University of South Florida Scholar Commons Chemistry Faculty Publications Chemistry 2014 Nonexistent Compounds as a Guide to Innovation Dean F. Martin University of South Florida, [email protected] Barbara B. Martin University of South Florida, [email protected] Follow this and additional works at: http://scholarcommons.usf.edu/chm_facpub Part of the Chemistry Commons Scholar Commons Citation Martin, Dean F. and Martin, Barbara B., "Nonexistent Compounds as a Guide to Innovation" (2014). Chemistry Faculty Publications. Paper 4. http://scholarcommons.usf.edu/chm_facpub/4 This Article is brought to you for free and open access by the Chemistry at Scholar Commons. It has been accepted for inclusion in Chemistry Faculty Publications by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Technology and Innovation, Vol. 16, pp. 271–276, 2014 1949-8241/14 $90.00 + .00 Printed in the USA. All rights reserved. DOI: http://dx.doi.org/10.3727/194982414X14138187301812 Copyright Ó 2014 Cognizant Comm. Corp. E-ISSN 1949-825X www.cognizantcommunication.com NONEXISTENT COMPOUNDS AS A GUIDE to INNOVation Dean F. Martin and Barbara B. Martin Institute for Environmental Studies, Department of Chemistry, University of South Florida, Tampa, FL, USA A study of nonexistent compounds can be a useful exercise in gaining insight into the factors that can inhibit innovation. Several reasons are suggested: lack of financial support, disinterest in preparing compounds that lack evident utility, notable synthetic challenges with inadequate rewards, inhibition by well-established contemporary knowledge, and invalid interpolations. Key words: Argon; Autohypnosis; Innovation; Isomers; Noble gases; Xenon INTRODUCTION timely to consider some current reasons for certain nonexistent substances. A fascinating review article, written by E. H. Appelman (4), explored the reasons certain com- pounds were unknown: His view was that they fit LACK OF NEED, LACK OF into three categories: FINANCIAL SUPPORT Dr. Alfred Werner, a chemistry faculty member • Extensions of existing knowledge that no one has in Zurich in the last decade of the 19th century and bothered to prepare; for about 15 years of the 20th, became known as • Extensions of knowledge, but attempts to prepare “The Father of Coordination Chemistry.” In an era them were unsuccessful; when conductivity was the major physical method • Whole areas of chemistry that “have not been of characterization of compounds, he was forced to studied or have been written off as unfruitful for use an isomer number pattern as a means of structure synthetic work” (4). evaluation. For example, for the compound called dichlorodiammineplatinum(II), [PtCl2(NH3)2], two One may properly note that there is really no short- structures—tetrahedron or square plane—could be age of compounds. The Chemical Abstracts Service predicted. If the structure was a regular tetrahe- RegistryTM of the American Chemical Society con- dron, Werner predicted the compound could exist tains more than 72 million unique organic and inor- as a single entity. If the structure was square planar, ganic substances (2). The list is updated daily with there could be two geometric isomers termed cis about 15,000 substances (2). and trans (18). The correct structure was predicted The reasons for concern about the absence of (18). The two geometric isomers were known, and certain substances are, however, because they are the structure corresponded to the prediction. related to inhibition of innovation. A certain unpre- A more complicated example of an isomer number pared substance, if found, might well have proper- set of compounds can be represented as Mabcdef, ties of value for technology. Accordingly, it seems where M is a transition metal ion, most likely Pt(IV), Accepted June 17, 2014. Address correspondence to Dean F. Martin, Distinguished University Professor of Chemistry Emeritus, Department of Chemistry, CHE 205, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620, USA. Tel: +1-813-974-2374; Fax: +1-813-974-3203; E-mail: [email protected] 271 272 MARTIN AND martin and the other letters denoted different unidentate Examples of failed efforts were presented by ligands (single bond to the metal ion), for example, Moeller (19). Cl-, Br-, I-, H2O, NH3, that would be arrayed in the form of an octahedron around the central metal ion. CONFLICT WITH SUCCESS AS Bailar noted that there could be no more than 30 A PROBLEM isomers, that is, 15 pairs of optical enantiomers. He worked out a means of representing these isomers The noble gases represented a problem from that was and remains fascinating (5). the outset. Lord Rayleigh and Sir William Ramsay The major point of interest is the obvious synthetic had the misfortune to discover argon first. It was challenge, as well as what seems as an equally obvi- announced in an address in January 1895 that the new ous lack of need. One can hardly imagine an admin- gas had a molecular weight of about 40 g/mol, and istrator at the National Science Foundation seeing a because the Mendeleev periodic table was arranged need for any of the 30 compounds. Nor could one by increasing atomic mass (the atomic number imagine an independently wealthy chemist feeling concept would not be established until H. G. J. the need to undertake the incredible challenge of the Mosely’s report in 1913), the ratio of specific heats synthesis. This is surely understandable, but there is (Cp/Cv) was found to be 1.66, which was consistent always a thought: Could not a single isomer be of with a monoatomic gas (unfortunately, the theory some significant value? It is unlikely that we shall had only been tested for one monoatomic gas, mer- ever know, considering over a century of avoidance cury vapor). Given the atomic weight (at.wt.) of of this synthetic challenge. 40 g/mol, the element should logically be between Related to that concern is the question of prestige. potassium (at.wt. = 39.09 g/mol) and calcium (at.wt. = How likely would the work be cited? What major 40.08 g/mol) or perhaps between calcium and scan- journal with a high impact factor (the number of dium (at. wt. = 44.95 g/mol). times in a given year that articles in the journal are The pair had discovered one of three examples cited in other journals) would be likely to accept a of inversions of atomic weight. One pair, cobalt paper describing the synthesis? The concern over (at.wt. = 58.93) and nickel (at. wt. = 58.69), had not journal impact factors has been criticized by Alberts troubled Mendeleev, who placed them correctly (1), and while his criticism is well taken, the con- in his table (possibly he presumed that the known cern remains. atomic weights were incorrect). Ramsay had been able to isolate argon first because argon is the most abundant of the noble gases in the atmo- “AUTOHYPNOSIS” sphere (9,340 ppm vs. 0.086 ± 0.001 ppm for Xe). Appelman (4) noted that certain compounds The authors would have had trouble placing neon have “resisted discovery for long periods of time. (18.18 ± 0.04 ppm) in an 1870s periodic table because Only to be synthesized quite painlessly once the of the monoatomic nature, seemingly inert behav- initial breakthrough has been made.” He asked an ior, and the absence of a “column” for these gases internationally renowned chemist–academician V. I. in Mendeleev’s table. Spitzyn why this should be true, and the answer was The rigidity of thought also was backed by “Autohypnosis” (4). Mendeleev’s prediction of certain elements “miss- Based on experience, ours or others’, we become ing” from his periodic table, as well as the fact that convinced that certain compounds will not exist. The when these “missing” elements were discovered, prime example is the so-called inert gases, Group 18 their properties were in good agreement with pre- in a contemporary periodic table, later renamed the dicted values (Table 1). The table is significantly noble gases. No examples of compounds of these condensed, and, in fact, the predictions included the elements had been observed, despite some signifi- formula of the oxide with some predicted proper- cant efforts. Therefore, it was a generally accepted ties, nature of the salts, formula of the anhydrous conclusion that they were properly named inert salts, how it would be discovered (spectroscopically gases because of a lack of credible evidence (vide or not). The predictions were made in 1871, and infra) of the formation of any chemical compounds. gallium was discovered by Lecoq de Boisbaudran, a NONEXISTENT COMPOUNDS 273 Table 1. Some Properties Predicted by Mendeleev (1871) in Comparison With Those Later Discovered (23) Element Abbr. Element Date Atomic Weight Specific Gravity Predicted Observed Ea* Galium 1875 ~68 69.7 5.9 5.94 Eb Scandium 1879 44 44 3.5† 3.86† Es Germanium 1886 72 72.3 5.5 5.47 *E, eka, a sanskrit word for one. Mendeleev meant to refer to unknown. The element one above a known one in a given column Ea was eka aluminum; for Eb was eka boron; and for Es was eka silicon. †Specific gravity for the oxide. Frenchman, who patriotically named it gallium (23). Subsequently, Bartlett noted that the first ion- Certainly one could see why Ramsay would have had ization potential for oxygen was similar to that of a problem convincing scientists that he had discov- xenon (Table 2), for example, 12.2 eV and 12.13 eV, ered new elements given the success of Mendeleev respectively. He noted that it appeared that xenon in making his “eka predictions” (cf. Table 1). But might be oxidized by the hexafluoride (7). The other problems can now be recognized, including resulting product was an orange-yellow solid, insol- atmospheric concentration of the noble gases as uble in carbon tetrachloride, and underwent hydro- an example.