Cobalt Monosilicide, CoSi

Cobalt Monosilicide, CoSi, is formed as prismatic needles by heating cobalt and copper silicide in the electric furnace. It melts at 1300° C. in hydrogen, and has a density of 6.30 at 20° C. When heated in fluorine it incandesces, yielding fluorides. Chlorine decomposes it only at a dull red heat, but it dissolves slowly in aqua regia and more rapidly in concentrated hydrogen chloride. It melts at 1393° C.