Calcium nitrate

Calcium nitrate, also called Norgessalpeter (Norwegian saltpeter) and Kalksalpeter, is a white coloured soluble hygroscopic salt absorbs moisture from the air with the formula Ca(NO3)2. It is commonly found as a monohydrate, with the formula Ca(NO3)2.H2O and a molecular weight of 182.11 g/mol. It is used as a reagent, a pyrotechnic and a fertilizer. The fertilizer grade (15.5-0-0 + 19% Ca) is popular in the greenhouse and hydroponics trades; it has some ammonium nitrate and water incorporated in the molecular structure as 5Ca(NO3)2.NH4NO3.10H2O. There also is a formulation without ammonia: Ca(NO3)2.3H2O (12.8-0-0 + 18.3%Ca).

Norgessalpeter was the first nitrogen fertilizer compound to be manufactured. Production began at Notodden, Norway in 1905. Most of the world's calcium nitrate is now made in Porsgrunn.

Nitrocalcite is a form of calcium nitrate which occurs in nature. It occasionally forms an efflorescence where manure contacts concrete or limestone in a dry environment, as in stables or caverns.