Chemical Engineering - Chemical Engineering Basics - Discussion

Nickel is silvery-white. Hard, malleable, and ductile metal. It is of the iron group and it takes on a high polish. It is a fairly good conductor of heat and electricity. In its familiar compounds nickel is bivalent, although it assumes other valences. It also forms a number of complex compounds. Most nickel compounds are blue or green. Nickel dissolves slowly in dilute acids but, like iron, becomes passive when treated with nitric acid. Finely divided nickel adsorbs hydrogen.

Chromium metal lacks ductility and is susceptible to nitrogen embrittlement, and is not used as a structural metal.