Calcium hydrogen phosphate, CAS No.7757-93-9, white monoclinic crystalline powder, odorless, tasteless. It is usually present in the form of two hydrate (whose chemical formula is CaHPO4, 2H2O),
which is stable in air and heated to 75 DEG C, beginning to lose crystalline water and become anhydrous, while high temperature becomes pyrophosphate. Soluble in dilute hydrochloric acid, dilute
nitric acid and acetic acid, slightly soluble in water (100 DEG C, 0.025%), insoluble in ethanol.