Ammonium nickel sulphate hexahydrate is a pale green, crystalline double salt containing nickel(II) in a stable, well-defined hexahydrate form. Its predictable composition and solubility make it useful in analytical chemistry, electrochemistry, and as a controlled nickel source for various synthesis routes.

It is widely employed as a reagent in nickel determination methods, in electroplating baths, and in the preparation of nickel-containing catalysts and coordination compounds. The material is also used in certain dyeing and finishing processes where nickel complexes play a functional role.

The selection of grade should be based on impurity limits and the nickel(II) sensitivity of the end application, especially for analytical or high-purity chemical work.