Ewens-Bassett system

This is the Ewens-Bassett system of indicating charge on the complex (and indirectly, the oxidation state of the metal) Ewens. R. V. G. Bussett, K. Chem. Ir d. (949,27, 131.]... 

Rule 7. The Ewens-Bassett system of designating the charge on a coordination ion is accepted as an alternate to the Stock system for indicating the oxidation state of the central atom. 

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-). 

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. 

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