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The Crystal Structure of Vauquelinite and the Relationships to Fornacite by L

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Zeitschrift fUr Kristallographie, Bd. 126, S. 433-443 (1968) The crystal structure of vauquelinite and the relationships to fornacite By L. FANFANI and P. F. ZANAZZI Istituto di Mineralogia dell'Universita di Perugia (Received October 25, 1966) Auszug Vauquelinit Pb2CuCr04P040H hat die Gitterkonstanten a = 13,754, b = 5,806, c = 9,563 A, f3 = 94034'. Raumgruppe ist P21/n. Die Struktur wurde nach der Methode "trial and error", von den im Pb2CuCr04As040H gefundenen Atomlagen ausgehend, bestimmt. Die Verfeinerung nach der Aus- gleichsmethode ergab R = 0,089. Die Atomanordnung im Vauquelinit ist sehr ahnlich der des Fornacits; geringe Unterschiede bestehen nur in der Umgebung cler Pb-Ionen und in der Anordnung der Symmetrieelemente (Fornacit hat die Raumgruppe P21/c). Abstract Vauquelinite, Pb2Cu [CrO 4PO 40H], is monoclinic, with a = 13.754, b = 5.806, c = 9.563 A, f3 = 94°34', space group P21/n. The crystal analysis of the mineral was determined by the trial-and-error method starting from the atomic positions found in fornacite. The refinement carried out by the least-squares method gave a final discrepancy index R of 0.089. The atomic packing in vauquelinite is very similar to that in fornacite. Some differences occur in coordination around lead ions and in the arrangement of symmetry elements in the two minerals. Introduction The mineral vauquelinite is a basic lead and copper chromophos- phate belonging to the monoclinic system with space group O~h-P21/n (BERRY, 1949). GUILLEMIN and PROUVOST(1951) assigned the formula Pb2Cu[Cr04P040H] to the mineral. From diffractometric data and chemical analogies between vauquelinite and fornacite, a basic lead and copper chromoarsenate, these authors suggested the two minerals belong to an isomorphous series. BARIAND and HERPIN (1962) deter- mined the unit cell of fornacite and related its lattice parameters to those of vauquelinite. The crystal analysis of fornacite was carried out (Cocco, FANFANI and ZANAZZI, 1967). In order to explain better the relations between the two minerals, the present investigation was undertaken. Z. Kristallogr. Bd. 126, 5/6 28 434 L. FANFANI and P. F. ZANAZZI Crystal data Crystals of vauquelinite from Beresov were used for the present work. The lattice parameters previously reported (BERRY, 1949) were refined by least-squares computations employing data from a powder diffractogram. The unit-cell constants are as follows: a = 13.754:::!:::.005 A b = 5.806:::!:::.006 A c = 9.563:::!:::.003 A (3 = 94°34':::!::: 2'. The space group is P21/n, Z = 4 and Dx = 6.16 g cm-3. The observed value D is 6.16 g cm-3 (GUILLEMIN and PROUVOST, 1951). The linear absorption coefficient fl is 1021 cm-1 for CuKo.: radiation. A spherical specimen with radius 0.11 mm was prepared for the intensity-data collection. X-ray diffraction effects hOl, hll, h2l, and h3l were recorded by an integrating Weissenberg apparatus on multiple films using Ni-filtered CuKo.: radiation. A total of 1067 independent reflections were observed and they were measured with the help of a micro densitometer. Empirical correction for 0.:1-0.:2doublet resolution was applied. Then Lorentz-polarization and absorption corrections were carried out. The transmission factors at different () for a value flR = 11.3 were obtained by graphical interpolation from the values of EVANs and EKSTEIN (1952). Crystal-structure determination There are evident similarities between fornacite and vauquelinite. The lattice parameters of vauquelinite are very close to those of fornacite when one chooses as a and c axes of the unit-cell the [101] and [101] directions. The values of the parameters of vauquelinite according the new orientation are here compared with those of fornacite: vauquelinite a = 16.110 A, b = 5.806 A, c = 17.366 A, (3 = 110°28' fornacite a = 8.101 A, b = 5.893 A, c = 17.547 A, (3= 110°00'. The two minerals show the same prominent pseudocell, corresponding to the cell of fornacite with c halved. Furthermore, assuming the same orientation for the two cells, the intensities of correspondent spots are similar. Figure 1 shows a part of the h3llayer of the weighted reciprocal lattice for vauquelinite and fornacite. From these considerations it follows that the two structures are closely related. Therefore we were led to propose a trial arrangement The crystal structure of vanquelinite 435 for the heavy atoms in vauquelinite derived from the arrangement found in fornacite. The agreement between calculated and observed structure factors was satisfactory. A first refinement of the locations of these atoms was carried out with a Fourier synthesis. Then it was possible to locate oxygen atoms from difference-Fourier syntheses and stereochemical considerations. c* c* . ,. ' .. .' . ,. '. ' .' '.' . -- . a) a* b) Fig. 1. A part of the h3llayer of the reciprocal lattice of (a) vanqnelinite, and and (b) fornacite. The size of spots is set approximately proportional to the Fo2 The refinement of the structure was performed with the least- squares method. The weighing scheme suggested by CRUICKSHANK et al. (1961) was employed and the unobserved reflections were not included in the calculations, After four cycles of isotropic refinement, each followed by a proper resealing of lFol's, the discrepancy index R = L'llFol- IFcll/L'lFol for 523 observed reflections fell to the final Table 1. Fractional atomic coordinates with standard deviations and isotropic temperature factors Atom x y z B Pb(1) .7363 :t .0002 .2256 :t .0013 .4954 :t .0002 2.99A2 Pb(2) .0535 1 .7686 12 .1666 2 2.22 Cu(1) .0000 - .0000 - .5000 - 2.96 Cu(2) .0000 - .5000 - .5000 - 1.33 Cr .8620 6 .2625 47 .1811 8 1.69 P .1584 9 .2737 59 .3207 13 1.83 0(1) .1203 37 .0478 128 .3806 53 3.13 0(2) .1104 37 .4780 117 .3868 54 3.25 0(3) .1192 29 .2589 179 .1679 43 2.53 0(4) .2683 31 .2951 136 .3470 45 2.50 0(5) .8910 36 .0281 124 .1013 53 2.53 0(6) .9103 36 .4836 124 .0964 54 1.98 0(7) .9113 28 .2360 192 .3381 40 1.91 0(8) .7470 30 .2735 145 .1838 44 2.32 OH .9529 28 .7837 181 .3841 42 2.21 28* 436 L. FANFANI and P. F. ZANAZZI Table 2. Observed and calculated structure factors ) h k F F, h k F F, h k , ,, h k 1 r, 0 0 0 '0 ,2 0 0 7.2 8 0 - 6 17.2 8 1 1 12.6 6 1 It 221.6 -215.4- 0 0 190,4 215.0 1-00 6 153.0 -150.6 9 1 - 1 214.0 --190.6 7 1 - , 22.8 6 0 0 250,2 -256.6 10 0 6 183.8 _200.4 9 1 1 73.1 71.8 7 1 , 4.6 8 0 0 135.6 114.0 12 0 - 25.4 10 1 - 1 15.2 8 1 - , 258.8 100 0 - 2"".6 254.2 -237.6 12 0 - 6 45.9 47.4 10 1 - 1 11.6 8 1 122.8 -116.6 12 0 0 8.8 1 0 7" H.D 11 1 1 57.1t 67.6 - , ,., - 9 1 ,"- _ J.' 0 0 1 o - 7 27." 11 1 1 122.5 105.2 9 1 26.0 16 0 0 78.1 69.8 3 0 7 155.2 -16IJ.o 121 - 1 5.0 10 1 - , 17.6 "1 o 1 90.5 117.8 100.0 _ 21t.S , - 3 0 - 7 105.3 _ 12 1 - 1 101 - , 186.5 -167.2 3 0 1 252.9 -272.4 5 0 7 8}.8 86.2 131 1 155.9 -111}.8 11 1 , 12,0 3 0 - 1 51.4 5 0 7 1lI3.6 135.0 131 1 68.5 54.6 11 1 29.8 5 0 1 182.9 -186.2 7 0 - 7 229.7 -21t1.2 - 1 - 13.8 121 - , 154.5 138,0 5 0 1 159.2 169.0 7 0 7 19.6 "1 1 ,., 12 1 4. 111.0 - 396,1) - - "1 - - - , 93.2 70 1 -)Y5.0 9 0 7 2.0 151 1 - 8.' 131 , - 19.0\ 7 0 1 103.0 - 91.8 9 0 - 7 51. 7 45.2 15 1 1 28.9 29.2 131 3.6 9 0 - 1 2.0 110 7 74.0 - 73.0 16 1 - 1 - 1- , 30.6 H.6 1 - o - 7.' , - 9 0 - - 2.' 11 - 7 169.5 -177.2 161 - 1 5.' ""1 - , .H.t - 37.8 11 0 1 157.4 -143.6 13 0 7 61t.2 57.8 17 1 1 52.5 _ 39.8 151 - 7.0 11 o - 1 289.0 -273.2 13 0 - 7 - 25.1t 17 1 1 97.8 88.6 15 1 It 8.8 130 1 11t2.3 108.8 o 0 8 It1. 6 o 1 - 2 171.9 208.4 161 - , 50.1t 50.8 13 0 1 35.8 2 0 8 168.6 11 2 45.1t 16 1 It 88.0 - - -172.0 - - 80.8 150 1 2 0 8 19.1t 11 -2 9.6 o 1 5 12.6 15 0 1 9." , - - - - 150.3 -lito. It 0 8 16.0 2 1 2 5.6 1 1 5 205.6 -211.6 17 0 1 108.2 It 0 8 305.1 291.8 21 2 236.6 -288.2- 1 1 5 16.2 1 30.8 6 0 - 8 ll1t.6 - - 17 0 - '.0 -121'.1t 31 2 - 31.8 2 1 5 54.\ o 0 2 107.0 113.0 6 0 8 19.6 3 1 2 16.6 2 1 5 35.2 2 0 2 21t1.3 80 - 8 , - - 86., _2"2.8 _ 75.8 89.2 1 2 33.6 3 1 5 85.9 2 0 2 183.8 8 0 8 lIt7.2 It 1 2 121t.9 , - -219.2 137.6 - -13".0 ,3 1 - 5 375.4 390.1& , 0 2 71.8 73.8 100 8 56.6 69.2 51 2 - 55.6 , 1 5 o 2 536.1 585.1t 10 0 8 26.1t 5 1 2 29.6 1 29.2 - - - _262.0 - 5 - '-' 6 0 2 366.2 -353.8 12 0 8 62.0 71t.o 6 1 2 263.7 _ 51 5 117.9 -110,8 6 0 2 192.7 187.0 12 0 8 27.7 39.2 6 1 2 90.5 86.8 51 5 113.1 -107.0 80 - 2 201.1 186.2 lit 0 - - - - 8 70.5 - 78.1t 7 1 2 15.8 6 1 5 ".0 8 0 2 278.3 287.0 1 0 9 129.8 -131.
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  • Rongibbsite, Pb2(Si4al)O11(OH), a New Zeolitic Aluminosilicate Mineral with an Interrupted Framework from Maricopa County, Arizona, U.S.A

    Rongibbsite, Pb2(Si4al)O11(OH), a New Zeolitic Aluminosilicate Mineral with an Interrupted Framework from Maricopa County, Arizona, U.S.A

    American Mineralogist, Volume 98, pages 236–241, 2013 Rongibbsite, Pb2(Si4Al)O11(OH), a new zeolitic aluminosilicate mineral with an interrupted framework from Maricopa County, Arizona, U.S.A. HEXIONG YANG,* ROBERT T. DOWNS, STANLEY H. EVANS, ROBERT A. JENKINS, AND ELIAS M. BLOCH Department of Geosciences, University of Arizona, 1040 East 4th Street, Tucson, Arizona 85721-0077, U.S.A. ABSTRACT A new zeolitic aluminosilicate mineral species, rongibbsite, ideally Pb2(Si4Al)O11(OH), has been found in a quartz vein in the Proterozoic gneiss of the Big Horn Mountains, Maricopa County, Arizona, U.S.A. The mineral is of secondary origin and is associated with wickenburgite, fornacite, mimetite, murdochite, and creaseyite. Rongibbsite crystals are bladed (elongated along the c axis, up to 0.70 × 0.20 × 0.05 mm), often in tufts. Dominant forms are {100}, {010}, {001}, and {101}. Twinning is common across (100). The mineral is colorless, transparent with white streak and vitreous luster. It is brittle and has a Mohs hardness of ∼5; cleavage is perfect on {100} and no parting was observed. 3 The calculated density is 4.43 g/cm . Optically, rongibbsite is biaxial (+), with nα = 1.690, nβ = 1.694, Z nγ = 1.700, c = 26°, 2Vmeas = 65(2)°. It is insoluble in water, acetone, or hydrochloric acid. Electron microprobe analysis yielded an empirical formula Pb2.05(Si3.89Al1.11)O11(OH). Rongibbsite is monoclinic, with space group I2/m and unit-cell parameters a = 7.8356(6), b = 13.913(1), c = 10.278(1) Å, β = 92.925(4)°, and V = 1119.0(2) Å3.
  • Zinc-Rich Zincolibethenite from Broken Hill, New South Wales

    Zinc-Rich Zincolibethenite from Broken Hill, New South Wales

    Zinc-rich zincolibethenite from Broken Hill, New South Wales Peter A. Williams', Peter Leverettl, William D. Birch: David E. Hibbs3, Uwe Kolitsch4 and Tamara Mihajlovic4 'School of Natural Sciences, University of Western Sydney, Locked Bag 1797, Penrith South DC NSW 1797 ZDepartmentof Geosciences, Museum Victoria, PO Box 666, Melbourne, VIC 3001 3School of Pharmacy, University of Sydney, Sydney, NSW 2006 41nstitutfiir Mineralogie und Kristallographie, Geozentrum, Universitat Wien, Althanstrasse 14, A-1090 Wien, Austria ABSTRACT Zinc-rich zincolibethenite with the empiricalformula (Zn,,,,,Cu,,) ,, l(P,,~s,,,,) ,, 0,IOHisimplifed formula (Zn,Cu),PO,OH), occurs inferruginousgossunfrom theNo 3 lens, 280RL lmel, Block 14 open cut, Broken Hill, New South Wales, Australia, associated with corkite-hinsdalite, tsumebite, pyromorphite, sampleite, torbernite, dufienite, strengite and beraunite. Zinc-rich libethenite and olivenite are also associated with the zone, together with members of the libethenite-olivenite series. It is possible that solid solution in thephosphateseriesextends to theorthorhombicpolymorphofcompositionZn,P040H.Thecrystalstructureofa B~okenHillsample has been refined to Rl(F) = 0.0227 (single-crystal X-ray intensity data; a = 8.323(1), b = 8.251(1), c = 5.861(1)A, V = 402.5(1)A3; structuralformula Zn(Cu,,,,Zn,,,)i(P,,,~s0,02~OPIOH~.Detailedphysical andchemical dataarepresented, someofwhich supplement the partially incomplete data for type zincolibethenitefiom Zambia. INTRODUCTION An extremely diverse suite of secondary arsenates and Pnnm, witha = 8.3263(3), b = 8.2601(3), c = 5.8771(2) P\, V = phosphates occurstowards thebase of the oxidised zone of 402.52(10)A3 (Z = 4). Synthetic studies by Braithwaiteet al. the Broken Hill ore body (Figure 1). Minerals, including (2005)showed that, in boilingaqueons solution, no excessZn this suite, from the Block 14 and Kintore open cuts have was accommodated by the lattice, despite the fact that the been described in detail by Birch and van der Heyden Pnnm polymorph of Zn2P040His known as a synthetic, (1997).