Cobaltous oxide with the zinc blende/wurtzite-type crystal structure

Abstract

COBALTOUS oxide, CoO, prepared by strong ignition of cobalt compounds, has the sodium chloride type crystal structure with a0 Combining double low line 4.24 Å., giving a Co-O distance of 2.12 Å. consistent with ionic radii of 0.82 Å. for Co2+ and 1.32 Å. for O2-. Its existence with a structure essentially that of the zinc blende/wurtzite type has, however, now been discovered during an investigation1 of the thermal decomposition of anhydrous nickel and cobalt acetates, butyrates and caprylates. The new phase occurs as a dark green residue when these salts are decomposed in vacuo or in a nitrogen stream, in the temperature-range 280-320°C.: other products present include small amounts of cobalt metal, carbon and CoO (sodium chloride type), the acetate giving the best yield of the new phase and with only approximately 4 per cent free cobalt metal and approximately 4 per cent carbon. © 1962 Nature Publishing Group.