Ewens-Bassett Number

Evolutionary technology Evolved gas analysis Ewens-Bassett numbers... 

An additional aspect of nomenclature is the procedure of identifying the charge on a complex cation or anion by a number in parentheses after the name. The numbers indicating the charges are known as Ewens-Bassett numbers. Some examples showing both procedures for specifying charges and oxidation states are as follows ... 

Evolved gas analysis (ega), 14 234 Ewens-Bassett numbers, 17 391, 392 Examiners citations, 18 237, 238 Exanta, 4 100t, 102 Excess properties, ideal mixture and,... 

Modified Forms in Common Use. There are numerous situations in which the foregoing system does not meet all requirements. In the formation uf binary compounds, several elements exhibit more Ilian two states of oxidation. One method, recommended by the IUPAC, of handling these situations is the use of prefixes derived from Greek to indicate stoichiometric composition, e.g., titanium dichloride, TiCL and dinitrogen oxide (nitrous oxide) N 0. Other accepted methods ofindicating proportions of constituents are the Stock system (oxidation number) and the Ewens-Bassett (charge number) system. 

Rule 7. Negative Stock numbers and zero were recognized. The Ewens-Bassett charge numbers were rejected. 

There exists an alternative to the Stock nomenclature called the Ewens-Bassett nomenclature (5) or the charge-number nomenclature. This is somewhat less convention loaded. For example, K PtCl has the charge number name potassium hexachloroplatinate(2-), which only involves the assumption that potassium, which behaves cationically in solution, is potassium(l+). This is not a very audacious assumption for a cnemist. 

Eadicals having special names are listed in Table 3 (p. 24). Thio-, seleno-, etc., prefixes may be used with these, as with acids. The -yl principle is noted in the i es as not extensible to other metal-oxygen radicals. In some cases use of Stock numbers or the Ewens-Bassett system extends the range of utility of these special radical names, e.g., FO + uranyl(vi) or uranyl(2 + ), UO uranyl(v) or uranyl(H-). 

Ewens and Bassett (7) have presented arguments favoring the indication of ionic charge (in Arabic numerals) instead of the oxidation state. They state that the expression zero valent elements in such compounds as Ni(CO)4 and K [Ni(CN)4] is meaningless. It is unfortunate that the terms valence and valency have been used in the sense both of oxidation state and of number of bonds. The expression element of oxidation state zero is not meaningless but indicates the most important characteristic of these compounds. 

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