Cuprous hydride, CuH

Addition of a concentrated solution of cupric sulphate to a solution of hypophosphorous acid or of zinc hypophosphite yields a powder containing 1.22 per cent, of hydrogen, but the chemical individuality of the product is open to question. Berthelot doubted the possibility of the existence of cuprous hydride, CuH, but more recent work has proved his views to be erroneous. The pure hydride can be prepared by the action of sodium hypophosphite on a moderately dilute solution of cupric sulphate at 70° C., but the product formed at ordinary temperature is contaminated with cuprous oxide and cupric phosphate. It is a very unstable, reddish-brown substance, takes fire in chlorine, and is converted by hydrogen chloride into hydrogen, copper, and cuprous chloride. The dry substance cannot be kept for more than twenty-four hours, and at 60° C. decomposes suddenly, leaving a sponge of metallic copper.

A very unstable copper hydride of unknown composition has been prepared in the form of a dark-brown powder by Stock and Kuss by the interaction of cupric sulphate and potassium hypoborate, KH₃OB. It decomposes readily, evolving hydrogen, and leaving a brown residue of metallic copper.