Synthesis and structural characterization of two new hexagonal osmates: Ba_2Fe_(0.92)Os_(1.08)O_6 and Ba_2Co_(0.77)Os_(1.23)O_6

摘要

Two complex oxides of osmium, Ba_2Fe_(0.92)Os_(1.08)O_6 and Ba_2Co_(0.77)Os_(1.23)O_6, have been prepared as single crystals from molten potassium hydroxide. Both oxides crystallize in the hexagonal space group P6_3mc with a = 5.7403(1) A and c = 14.0771(6) A and a = 5.7745(2) A and c = 14.0946(7) A for Ba_2Fe_(0.92)Os_(1.08)O_6 and Ba_2Co_(0.77)Os_(1.23)O_6, respectively. The structure of these compounds is related to the 6H-BaTiO_3 structure but exhibit mixed occupancy of both metals on the three crystallographically independent metal sites.