Phosphate

(fas' -fat). A salt of phosphoric acid. As phosphoric acid has three replaceable hydrogen atoms, we have three kinds of salts: P., Normal, in which the three hydrogen atoms, or the six of two molecules, are substituted by metals,, Ca,r P., Dibasic, or P., Monohydric, in which two hydrogen atoms are replaced bya base, as P., Monobasic, or P., Dihydric, in which only one hydrogen atom of.the acid molecule is replaced by a metal or radicle, e. g., P., Acid, a dihydric or monohydric phosphate. P., Acid Sodium, the salt to which the acidity of urine is chiefly due. P., Alkaline, a normal or acid phosphate of the alkaline metals. P., Ammonio-magnesium, a double salt of ammonium and magnesium combined with phosphoric acid. P., Bone, Caj„ the normal calcium ortho-phosphate found in bone. P., Disodic, the phosphate of the blood. P., Earthy, a phosphate, normal or acid, of one of the alkaline earths, calcium or magnesium. Earthy phosphates, as well as the alkaline, occur in the urine, the ratio being about one part of the former to two of the latter. For test, see Tests, Table of. P., Triple, ammonio-magnesium phosphate, occurring in the urine, often in the form of crystals, generally in the shape of a coffin, hip-roof, or envelop. See urinary Sediments, Table of.