approximately +4 with each oxygen of the uranyl ion having a charge of approximately -1. By assuming this charge distribu­ tion, they showed that the entropy of uranyl ion could be accounted for, in the case of ammonium eerie nitrate lco(noy2 2.cd(n0^2 2ly(n0^3

4Cu(N0^2

en 5Ui(N0j3 rj 6Yb(N03)3 7tm(n03)3 cc aho(nc>3)3

0 9Er(N03)3 1 10.dy(n03)3 x 11.Tb(N03)3 LU 0 12.Gd(N03)3 Vn 13.EU(N02)3 -fr 1o 14. Sm (N03)3 15.Nd (N03)3 l&Pr (NO3)3 17.Ce (NO3)3

LU 18.L0 (N03)3

<5 19.F

21 .Fe(N03)3

22.Th(N03)4 23.U0oClo

P—0 SHIFT (CM1) Figure 1 Plot of ionic potential versus P —> 0 shift for the tributyl phosphate-solute system 3to £ tr I.Cd (M03 )2 o 2.Sm (NÛ3>3 zo 3.Nd (N03)3 4Pr (NO3)3 LU !>.Ce (NO 3)3 6co(n0 3) 1 2 X 7zn(n0 3)2 o vi acoci2 vjl

ant (NO3)4 " < iauo^no3)2 i— II. Th (NO 3)4 I 12.U02CI2 CL 13. Sn CI4 y 14. Fa (NO 3)3 15.Zr(N03)4 § l&u02(ci04)2 17 Fa CI3

l&H^Ce(N03)6

0 10 20 30 40 50 60 70 80 90 100 P—-0 SHIFT (CM™1) Figure 2. Plot of ionic potential versus P —> 0 shift for the tri-n-octyl phosphine oxide-solute system 56

[(NH4)2Ce(N03)^] in tri-n-octyl phosphine oxide it was assumed that the complex I^CetNO^)^* 2T0P0 was formed. This assumption was made by White and Boss (56)» The charge used in the ionic potential correlation was +6, that is, the total positive charge. The ionic radii were taken from Molecular Science and Engineering (52). The empirical values were used, when avail­ able, rather than the calculated values. It would be expected that the higher the ionic potential of the solute the stronger the bond formed between it and the solvent. From theoretical considerations the P —> 0 stretch frequency shift is interpreted as indicative of the strength of the complex formed, possibly quantita­ tively. Thus, the correlation of P —> 0 stretch frequency shift and ionic potential is consistent with these viewpoints. The greater shift of the P —> 0 stretch frequency in both tributyl phosphate and tri-n-octyl phosphine oxide due to uranyl chloride compared to uranyl nitrate, using sodium chloride cells, may be due to a stronger bond. Sato (46) reports that the decreased back extraction of uranyl nitrate by chlorides must be the result of the stronger complexing of uranyl chloride by tributyl phosphate opposing the back extraction of uranyl ion as nitrate. For tributyl phosphate an essentially linear relation exists between P —> 0 stretch frequency shift and grams of 57 extractable species per 100 grams of complex with two exceptions, ferric chloride and ferric nitrate. Grams of extractable species per 100 grams of complex can be repre­ sented as 100 / m^ + where m^ = the molecular weight of the solute and mg = the number of tributyl phosphate molecules attached to the metal multiplied by the molecular weight of tributyl phosphate. This relationship apparently represents a reasonably reliable means of estimating the number of tributyl phosphate molecules in the complex. In Figure 3 is plotted grams of extractable species per 100 grams of complex versus P —> 0 stretch frequency shift for tributyl phosphate using sodium chloride cells. Figure 4 shows the same plot using servofrax cells. Better resolution of bands, and hence more accurate frequency readings, can be obtained with the sodium chloride cells. However, infrared spectra of more compounds can be obtained with servofrax cells. The point for water on the sodium chloride diagram was taken from the servofrax diagram since spectra of water in tributyl phosphate cannot be obtained with sodium chloride cells. For tributyl phosphate the following complexes were

T assumed to exist in making the plot: Ca(N03)2*3 BP,

Cd(N03)2«3TBP, TBP-HgO, CufNOjg'ZTBP, Y(NO^)^•3TBP, (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu)

(NO.,),,, UOp(NO,,)p*2TBP, Th(NOq)k*2TBP, U0?C1?.2TBP, LH2O 15. Pr (N03)3

2.CO(N03)2 l& Ce (N03)3 X tu acd (NO3)2 _i 17 La (NO^s CL 4Lu (N0 ) 25 3 3 18. Y (N03)3 5.Yb (NO 3)3 8 50 I9CU(N03)2 6-Tm(N03)3 20. FeCI 3

7. Ho(N03)3 2I.U0j

s

s o I i 40 50 60 70 80 90 100

•0 SHIFT (CM-1 ) Figure 3* Plot of grams of extractable species/100 grams of complex versus P —> 0 shift for the tributyl phosphate-solute system using sodium chloride cells 1 1 1 1 1 1 1 1 1 1

IHgO 13 Th (N03)4

X 2.CO(N03)2 LU I4.U02(N03)2 3.BO(SCN)2

4.Sr(SCN)2

5.Cd(N03)2 50 6.Zn(N0 3)2 13 > tn i 7. La (N03>3 g 8. Sm (NO 3)3 //I4•

o 40 — 9 Ce(N03)3 — o ^il. Vx 10. Pr (NO3)3 md ll.UOgCI 2 30 8 l2.U02(CI

1 1 1 1 1 1 1 1 1 1 10 20 30 40 50 60 70 80 90 100 P-»0 SHIFT (CM"4) Figure 4. Plot of grams of extractable species/100 grams of complex versus P —> 0 shift for the tributyl phosphate-solute system using servofrax cells 6o

FeCly 3TBP, and FefNCyj^'^TBP. Solubility experiments performed on ferric nitrate and ferric chloride in purified tributyl phosphate gave values corresponding almost exactly to the complexes

Fe(N03)y 3TBP and FeCly3TBP. Also, Majumdar and De (35) report the complex FeCl^^TBP at 2 molar hydrochloric acid. Specker and Cremer (50) report the same complex at 4 molar hydrochloric acid. Both used the method of plotting the log of the distribution coefficients against the log of the tributyl phosphate concentration in a diluent and recording the slope of the straight line formed. The other complexes listed above are generally considered to exist (23,37), except for possibly the copper nitrate complex. Here, the Cu(N03)2»2TBP complex was assumed because the solubility of copper nitrate in tributyl phosphate was greater than that calculated from Cu(N03)2*3TBP. Figure 5 shows the plot of grams of extractable species per 100 grams of complex versus P —> 0 stretch frequency shift for tri-n-octyl phosphine oxide. The correla­ tion in this case was apparently not as good as for tributyl phosphate. The following complexes were assumed to exist in making the plot: U02(NO^)2* 2T0P0, U02C12*2T0P0, U02(C10^)2*

2T0P0, Th(N03 V2T0P0, Ce(N03)y 3T0P0, PrU'JO^y 3TOPO,

Nd(NCy)_'3T0P0, Sm(NG3)3*3TOPO, FetNO^y 2T0P0, FeClyTOPO,

Zr(N0^)^* 2T0P0, Hf(N0q)^*2T0P0, H2Ce(N03)6'2T0P0, Zn(NCy)2' 1 1 1 1 1 1 1 1 1 1

L Cd (N03)2

2. Sm(N03)3 X 3.Nd(N03)3

s 4 Pr (NO 3) 3 8 5.Ce(N03)3 Lb. o 6-Zn(N03)2 en 7. Co (NO 3)2 g 8.Cod 2 _ 9Hf (N03)4 o 40 o IO.UO2(NO3)2 18* 13- Os II. Th (NO 3)4 9. y 10. 30 _ LAUC^CI 2 y I2>^^ 14 « » 17* — I3.U0^CI04)2

UJ l4.7r(N0^4 2* 16® _ 15-SnCI 4 4^// 1 20 l6.Fe(N03)3 s 6» 0 h 17 FeCl 3 8 X 7» UJ IAH^e(N0 ) (z) 10 3 6 ig

1 1 1 1 1 1 1 1 1 10 20 30 40 50 60 70 80 90 100 P—O SHIFT (CMJ) Figure 5* Plot of grams of extractable species/100 grams of complex versus P —> 0 shift for the tri-n-octyl phosphine oxide-solute system 62

3T0P0, Cd(N03)2«3T0P0, SnCl4'2T0P0, Co(NC>3)2*3TOPO, and

CoCl2*2T0P0. The ferric nitrate and ferric chloride complexes were assumed from solubility data run by the author. The other complexes were analogous to those with tributyl phosphate and were consistent with reported results (56).

Covalency of the Solute

Nitrates such as sodium nitrate, potassium nitrate and other ionic nitrates have symmetry. However, most of the heavier nitrates have C2v symmetry. According to the interpretation of Perraro (15), the frequency difference ~ V1 ^presents the degree of covalence of a nitrate compound. In methyl nitrate in which the bonding to the oxygen must be predominately covalent, the maximum splitting occurs (10). Ferraro (15) thus assumed a linear relation between the frequency difference and the amount of covalence of a nitrate compound. However, probably represents only a rough approximation of the covalence of a nitrate compound. In Figure 6, the frequency difference - v^, as obtained from these spectra, is plotted against the correspond­ ing P —> 0 stretch frequency shift for tributyl phosphate. Figure ? represents the plot of against P —> 0 stretch frequency shift for tri-n-octyl phosphine oxide. It 300

2 o 19' • 21 17 18 tr 1214 15 16 a 200

% ri3 1.CO(N03)2 12.Eu(N03)3 •10 y 2.cd(n03)2 13.Gd(N0&

5 3.Cu (N03)2 14. Sm(N03)3 CE 4lu(n03)3 15.Nd (N03)3

5.Yb(N03)3 l&Pr (N03)3

6.Ho (NO^g l7.Ce(N03)3 d 100 m 7Tm(N03)3 IB.Lo (N03>3 BDy (NOsls § I9.UC^(N03)2 tr aY(N0;j)3 2QFe(N03)3 10.Er(N0j3 2LTh (N03)4

11.Tb(N03)3

JL i 10 20 30 40 50 60 70 80 90 100 P—0 SHIFT (CM"')-i Figure 6« Plot of the frequency difference versus P —> 0 shift for the tributyl phosphate-metal nitrate system I.Cd(N03)2

i 2.Sm(N03)3 200 st 3.Nd(N03)3

4.Pr(N03)3 ON 5.ce(n03)3 •Çr ecofnojjj, 7 ZntNO^g 8.u02(n03)2 Iq aTh (NO 3)4 100 10.Zr (N03)4

o II. Fe(N03)3 I iz.hgcetnojjg

10 20 30 40 50 60 70 80 90 100

P—O SHIFT (CM"') Figure 7• Plot of the frequency difference - v-^ versus P —> 0 shift for the tri-n-octyl phosphine oxide-metal nitrate system 65 is apparent that there is a rough linear correlation between the P —> 0 stretch frequency shift and the amount of covalence of a nitrate when in a particular solvent. These correlations are consistent with the fact that the ionic potential, which correlates with P —> 0 shift, is directly related to the amount of covalence in a compound. If covalence is defined as the resistance to ionization or the sharing of electrons, one would expect that a high charge on the cation of a solute and a small radius would bring it closer to the anion and thus form a stronger and more covalent bond due to the overlapping of orbitals (38, pp. 208-211). The values for the frequency difference will vary somewhat depending upon what experimental conditions the nitrate compound is under. Ferraro (16) has values for some nitrates in tributyl phosphate and as solid nitrate hydrates. The values of - V]_ used here were taken directly from the spectra of the various nitrate solutes in the solvents. The separation of and is related to the ionic potential of the nitrate. The smaller the size and/or the greater the charge of a cation, the greater the induced distortion or polarization of the anion. When ions approach each other closely, the attraction of the cation for the electron atmosphere of the anion and the simultaneous repul- 66 s ion of the nucleus of the anion result in deformation, distortion, or polarization of the anion. The net effect of ion polarization is an increase in the degree to which electrons are shared or an increase in covalent character (38, pp. 208-211). Although the assignment cf an amount of "covalence" to a nitrate based on the frequency difference may be questionable, the correlation of P —> 0 stretch frequency shift with - Vj is consistent with the fact that covalent solutes are extracted better than ionic solutes.

General Extraction Theory

Within a particular class of solvents, such as those containing the phosphoryl group, one can make some reasonable predictions as to how efficient (in terms of the distribution coefficient) a particular solvent will be in extracting a metallic salt. Burger (11) has correlated the frequency of the P —> 0 stretch band in various phosphoryl solvents with the distribution coefficient of 0.2 molar uranyl nitrate between the solvent and water€ He grouped the solvents into four groups for the correlation: phosphine oxides, phos- phinates, phosphonates, and phosphates. Bell âi.. (6) has correlated the frequency of the P —> 0 stretch with the sum of the Pauling electronegativities of the groups X, Y, Z in the molecule (XYZ)P —> 0. When X, Y, or Z is a molecule 67 containing several atoms, the electronegativity is obtained by a value which fits the correlation in a large number of compounds and is called a phosphoryl absorption shift constant. A similar result was obtained by Kagarise (29) for carbonyl compounds. While Burger's and Bell's correlations emphasized the role played by the solvent, the correlations found in this study were for many solutes in each of the two solvents, tributyl phosphate and tri-n-octyl phosphine oxide. Because the ionic potential and the grams of extractable species per 100 grams of complex for an inorganic nitrate in tributyl phosphate were related to the P —> 0 stretch frequency shift, an attempt was made to relate them to the distribution coefficient of the nitrate between tributyl phosphate and water. The distribution coefficient is defined as by the concentration of the nitrate in the organic phase/the concentration of the nitrate in the aqueous phase. Since the distribution coefficient of a nitrate between tributyl phosphate and water varies with both the concentration of the nitrate salt and nitric acid, the maximum distribution coefficient was used. The maximum distribution coefficient represents the highest value reported in the literature regardless of acidity or solute concentra­ tion (27,47). 68

Figure 8 shows a semilog plot of ionic potential versus the maximum distribution coefficient for various nitrate solutes in tributyl phosphate. An approximately linear relation was obtained. Figure 9 shows a semilog plot of grams of extractable species per 100 grams of complex versus the maximum distribu­ tion coefficient for various nitrate solutes in tributyl phosphate. An approximately linear relation was obtained. These correlations were made for the tributyl phosphate-nitric acid-metal nitrate system because -of the availability of the maximum distribution coefficients which in many cases resulted at high nitric acid acidities. 69

1000 —r~r is* '3- I ^14 •

100 I I

h 1.Co(N03)2 z y 10 lo­ 2.Zn(N03)2 o u. 3.Cu(N0 3)2 u_ g I 4.ca(n03>2 5. Cd(NO 3)2 1 6ce(n03)3 i- 3co 7Pr(N03)3 8.Nd(N03)3 o 9sm(n0^3 10. Fe (NO3)3 3 5 11. Y(N03)3 5 12.hf(n03)4

13. Th (N03)4

14. U0g(N03)2

15.Zr (N03)4

001

2- 3* 0001 '• i

IONIC POTENTIAL (CHARGE / IONIC RADIUS) Figure 8. Plot of ionic potential versus the maximum distribution coefficient for the tributyl phosphate-metal nitrate-nitric acid system 70

1000 15- /B.

12' 100

i.cofno^g

22n(N03)2 10' 3cu(n03)2

10 4.Ca(N0^2

5.Cd(N03)2

lj 6Ce(N03)3 y TPr(N0 ) LlLL. 3 3 LU &Nd(N03)3 o 9.fe(n05)3

K).Sm3

s M.Y(N03)3 m oc h- 12.hf(n05)4 V) q 13.U02(N03)2

s l4Zr(N03)4 3 1 l5Jh(N03)4 X <

001 4- /

0.001 _L!_L _L 10 20 30 40 50 GRAMS EXTRACTABLE SPECIES /100 GRAMS OF COMPLEX Figure 9< Grams of extractable species/100 grams of complex ifOTiana -kbo mavimum dl Rhr»1 huf-i on coefficient for the tri dutyj. pnos e—metal nitrate—nitric acid, system 71

ACKNOWLEDGMENTS

The author wishes to express his appreciation to Dr. Morton Smutz who suggested the problem and offered his guidance during the course of the work. The author would also like to express his appreciation to the Ames Laboratory and Chemistry infrared spectra groups for their part in obtaining the spectra of the various solute-solvent systems. 72

BIBLIOGRAPHY

1. Al cock, K., G-rimley, S. S., Healy, T. V., Kennedy, J., and McKay, H. A. C. The extraction of nitrates by tri-n-butyl phosphate (TBP). I. The system TBP + diluent + HgO + HNO3. Transactions of the Faraday Society 52: 39-47. 1956. 2. Baliah, V. and Subbarayan, P. The effect of solvent on the ultraviolet absorption spectra of phosphine oxide and sulfides. Journal of Organic Chemistry 25: 1833- I834. I960. 3. Banks, C. V., Spooner, J. L., and O'Laughlin, J. W. Differential spectrophotometric determination of neodymium in neodymium-yttrium mixtures. Analytical Chemistry 28: 1894-1897- 1956. 4. Banks, C. V., Spooner, J. L., and O'Laughlin, J. W. Differential spectrophotometric determination of rare earths. Analytical Chemistry 3°: 458-462. 1958* 5. Bauman, B. P. Absorption spectroscopy. New York, N. Y., John Wiley and Sons, Inc. 1962. 6. Bell, J. V., Heisler, J., Tannenbaum, H., and Goldenson, J. A linear phosphoryl absorption relationship. Journal of the American Chemical Society 76: 5185-5189» 1954. 7. Bellamy, L. J. and Beecher, L. The infra-red spectra of some organo-phosphorus . Journal of the Chemical Society 1952: 475-483. 1952. 8. Bochinski, J. H. Separation of individual rare earths by liquid-liquid extraction from multicomponent rare earth nitrates. Unpublished Ph.D. thesis. Ames, Iowa, Library, Iowa State University of Science and Technology. 1954. 9. Bostian, H. E. Mechanism of extraction of the rare earth nitrates by tributyl phosphate. Unpublished Ph.D. thesis. Ames, Iowa, Library, Iowa State University of Science and Technology. 1959» 10. Brand, J. C. D. and Cawthon, T. M, The vibrational spectrum of methyl nitrate. Journal of the American Chemical Society 77: 319-323. 1955. 73

11. Burger, L. L. The esters of the acids of phosphorus as solvents. U. S. Atomic Energy Commission Report HW-44888. [Hanford Works, Richland, Wash.]. 1957* 12. Cobb, C. E. [Infrared spectra of tributyl phosphate in water]. Unpublished work. [1955]• (Original not available for examination; cited in Transactions of the Faraday Society 52: 39-47. 1956). 13. Connick, R. E. and Hugus, Z. Z. The participation of f orbitals in bonding in uranium and the transuranium elements. Journal of the American Chemical Society 74: 6012 - 6015. 1952. 14. Dinnin, M. R. Equilibrium distribution studies of dysprosium nitrate-erbium nitrate-nitric acid-tributyl phosphate systems. Unpublished M.S. thesis. Ames, Iowa, Library, Iowa State University of Science and Technology. I960. 15. Ferraro, J. R. The nature of the nitrate in the TBP solvates MfNC^^TBP, M(N0])4'2TBP and M02(N03)2'2TBP. Journal of Inorganic and 10: 319-322. 1959. 16. Ferraro, J. R. The nitrate symmetry in metallic nitrates. Journal of Molecular Spectroscopy 4: 99-105» 1960. 17. Gatehouse, B. M., Livingstone, S. E., and Nyholm, R. S. Infrared spectra of some nitrato-co-ordination complexes. Journal of the Chemical Society 1957: 4222-4225. 1957- 18. Gaunt, J. and Meaburn, G. M. The infrared spectrum of tributyl phosphate and some possible impurities. United Kingdom Atomic Energy Authority Report AERE-CIR-785. [Gt. Brit. Atomic Energy Research Establishment, Harwell, Berks, England]. 1951* 19. Gillis, R. G., Horwood, J. F., and White, G. L. Bond refractions and the nature of phosphorus-oxygen bonds. Journal of the American Chemical Society 80: 2999-3002. 1958. 20. Healy, T. V. and McKay, H. A. C. Complexes between tributyl phosphate and inorganic nitrates. Recueil des Travaux Chimiques des Pays-Bas 75: 730-736. 1956. 74

21. Healy, T. V. and McKay, H. A. C. The extraction of nitrates by tri-n-butyl phosphate (TBP). II. The nature of the TBP phase. Transactions of the Faraday Society 52: 633-642. 1956. 22. Herzberg, G. Molecular spectra and molecular structure. II. Infrared and Raman spectra of polyatomic molecules. New York, N. Y., D. Van Nostrand Company, Inc. 1945. 23. Hesford, E. and McKay, H. A. C= The extraction of nitrates by tri-n-butyl phosphate (TBP). III. Extrac­ tion at trace concentrations. Transactions of the Faraday Society 54: 573-586. 1958. 24. Hesford, E., McKay, H. A. C., and Scargill, D. Tri-n-butyl as an extracting solvent for inorganic nitrates. IV. Thorium nitrate. Journal of Inorganic and Nuclear Chemistry 4: 321-325* 1957» 25. Horton, C. A. and White, J. C. Infrared spectra of some organo-phosphorus extractants. Talanta 7* 215-231. 1961. 26. Horton, C. A. and White, J. C. Infrared study of some phosphine oxide adducts. Pittsburg Conference on Analytical Chemistry and Applied Spectroscopy Abstracts I960: 57» I960. 27. Ishimori, T. and Watanabe, K. Inorganic extraction studies on the system of tri-n-butyl phosphate-nitric acid. Bulletin of the Chemical Society of Japan 33s 1443-1448. i960. 28. Jensen, V. K. A. Dipolmomente der hô'heren isologen der suifoxyde und aminoxyde. Zeitschrift ftir anorganische und allgemeine Chemie 250: 268-276. 1943» 29. Kagarise, R. E. Relation between the electronegativities of adjacent substituents and the stretching frequency of the carbony1 group. Journal of the American Chemical Society 77: 1377-1379. 1955- 30. Katzin, L. I. Infra-red spectra of nitrate salts in tributyl phosphate solution. Journal of Inorganic and Nuclear Chemistry 24: 245-256. 1962. 75

31. Katzin, L. I. Infra-red spectra of water in tributyl phosphate containing dissolved salts, and the effects of solutes on the trialkyl phosphate spectrum. Journal of Inorganic and Nuclear Chemistry 20: 300-303» 1961. 32. Katzin, L. I., Ferraro, J. B., Wendlandt, W. W., and McBeth, B. L. The relations of thorium nitrate and certain organic solvents ; the coordination number of Th^*. Journal of the American Chemical Society 78: 5139 - 5144. 1956. 33* Kinney, P. J. An infrared study of the TBP-HNOo-HgO solvent extraction system. Unpublished typewritten preliminary report. Ames, Iowa, Chemical Engineering Department, Iowa State University of Science and Technology. 1962. 34. ICnapp, L. L., Smutz, M., and Spedding, F. H. Solvent extraction equilibria for rare earth nitrate-tributyl phosphate systems. U. S. Atomic Energy Commission Beport ISC-766. [Ames Lab., Ames, Iowa]. 1956. 35» Majumdar, S. K. and De, A. K. Liquid-liquid extraction of iron (III) with tributyl phosphate. Talanta 7$ 1-6. I960. 36. Manning, P. G. The extraction of thorium and some lower lanthanide nitrates by dibutyl butyl phosphonate. Canadian Journal of Chemistry 40: 1684-1689. 1962. 37» McKay, H. A. C. and Healy, T. V. Tri-n-butyl ortho- phosphate (TBP) as an extracting solvent. In Bruce, F. B., Fletcher, J. M., and Hyman, H. H., eds. Progress in Nuclear Energy, Series III. Process Chemistry. Volume 2. pp. 546-556. New York, N. Y., Pergamon Press. 1958. 38. Moeller, T. Inorganic Chemistry. New York, N. Y., John Wiley and Sons, Inc. 1959. 39. Nukada, K., Naito, K., and Maeda, U. On the mechanism of the extraction of uranyl nitrate by tributyl phosphate. II, Infrared study. Bulletin of the Chemical Society of Japan 33* 894-898. i960. 76

40. Oshima, Keiichi. Solvent extraction of metals by organophosphorus compounds. II. Particular extraction systems. Japan Atomic Energy Research Institute, Tokyo. Nippon Genshiryoka Gakkaishi 4: 166-174. 1962. 41. Peppard, D. F., Driscoll, W. J., Sironen, R. J., and McCarty, S. Nonmonotonic ordering of lanthanides in tributyl phosphate-nitric acid extraction systems. Journal of Inorganic and Nuclear Chemistry 4: 326-333* 1957 - 42. Peppard, D. F., Faris, J. P., Gray, P. R., and Mason, G. W. Studies of the solvent extraction behavior of the transition elements. I. Order and degree of fractionation of the trivalent rare earths. Journal of Physical Chemistry 57: 294-301. 1953* 43* Peppard, D. F. and Ferraro, J. R. An infrared study of the svstems tri-n-butyl phosphate-HNO3 and bis-(2-ethyl- hexyl)--HNO^. Journal of Inorganic and Nuclear Chemistry 15: 365-370. I960. 44. Peppard, D. F., Gray, P. R., and Markus, M. M. The actinide-lanthanide analogy as exemplified by solvent extraction behavior. Journal of the American Chemical Society 75: 6063-6064. 1953. 45. Peppard, D. F., Mason, G. W., and Maier, J. L. Inter­ relationships in the solvent extraction behavior of scandium, thorium, and zirconium in certain tributyl phosphate-mineral acid systems. Journal of Inorganic and Nuclear Chemistry 3: 215-228. 1956. 46. Sato, T. The back extraction of uranyl nitrate from tributyl phosphate solution. Journal of Inorganic and Nuclear Chemistry 7: 147-149. 1958. 47. Scargill, D., Alcock, K., Fletcher, J. M., Hesford, E., and McKay, H. A. C. Tri-n-butyl phosphate as an extracting solvent for inorganic nitrates. II. Yttrium and the lower lanthanide nitrates. Journal of Inorganic and Nuclear Chemistry 4: 304-314. 1957. 48. Schoenherr, R. U. Prediction of equilibria for rare earth nitrate-nitric acid-tributyl phosphate systems. Unpublished Ph.D. thesis. Ames, Iowa, Library, Iowa State University of Science and Technology. 1959. 77

49. Sharp, B. M. Equilibrium of the system lanthanum nitrate- praseodymium nitrate-nitric acid-water-tributyl phosphate. Unpublished M.S. thesis. Ames, Iowa, Library, Iowa State University of Science and Technology. I960. 50. Specker, H. and Cremer, M. Uber eisen (Ill)-verbindungen in chloridhaltigen Verteilungssystemen. Tresenius' Zeitschrift fCir analytische Chemie 16?: 110-114. 1959» 51. Sugden, S., Reed, J. B., and Wilkins, H. The parachor and chemical constitution. I. Polar and non-polar valencies in unsaturated compounds. Journal of the Chemical Society 12?: 1525-1540. 192$. 52. Von Hippel, A. R., ed. Molecular science and molecular engineering. New York, N. Y., John Wiley and Sons, Inc. 1959. 53* Vratny, F. Infrared spectra of metal nitrates. Applied Spectroscopy 13: 59-70. 1959. 54. Warf, J. C. Extraction of cerium (IV) nitrate by butyl phosphate. Journal of the American Chemical Society 71: 3257-3258. 1949. 55* Wendlandt, W. W. and Bryant, J. M. The of some metal nitrate salts in tri-n-butyl phosphate. Journal of Physical Chemistry 60: 1145-1146. 1956. 56. White, J. C. and Ross, W» J. Separations by solvent extraction with tri-n-octyl phosphine oxide. U. S. Atomic Energy Commission Report NAS-NS-3102. [National Academy of Sciences]. 1961. 78

APPENDIX Figure 10. Infrared spectrum of purified TBP, NaCl cell

Figure 11. Infrared spectrum of purified TBP, servofrax cell

Figure 12. Infrared spectrum of purified TBP, equilibrated with water, servofrax cell 80

FREQUENCY (CM1) 2000010000 50001000 3000 2600 2000 1800 1600 1*00 1200 1100 1000 950 900 850 800 750 100 W3 — 80

£60

:io

! 20

- 0; 7 é » 11 12 13 WAVELENGTH (MICRONS)

WAVELENGTH (MICRONS) 2.5 6 7 10 11

, , "X , i , .

- 60 / k . V • - ! ; i | 2 i fc<0 r i • . \ i i i 4 : ! i 1 • J • t •! i r i i 1 : 20 j ...... i. ..L ! i "I" - r T' t / T !- 1 V ! \ >v V - • - ... .) ! — VJ u 1 T i- -I- + I- -0 ' i" t 4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM')

WAVELENGTH (MICRONS) 23 6 7 10 11 100 rfiO 3 — 60

: 40 m

: 20 e si

4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CMJ) Figure 13• Infrared spectrum of 0.52 normal HNOo in water equilibrated-purified tbp, servofrax cell

Figure 14. Infrared spectrum of 1.36 normal HNO3 in water equilibrated-purified TBP, servofrax cell

Figure 15* Infrared spectrum of 2.72 normal HNO3 in water equilibrated-purified TBP, servofrax cell 82

WAVELENGTH (MICRONS) Ï

4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM ')

WAVELENGTH (MICRONS)

4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM ')

WAVELENGTH (MICRONS)

4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 FREQUENCY (CM4) Figure 16. Infrared spectrum of 4.4 normal HNO3 in water equilibrated-purified TBP, servofrax cell

Figure 17- Infrared spectrum of 5*1 normal HNO3 in water equilibrated-purified TBP, servofrax cell

Figure 18. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of J.l molar HNCH-2.68 molar UOgfNO^g, servofrax cell 84

WAVELENGTH (MICRONS) 6 7

II

4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM ')

WAVELENGTH (MICRONS) 6 7 8 9 10 11

4000 3500 3000 ,2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM ')

FREQUENCY (CM1) 10000 5000 4000 3000 2500 . . .2000 1800 1600 ..i.. 1400 1200 1000 950 900 850 800 750 100 i t T <- -I- • — T - - -1- i k/ \k "1" " ! ~*k* - I j-- ! i • 4 I Y i H- ! 1 BO V\ ! i i M - I- t " . 1 JT ' i. -1 A: ! -I 1- - - | - 1 s 60 i "t- -j 1 I i" 4. I i .! -i- - j— -!- 4 • T ; - -! : i s /r .... y i ...j.. : ; £40 i _ j- -t- 4- -• j— • • z J i —j— i4- i y • - : 20 ! - — —f- -f- - • !"' J r - / "Vy ' j- +- -} • ~l" —h"Ijl -1-- ~~r~ "t" 1 • i 7 8 9 10 11 12 13 1. WAVELENGTH (MICRONS) Figure 19. Infrared spectrum of 0.13 molar U02(N03)2 in water equilibrated-purified TBP, servofrax cell

Figure 20. Infrared spectrum of 0.44 molar UO^(NO^)^ in water equilibrated-purified TBP, servofrax cell

Figure 21. Infrared spectrum of 0.91 molar UOgfNO^g in water equilibrated-purified TBP, servofrax cell 86

WAVE NUMBERS IN CM ' 5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 1000 900 100

= 60

S 40

WAVE LENGTH IN MICRONS

WAVE NUMBERS IN CM ' 5000 4000 3000 2500 2000 1500 1400 1300 1200 moo 1000 900 100

S 60

2 3 4 5 6 7 9 10 12 WAVE LENGTH IN MICRONS

WAVE NUMBERS IN CM' 5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 1000 900 100

I !î o

2 3 4 5 6 7 8 9 10 12 Figure 22. Infrared spectrum of 1.0 molar UOg(NO^)2 in water equilibrated-purified TBP, servofrax cell

Figure 23. Infrared spectrum of saturated in water equilibrated-purified TBP, servofrax cell 88

WAVE NUMBERS IN CM-' 5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 100

5 6 7 WAVE LENGTH IN MICRONS

WAVE NUMBERS IN CM ' I00r5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 1000

f ir 1 o V

!.. A I 1I 1 Ij ! 1 1 ! \ I s ! \ / 1) 1 1 1

j |

5 6 7 10 ii WAVE LENGTH IN MICRONS Figure 24. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of 3.1 molar HNO3-I.34 molar 1102(1^03)2, servofrax cell

Figure 25. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of 3*1 molar HNO3-O.268 molar 1102(1^0^)2, servofrax cell

Figure 26. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of 7.8 molar HNO3-I.68 molar 1102(1^03)2, servofrax cell 90

FREQUENCY (CM1) 10000 5000 4000 3000 2500 . , 2000.1800 , 1600 . 1400 .1200 , 1000 950 900 850 800 100 L~r i . - j- - -f -- • V" -f - ; ; 4- A f- ! ! i __L L- 1 —i__ J. I ; — —r~ — - I •• r g 80 , \ — i j ™r / .I. r V A 1 ( t -I-- r • -\- -j... ..I ! L --L L ! 1 !-!- -f--r -~h- i i - - - f i . j. i -> 1 L -u - •- ... ! A - ~\ — * - • A - / \ /1 i -i .1 —t— —r— ; 1 J- 1 ' "i " -j- - \l f"t i i L ... • *r -!-• 4- • : • - —r

t ! ' • ! ' • ! * • -• * i i

7 8 9 10 11 12 WAVELENGTH (MICRONS)

FREQUENCY (CM') 5000 4000 ' 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800

2

7 8 9 10 11 12 i: WAVELENGTH (MICRONS)

FREQUENCY (CM') 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800 100 *•- -! t - '\ : p 80 s/\ I\ f.L •A fi y ... ^60 * f\ ~r — A: 1 - - i— - ' _ l__ ...... i" V — - / i i. ---- -•— —r-— - • - -f- — •• e20 ; v — TV V— - ; - -t-l -i- - - -- —- - — i _i_j 11- V V -4- ! • _L_ ! 3 4 6 7 8 9 10 11 12 WAVELENGTH (MICRONS) Figure 2?. Infrared, spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of 4.51 molar HNO3-I.68 molar UO2()2» servofrax cell

Figure 28. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of 1.13 molar HNO3-I.68 molar UO2(NO-^ ) 2> servofrax cell

Figure 29. Infrared spectrum of saturated UC^CNO^)2 in twenty percent TBP in CCl^, NaCl cell 92

FREQUENCY (CM ') 10000 5000 4000 3000 2500 . 2000 1800 1600 1400 1200 1000 950 900 850 800 100

V-

7 8 9 10 WAVELENGTH (MICRONS)

FREQUENCY (CM') 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800 100 1 p80 1 I.

T ft -60 \ y x- - ! - - - J z< 1 : 40 ! / A - :•*

! - • - _j. . • : 20 A , '

• / \ f 1-- \

1 2 3 4 5 6 7 8 9 10 11 12 I: WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 80 100,"

WAVELENGTH (MICRONS) Figure ]0. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of one-third saturated UOgClg, servofrax cell

Figure 31. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of one-half saturated UOgClg, servofrax cell

Figure 32. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of saturated UOgClg, servofrax cell 94

WAVELENGTH (MICRONS)

1700 1600 1500 1400 FREQUENCY (CM ')

WAVELENGTH (MICRONS) 2.5 6 7 10 11 —1 ... 100 - J- —i— —f-h • 1 • -ft- i • ! 1I I -, 1 ! ! X VA A 1 ! 1 : 80 • j • I 4 —1IV, ! * • ll i- -60 * ' j : -> I I ' ) 1 ! / j l: | - -• 1 . —o- • i 4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM ')

WAVELENGTH (MICRONS)

4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM ') Figure 33* Infrared spectrum of nearly saturated UOgClg in twenty percent TBP in CCl^, NaCl cell

Figure Infrared spectrum of saturated UOgfClO^jg in- purified TBP, servofrax cell

Figure 35* Infrared spectrum of saturated Th(NO^)^ in twenty percent TBP in CCl^, NaCl cell 96

FREQUENCY (CM') 2000010000 5000 «00 3000 2500 2000 1600 1600 1/00 1200 1100 1000 950 900 850 800 100}--

60--

WAVELENGTH (MICRONS)

FREQUENCY (CM1) 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800 7 1 • ! i • . 1- j • ; 1 1 i f' • j . i. A -!- • - -* - r - t • P \ _i_. -! • i ,4- —j J _ 1 L (' ~ —r— —•— ;\ -f- : ! ^ -A "* " -r I Vi- • ! ; : / f\\ • / - —p. _i_. - f— V- -i j • j i v . L i / -r • r ,_i - , 1" j : • i - r - r f - . p. • \jV • —• — - -!- . j„ ... :• ! • ...j. "i" • ;

1 2 3 4 5 6 7 8 9 10 11 12 13 WAVELENGTH (MICRONS)

FREQUENCY (CM') ZOOM 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 100-

WAVELENGTH (MICRONS) Figure 36. Infrared spectrum of 0.12 molar Th(NO^)^ in water equilibrated-purified TBP, servofrax cell

Figure 37• Infrared spectrum of 0.44 molar Th(NO^)^ in water equilibrated-purified TBP, servofrax cell

Figure 38. Infrared spectrum of 0.82 molar Th(NO^)^ in water equilibrated-purified TBP, servofrax cell 98

1 WAVE NUMBERS IN CM ' 5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 1000 900 too

s 40

2 3 4 5 6 7 8 9 10 12 WAVE LENGTH IN MICRONS

WAVE NUMBERS IN CM ' 5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 1000 900 100

eo

= 60

5 40

2 3 4 5 6 7 8 9 10 12 WAVE LENGTH IN MICRONS

WAVE NUMBERS IN CM * 5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 1000 900

Ik! J : a/- 1 / 1 1 ! 1 / 1 A f l \ / Ui UK 1 / 1 W \ ] 11 i U1 1

v ! v : i ; i ; ' 1 ! ! 2 4 5 > 7 0 ° 'v :: ; VVAvc LcfNtoi M Ih MICRONS Figure 39* Infrared spectrum of 1.01 molar Th(NO^)^ in water equilibrated-purified TBP, servofrax cell

Figure 40. Infrared spectrum of saturated Th(NO^)^ in water equilibrated-purified TBP, servofrax cell 100

WAVE NUMBERS IN CM ' 5000 4000 1500 1400 1300

5 6 7 WAVE LENGTH IN MICRONS

WAVE NUMBERS IN CM-' 5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 100 r

5 6 7 10 ii 12 WAVE LENGTH IN MICRONS Figure 41. Infrared spectrum of water equilibrated-purified TBP which was contacted with concentrated HNO3 and then saturated with Th(NO^)^, servofrax cell

Figure 42. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of saturated Pr(NOg)., servofrax cell J *

Figure 43* Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of 3*84 molal Pr( 1^03)3-6.3 molar HNO3, servofrax cell 102

FREQUÈNa (CM1) 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800

WAVELENGTH MICRONS)

FREQUENCY (CM ') 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800 100 i - i - 1 1 r •>> v y i _ V - - i. ' . 4: v\ ; i 4" V / ; 1 • •*- - W i v 1 -!•- •• f - 1 _ /• A VI,.-Il 7 4- — — -L_ -- 1 ; h-l H- A .M / i .y... V 1. . r • - ~i 1/ "Vi V\ - i" ! .... , i "p - i -r -| v/ -i 4' - .L ...... i r A ..j. : •J V7 f1 —j— — - —p V Vu !

7 8 9 10 WAVELENGTH (MICRONS)

FREQUENCY (CM') 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800

7 8 9 WAVELENGTH (MICRONS) Figure 44. Infrared spectrum of 0.13 molar SmtNO^)^ in water equilibrated-purified TBP, servofrax cell

Figure 45» Infrared spectrum of 0.5 molar SmtNO^)^ in water equilibrated-purified TBP, servofrax cell

Figure 46. Infrared spectrum of 0.9 molar SmtNO^)^ in water equilibrated-purified TBP, servofrax cell 104

WAVE NUMBERS IN CM-' 3000 2500 2000 1500 1400 1300 1200 MOO

5 6 7 WAVE LENGTH IN MICRONS

WAVE NUMBERS IN CM ' 100-5000 4000 3000 2500 1500 1400 1300 1200 1100

• " 1 / v\

|60 ,h i) Z < y f

Î v | v 5 6 7 WAVE LENGTH IN MICRONS

WAVE NUMBERS IN CM ' 5000 4000 3000 2500 2000 1500 1400 1300 1200 1100 j ! ! _ _ i ; I ! i u z 5 j L \ If i 2 ! j ! 11 1 I 1

! ! y vu i WAVE LENGTH IN MICRONS Figure 47* Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of 3*2 molal PrGto^)3-3*1 molar HNO3, servofrax cell

Figure 48. Infrared spectrum of water equilibrated-purified TBP which was contacted with an initial aqueous concentration of 2.68 molal ~Pr(Wj)^-$.2 molar HNO3, servofrax cell

Figure 49• Infrared spectrum of nearly saturated LaCNO^)3 in twenty percent TBP in CCI4, NaCl cell 106

FREQUENCY (CM') 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800 100 - ;- - *• - - • —

_L. \ / p 80 r\ •j v \ ' \ . • ,\ • ,-v /rx — 60 .1 <- x : — - ! -! z r+> < Z IO r' ; I V i / : \J j II • S 20 / ! l I 0- 7 8 9 10 WAVELENGTH (MICRONS)

FREQUENCY (CM') 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800 100 ! |• :

/" -80 A • v.. I V ' \i V ; • V— > •V -i ! — 60 / A . ... 1/--t- - -> Z r. y\ \:/ | 40 \ / V. y vV £ 20 / •V V/

7 8 9 10 12 13 vjuav/ci cki/itu /iiiroryuc\

FREQUENCY (CM') 2000010030 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 80

%

8 9 10 11 WAVELENGTH (MICRONS) Figure 50. Infrared spectrum of nearly saturated Ce(N0^)o in twenty percent TBP in CCl^, NaCl cell

Figure 51» Infrared spectrum of nearly saturated Pr(NOo)o in twenty percent TBP in CCl^, NaCl cell

Figure 52. Infrared spectrum of nearly saturated Nd(N0o)o in twenty percent TBP in CCl^, NaCl cell 108

FREQUENCY (CM') 2000010000 5000-1000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

* 10 WAVELENGTH (MOONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

9 10 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 100-— r-80h-

10 WAVELENGTH (MICRONS) Figure 53* Infrared spectrum of nearly saturated Sm(NOn)o in twenty percent TBP in CCl^, NaCl cell

Figure 54. Infrared spectrum of nearly saturated Eu(NOo)o in twenty percent TBP in CCl^, NaCl cell

Figure 55* Infrared spectrum of nearly saturated Gd(NOo)o in twenty percent TBP in CCl^, NaCl cell 110

FREQUENCY (CM1) 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

7 8 9 10 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1400 1400 1200 1100 1000 950 900 850 800

1 8 9 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

a 9 io WAVELENGTH (MICRONS) Figure 56. Infrared spectrum of nearly saturated Tb(NOo)n in twenty percent TBP in CCI4, NaCl cell

Figure 57• Infrared spectrum of nearly saturated Dy(NCL )^ in twenty percent tbp in CCl^, NaCl cell ^

Figure 58. Infrared spectrum of nearly saturated Ho(NOo)o in twenty percent TBP in CCl^, NaCl cell 112

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1400 1400 1200 1100 1000 950 900 850 800

9 10 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

l i • ! 4-IP" /> i 1 i I ! H -f —t— i J jv- i i !# ! )

• 1— VJ— :

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 —- —* . •k. FfF -••I- . .. . y\ -/ f y i Vv\ A t ,r i i- ; -r-i- j P\~

...... • "! —r— ...... L^_

• t .. . ; .. -r- :• • • . * r—' —- WAVELENGTH (MICRONS) Figure 59» Infrared spectrum of nearly saturated Er(NOo)A in twenty percent TBP in CCI4, NaCl cell

Figure 60. Infrared spectrum of nearly saturated Tm(NOo)o in twenty percent TBP in CCl^, NaCl cell

Figure 61. Infrared spectrum of nearly saturated YbfNO^)^ in twenty percent TBP in CCl^, NaCl cell 114

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

: - —\ i - 1 —r——-J •_ • i : j" I • "••I • f • Ti ! i f \ "i. ' I ' 1 ' , I ' • i ! |...... | . Ayv! .. \n . 1 1 • : " v • ; " • ; r : f \ ...... i . . .. • • . : . j. V, • ' .. : >\ j • . : ...... r i 1 •: • • t- 1 i - ; • •• \ / •

- m WAVELENGTH (MICRONS)

FREQUENCY (CM ) 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 600 1 h- : ; —1—

. ~i 1 . .. rr s i ' I f / V • ..... A\ ! 1.:.... / . i ; i i : — L_L_ i „ : ' V 1 ! ! . i i ? ; ; " ""T" '

!•

— — - 1 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

9 10 WAVE1EMGTH (MICRONS) Figure 62. Infrared spectrum of nearly saturated Lu(N0o)c in twenty percent TBP in CCl^, NaCl cell

Figure 63. Infrared spectrum of nearly saturated Y(N0o)o in twenty percent TBP in CCl^, NaCl cell

Figure 64. Infrared spectrum of saturated Fe(NOo)o in. twenty percent TBP in CCI4, NaCl cell 116

FREQUENCY (CMJ) 2000010000 5000 4000 3000 2500 2000 1800 1600 140C 120Û 1100 1000 950 900 850 800 f— 1 1 - ; ' i - | T~! ! L.J/;,... i 1 , r\ /> ' •: ! i. . 1 I 1 U m h A A r— 1 :b k ! r —: ...t.... v 4 - » • ! ' I ' ' t

...... L._ : i ^ ' 1- — WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 LECO 1400 1200 1100 1000 950 900 850 800

—80 —-

10 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 loor r~ . —1 i ! ! • ! 1 . i ! . i 1 • | • ! • ( i M W -so 1 : ! ! y\ • ! ! 1 zi nit l\ | 1 i. f T ii ! • ! ' J • j ;• ; 1 M £.60- \ A J.. .i i \ L \ ! ! • !- •TT- i f! \ / III!' • ; 1 ! 1 - ' '! il ! • 1*1TT 1 ! !< .....| ...... |... i r .. j . : j . j / \ Y ...j...... j... \\ { p20i- • r ' !, ' Ii ~1, • i Î ' I •• • •• j • - • r | I- V ..\j ! j | ' !" —1— J ..... i,. 'I'M ! -4— -V. WAVELENGTH (MICRONS) Figure 65. Infrared spectrum of saturated FeCl^ in twenty percent TBP in CGl^, NaCl cell

Figure 66. Infrared spectrum of saturated Cu(NO^)^ in twenty percent TBP in CCl^, NaCl cell

Figure 67. Infrared spectrum of saturated Cd(NO^)^ in twenty percent TBP in CCl^, NaCl cell 118

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 . 1000 950 900 850 800 100: rsd— • : ' : !.. j -T- j— %- r N 1 • 1 : ( : j • •I -80' VIM" 1 i - 1 ' A r 1 Ï .. : | . i. . — 60' i • • 1 1 A • i / ^ i — \r M ! T 40 . ii 5 i i1 • • [ § M • i — \L " 20 i • —V 1 i • l=j=

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850

Q. - 7 8 9 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2C00 1800 1600 1400 1200 1100 1000 950 900 850 600 too':

7 8 » WAVELENGTH (MICRONS) Figure 68. Infrared spectrum of saturated Ca(MO^)2 i% twenty percent TBP in CCl^, NaCl cell

Figure 69» Infrared spectrum of saturated Zn(N0^)£ in water equilibrated-purified TBP, servofrax cell

Figure 70. Infrared spectrum of nearly saturated Ba(SCN)2 in water equilibrated-purified TBP, servofrax cell 120

FREQUENCY (CM1) 2000010000 50C0 4000 3000 2500 2000 1800 1600 WOO 1200 1100 1000 950 TOO 850 800 100-

7 8 9 10 WAVELENGTH (MICRONS)

FREQUENCY (CM1) 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800 100

WAVELENGTH MICRONS)

FREQUENCY (CM') 10000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1000 950 900 850 800 7 100 r I . nr g 80 . \ 1 A

— 60 V ... - • < j r - - ! / - / - -- " 'f r2 20 — - - - —r ~ •- - f- V ...... i_ - --- ™h- —p- - i ' • ' i 7 8 9 10 12 WAVELENGTH (MICRONS) Figure 71. Infrared spectrum of nearly saturated Sr(SCN)2 in water equilibrated-purified TBP, servofrax cell

Figure 72. Infrared spectrum of solid Fe(HO^)^, NaCl cell

Figure 73» Infrared spectrum of 0.1 molar TOPO in CCl^, NaCl cell 122

FREQUENCY (CM ') 10000 5000 4000 30C0 2500 . . .2003 1800 1600 , 1400 1200 1000 950 900 850 800 100 a. -I — —1— i i i 1 . r 1 r~ -|- ™r -r i i -f -4~ V -.1- . ! i- 1- - i~ T' i\f Nr 4--h -i i 80 ,._L- \i . i ' —T— -V f ~h 1 > vh +- ir 4--N ! - — -1- /-!— -p " " - j- \ ~ 1 r y- -f- + i "P — 60 .....i j - _u. -J— - -j- 1 . s ' I • -i- -4 -l- 4- 1 < -j- - : - ~Ι -l\-_ !... .„!/ .. --i - 4- - ... 1 11 | -- / i' ~v 4 V i -i ...j 4- ' - t- ..{... 'f---- •!- "T" I- / , 1 7 c _!_ ; -i- —t— 1- + l_ N- : -• - —|- - -!- -!- t 4- 4 — -t- 7 8 9 10 12 WAVELENGTH (MICRONS)

FREQUENCY (CM') 20GC010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 80 100

7 8 » 10 -— WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5C00 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 80

7 Ô T WAVELENGTH (MICRONS) Figure ?4. Infrared spectrum of 0.1 molar TOPO which was contacted with an initial aqueous concentration of 0.00735 molar U02(N0^)2, NaCl cell

Figure 75- Infrared spectrum of 0.1 molar TOPO which was contacted with an initial aqueous concentration of 0.0296 molar UOgCNO^^i NaCl cell

Figure 76. Infrared spectrum of 0.1 molar TOPO which was contacted with an initial aqueous concentration of saturated UO^CNO )^, NaCl cell 124

FREQUENCY (CM1) 2000010000 5003 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

5 6 7 8 10 11 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 ! 1 A, ! L • ... . .1.. .. 1 î\ ) - j- „ ' : !£-60 1 •Mfl An /I fV !

Jl |I 40 . .1..

; • i2o ' ! • : i 1 " ;•••• ..j.. •' .j. . • ' !

. 1 • » —h —

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2003010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

WAVELENGTH (MICRONS) Figure 77* Infrared spectrum of nearly saturated UOoClp in 0.1 molar TOPO in CC14, NaCl cell

Figure 78. Infrared spectrum of nearly saturated UOgfClOnJn in 0.1 molar TOPO in CCl^, NaCl cell

Figure 79. Infrared spectrum of nearly saturated Th(N0~K in 0.1 molar TOPO in CCl^, NaCl cell 126

FREQUENCY (CM') 20000 LOCOO 5000 4COO 3000 2500 2000 1800 1600 , WOO 1200 1100 1000 950 900 850 800 100?" i l-H— ... : ! !' | !' i 7\/T~n : • 1 • ' •i i/ : ; !.. . t i 'j*. n - c-eo"r , I • i - n// > V i 'A / ' 'V' s i ii -i • i ' • ! W\\ • ! i 1 1 1 1 • 1 7! V 1 i '60r i j ; i • !" 1 ! • I ' z ! 1 ' < . ! . I . - !.. ! ! : 40:- i • i i : . i T~" • • i • i ; ; i " i Z < ! : I ! i i '! j • ! : : 20'- •••i V .. • 1 • 1 1 MH ' 1 • i - • • ! : i . - o% i i I i ! 1 ' 1 • ! • WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 . 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 )00::

7 b 10 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 -LOCO 3000 2500 2000 1800 1600 U00 1200 1100 1000 950 900 850 SCO 100:

0 7 8 9 WAVELENGTH (MICRONS) Figure 80. Infrared spectrum of nearly saturated Ce(N0o)o in 0.1 molar TOPO in CCl^, NaC1 cell J

Figure 81. Infrared spectrum of nearly saturated Pr(N0^)o in 0.1 molar TOPO in CCI4, NaCl cell

Figure 82. Infrared spectrum of nearly saturated Nd(N0o)~ in 0.1 molar TOPO in CCI4, NaCl cell J J 128

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1600 1600 14:0 1200 1100 , LOOO 950 900 850 800 r

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 IQOO 950 900 850 800

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 /000 3000 2500 2000 1800 1600 1400 1200 1100 JOOO 950 900 850 800

7 8 I 10 WAVELENGTH (MICRONS) Figure 83• Infrared, spectrum of nearly saturated Sm(NOn )^ in 0.1 molar TOPO in CCl^, NaCl cell J J

Figure 84. Infrared spectrum of nearly saturated Fe(NOo)o in 0.1 molar TOPO in CCl^, NaCl cell J J

Figure 85. Infrared spectrum of nearly saturated FeClo in 0.1 molar TOPO in CCI4, NaCl cell 130

FREQUENCY (CM') 2000010000 5000I— /000 : ! 30001 2500I i 20001 1800i 1 1600 1400 1200 1100 1000 950 900 850 800 : • I ! • '!••!• • 1 ! • ! • j ' ! if. i : | „A'i' • ! : rT^ J • ! • un i i ! M I r; i ! !• ! • 1 1 V 1 ; i ! ! ' " i /! ^ 1 1 : i i i • ! ! • . ! • ! 1 : ! i 1 I ! j - 11 i 1 Vi i V 1 ; ] ! i i •• • | • j i ! ! • : r; i ~r 'Ml ! • i • j ; i

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2ÛC0010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 ICO

60

40: .1—

WAVELENGTH (MICRONS)

, FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

WAVELENGTH (MICRONS) Figure 86. Infrared spectrum of nearly saturated ZrCNOoK in 0,1 molar TOPO in CCl^, NaCl cell

Figure 8?» Infrared spectrum of nearly saturated Hf(NOo)/, in 0.1 molar TOPO in CCI4, NaCl cell J

Figure 88. Infrared spectrum of nearly saturated H^CefNOc)^ in 0.1 molar TOPO in CCI4, NaCl cell 132

FREQUENCY (CM') 20CÛ010000 5000 4000 2000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 B50 800 100:

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 650 GOO loo:

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 600 1 X f i . 1 : i • j • • i L_i . . ; ; ; ! 1 i i ; i :i H • 1 . • i \ If ! : i ! A/1 A i1 I/ • 1 • i . 1 hi' \ 1 ( : | ' 1 ' ! ' ' ? 1 : : | i • 1/ / r/ "j : i 1 ! ! " 1' : ' 1' - j, t I . ... ! i T L±i__ - -U] I . WAVELENGTH (MICRONS) Figure 89- Infrared spectrum of nearly saturated Zn(N0~)2 in 0.1 molar TOPO in CCl^, NaCl cell J

Figure 90. Infrared spectrum of nearly saturated Cd(N0o)2 in 0.1 molar TOPO in CCl^, NaCl cell

Figure 91. Infrared spectrum of nearly saturated SnClk in 0.1 molar TOPO in CCl^, NaCl cell 134

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

W

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

T 40—

7 8 9 10 WAVELENGTH (MICRONS) Figure 92. Infrared, spectrum of nearly saturated CoCNOo)? in 0.1 molar TOPO in CCl^, NaCl cell J

Figure 93* Infrared spectrum of nearly saturated CoCl^ in 0.1 molar TOPO in CCl^, NaCl cell

Figure 94. Infrared spectrum of methyl isoamyl ketone, servofrax cell 136

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 100

T40:-

WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 .. j I • • ! ,, 1 ! ! ; • ! \lJ — ! i i • ; i f i • ! ; i • i : j • ! ! 1 ! j • Ï i ! i • ' ! : 1 i ! I i J i • 1 • i . , — ! i i • \ I . i ! ' i 1 | • : i : ! 1 1 ; ! ! ' ' 1 h=t=d î_ : WAVELENGTH (MICRONS)

WAVELENGTH (MICRONS) 2.5 100

4000 3500 3000 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 FREQUENCY (CM ') Figure 95» Infrared spectrum of saturated UC^CNO^^ in methyl isoamyl ketone, servofrax cell

Figure 96. Infrared spectrum of saturated UOgClg in methyl isoamyl ketone, servofrax cell

Figure 97* Infrared spectrum of saturated ThfHO^)^ in methyl isoamyl ketone, servofrax cell 138

WAVELENGTH (MICRONS) 2j 6 7 10 11 100 i— — — .. —— - * * r- - ~r - j- - « -

• —— . — 80 ... j ; % 1 — . j.:. A \i ^ 60 — : r --- —- • — " • i- • I • - -i v * v/ < -L- : 40 i 1 ..... — y -- -r • - "p "* — .... l/l ' 1 \ — - - - ' '' y[-]\ ' —- t - - : 20 /S . a) "Î" - - r • —Hi" r v if 17 /v v — X/ J. ... - -r~ —- \J> 1 ~ r 4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM')

WAVELENGTH (MICRONS) 2.5 6 7 10 11 100 , S - — T7~* si" \l — : V — •— *\ —- v (- -• *- ' - r — ir C" 80 */ v h -- —~ L X' /."\ / i ' ' j -r~ -r- • "V ' --60 \ J 7 li ... ^. 1 /'• .1 u V "j" - " -r- / M i _r < \ • -r- — — :• V' * -1 : ! : 40 /I ! / -1- *- "" -r* —p -r - • /TV ' r 1~ i —t— i — - p T " i- -i- --- _P ; --T T SÎ 20 1 T 1 -p 4- u. -L "I • T Ir * ~r "T -;r A 1 -~T 4 -J- T i i _p -r- -r~ -!- - •- ~h -j- ! -f- •; - 1 • 4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM')

WAVELENGTH (MICRONS) 2-5 6 7 10 11 100 ... . - » • ..... — . i r-i-r- . 1 . I1 . ! . I .. • 1 • V, r 80 i——( . . . \ 1 i • 1 ' r\ (\ \ /1 F v|. — 60 ••i • 1 'I 'J ' 7 .... •\ l\ • -• i ' i- /! • i • ! . \ yy —- — • — -• •- 1/- A-V • i — — — L —- — — -- - H \ / V \ — — — — —- — — — — ... — —- — — —- -i- __ — 1 • - • I 20 — — .... — — — — - —• — - -r- — • -

— — — -f- — —— —1— — -r~ . —- 4000 3500 3000 2500 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 FREQUENCY (CM ') Figure 98. Infrared spectrum of 0.1 molar HDPM in CCl^, NaCl cell

Figure 99* Infrared spectrum of nearly saturated UOofNCU)? in 0.1 molar HDPM in CCl^, NaCl cell J

Figure 100. Infrared spectrum of 15 percent tri-n-octyl amine in CCl^, NaCl cell 140

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 300

0 7 8 9 WAVELENGTH (MICRONS)

FREQUENCY (CM') 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

7 8 9 WAVELENGTH (MICRONS)

FREQUENCY (CM1) 2000010000 5000 4000 3000 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800

7 8 9 WAVELENGTH (MICRONS) Figure 101. Infrared spectrum of nearly saturated UOgfNO^g in 15 percent tri-n-octyl amine in CCI4, NaCl cell 142

FREQUENCY (CM') 2000010000 5000 /000 30CO 2500 2000 1800 1600 1400 1200 1100 1000 950 900 850 800 750 100

WAVELENGTH (MICRONS)