A copper-nickel alloy is extensively used in making desalination plants for converting sea water into fresh water. Nickel steel is used for armour plate. Nickel plate protects softer metals. Finely-divided nickel is used as a catalyst for hydrogenating vegetable oils, and nickel imparts a green colour to glass. The biological role of nickel is uncertain, but both the metal and nickel sulphide are considered to be carcinogenic.
Nickel carbonyl is very toxic.
General Information Nickel is very resistant to corrosion. It is soluble in all acids except concentrated nitric acid, and is not affected by alkalis. It is a fair conductor of heat and electricity.