Calculation of enthalpies of formation of compounds of the type M/sub 5/R(EO/sub 4/)/sub 4/

Enthalpies of formation were determined for compounds of the M/sub 5/R(EO/sub 4/)/sub 4/ type, where M = Li, Na, K, Rb, Cs, Fr, Tl, Ag, Cu; R = the rare earth elements, y, Bi; and E = Mo, W. Values of ..delta..Hf/sup 0/, either experimentally determined or estimated by any quantum-chemical methods, are absent in the literature for these compounds. The obtained values of lambdaHf/sup 0/ for M/sub 5/R(EO/sub 4/)/sub 4/ are presented.