Homopolyatomic anions

The lack of homopolyatomic anions for elements to the left of group IV In Table I is noteworthy. Zlntl reported no success with reactions of alkali metal alloys of the copper and zinc family elements and of thallium with liquid ammonia, and the generally stabilizing effect of crypt has not been evident In our own Investigations of alloys of mercury and thallium. On the other hand. It is possible to Isolate a white crypt-potassium gold compound from ammonia solutions at low temperatures which decomposes to elemental gold (+ ) above about -10°C (30). 

The apparent Instability of homopolyatomic anions of elements to the left of group IV (and of polyatomic cations to the left of group V) Is thought to result from a deficiency of bonding electrons In species where the principal bonding Is considered to originate largely from p-type orbitals. The electron deficient polyboranes, with which these clusters have... 

The names of anions similarly are obtained by an extension of the names used for electronegative constituents, but with the proviso that the ending is always characteristic of an anion (ide, -ate or -ite, as discussed above). For the names of monoatomic anions, see Table 4.1. Homopolyatomic anions take names of the kind exemplified below. 

Critchlow SC, Corbett JD (1981) Stable homopolyatomic anions - the Tetrastaimide(2-) And Tetragermanide(2-) anions, Srq - And Ge4 — X-ray crystal-structure of K+(Crypt)2Sii4. Ethylenediamine. J Chem Soc Chem Commun 5 236-237... 

Corbett JD, Edwards PA (1975) Stable homopolyatomic anions - crystal-structures of salts of anions Pentaplumbide(2-) and Enneastannide(4-). J Chem Soc Chem Commun 984—985... 

Monoatomic [and homopolyatomic) anions are named by replacing the termination of the element name by ide (and adding a numerical prefix as needed). In many cases, contractions or variations are employed, as exemplified below. 

IR-5.2 Stoichiometric names of elements and binary compounds IR-5.3 Names of ions and radicals IR-5.3.1 General IR-5.3.2 Cations IR-5.3.2.1 General IR-5.3.2.2 Monoatomic cations IR-5.3.2.3 Homopolyatomic cations IR-5.3.2.4 Heteropolyatomic cations IR-5.3.3 Anions IR-5.3.3.1 Overview IR-5.3.3.2 Monoatomic anions IR-5.3.3.3 Homopolyatomic anions IR-5.3.3.4 Heteropolyatomic anions IR-5.4 Generalized stoichiometric names... 

Homopolyatomic anions are named by adding the charge number to the stoichiometric name of the corresponding neutral species, i.e. the element name with the appropriate multiplicative prefix. Again, a radical dot may be added as appropriate. 

In some cases, homopolyatomic anions may be considered as derived from a parent hydride by removal of hydrons (see Section IR-6.4). ... 

Many compounds are reduced to the free elements, to intermetallic compounds or to homopolyatomic anionic complexes containing the reduced elements. For example with lead iodide the compound Na4[Pb(Pb)8] has been obtained. 

Adolphson, D. G., J. D. Corbett, and D. J. Merryman. Stable homopolyatomic anions of the post-transition metals. Zintl ions . The synthesis and structure of a salt containing the heptantimonide(3-) anion. J. Am. Chem. Soc. 98 (1976) 7234. 

Edwards, P A., and J. D. Corbett. Stable homopolyatomic anions - Synthesis and crystal structures of salts containing pentaplumbide (2-) and pentastannide(2-) anions. Inorg. Chem. 16 (1977) 903. 

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