A new family of compounds with tetrahedral anions: Pb_nBiO_n(XO_4), X = V, P, As, n = 1, 2, 4.

摘要

The thermal behavior and crystallographic characteristics of nine compounds, Pb_nMO_n (XO_4) with M = Bi, Pb, X = V, P, As, S and n = 1, 2,4, are reported. A previously reported #gamma# phase for Pb_2BiO_2(VO_4) was shown to consist of a mixture of PbBiO(VO_4) and Pb_4BiO_4(VO_4) that resulted from a kinetically controlled decomposition of Pb_2BiO_2(VO_4) at elevated temperatures. The relationship between the #alpha#, #beta# and #delta# transitions for Pb_2BiO_2(VO_4) was clarified. All of these phases contain the tetrahedral anion XO_4 that imparts thermal and structural similarities as well as specifications that can be ascribed to anion size differences.