Phase chemistry in the Ca-Mn-Sb-O system at 1160-1250 °C

Abstract

Phase equilibrium in the Ca-Mn-Sb-O system was studied in air at the temperature range from 1160 to 1250°C and a pseudo-quaternary phase diagram for the system CaO-MnO-Mn2O3-Sb2O5 is presented. The following compounds were discovered: new antimonate Ca 7Sb2O12 with a perovskite-like structure, solid solutions Mn2-xCaxSb2O7 (0 ≤ x ≤ 1.6) with a 3T-weberite structure, and Ca2-xMn xSb2O7 (0 ≤ x ≤ 0.23) with a 2O-weberite structure, as well as solid solutions Ca2Mn1+xSb 1-xO6 with monoclinic (0 ≤ x ≤ 0.67) and orthorhombic (0.75 ≤ x ≤ 1) perovskite structures. The existence of a number of double and ternary oxides and solid solutions on the basis of Sb 5+ and Mn2+, Mn3+, Mn4+ and with mixed manganese valence is confirmed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.