Calcium stearate

Calcium stearate is a carboxylate of calcium, classified as a calcium soap. It is a component of some lubricantssurfactants, as well as many foodstuffs. It is a white waxy powder

Calcium stearate is produced by heating stearic acid and calcium oxide:

2 C17H35COOH + CaO → (C17H35COO)2Ca + H2O

It is also the main component of soap scum, a white solid that forms when soap is mixed with hard water. Unlike soaps containing sodium and potassium, calcium stearate is insoluble in water and does not lather well.[2] Commercially it is sold as a 50% dispersion in water or as a spray dried powder. As a food additive it is known by the generic E number E470