Correlations of heats of formation of the different valency states of solid, polyvalent binary metal compounds

Abstract

For those metal polyvalent binary compounds of the formula MX/sub z/ (where X is either metal or nonmetal), which have three or more well-defined stoichiometric valence states, there appear to be empirical relations between their heats of formation and the value of z. For 27 metals in 71 different series examined, the standard heats of formation can be correlated quantitatively by the two-parameter equation -..delta..H/sub f//sup 0//sub 298/(MX/sub z/) = a'z - b'z/sup 2/ and with smaller deviations by the equation log (-..delta..H/sub f//sup 0//sub 298/(MX/sub z/)/z) = a - bz, where a, b and a', b' are in general different pairs of constants for each compound type.