Calcium phosphide Calcium phosphide Calcium phosphide (CP) is the inorganic compound with the formula CaP. It is one of several phosphides of calcium, being described as the salt-like material composed of Ca and P. Other, more exotic calcium phosphides have the formula CaP, CaP, CaP, and CaP. CaP has the appearance of red-brown crystalline powder or grey lumps. Its trade name is Photophor for the incendiary use or Polytanol for the use as rodenticide. It may be formed by reaction of the elements, but it is more commonly prepared by carbothermal reduction of calcium phosphate: The structure of the room temperature form
Calcium citrate sulfuric acid. In many individuals, bioavailability of calcium citrate is found to be equal to that of the cheaper calcium carbonate. However, alterations to the digestive tract may change how calcium is digested and absorbed. Unlike calcium carbonate, which is basic and neutralizes stomach acid, calcium citrate has no effect on stomach acid. Calcium carbonate is harder to digest than calcium citrate, and calcium carbonate carries a risk of "acid rebound" (the stomach overcompensates by producing more acid), so individuals who are sensitive to antacids or who have difficulty producing adequate stomach acid may choose calcium citrate over calcium carbonate