Nickel Monoxide: Nickel Hydroxide Precipitated with Alkali and Strongly Heated

Nickel monoxide, NiO, is a green crystalline powder that turns yellow while hot. Thorpe's Dictionary (1912): a nickel salt treated with alkali hydroxide gives an apple-green precipitate of nickel hydroxide, and strongly heating the hydroxide leaves the monoxide. No amounts or temperature are given. Nickel compounds are a cancer hazard when breathed in: work the dry powder with a respirator. The picture: our diagram.