Prop., &c. The metal belongs to the group which includes BARIUM, STRONTIUM, and MAGNESIUM; it is of a light yellow colour; is rather harder than lead, and very malleable. It melts at a red heat. It tarnishes in a day or two, even in dry air, and in contact with moist air it breaks up like ordinary lime. Its sp. gr. is 1·55.
Tests. Salts of calcium in solution produce a white precipitate with carbonate of ammonium; it becomes far less voluminous on heating the solution, and dissolves very readily in hydrochloric acid. Sulphuric acid, when added to concentrated solutions, gives an immediate white precipitate; if the solution is not concentrated, the precipitate may separate gradually, in minute crystals; and if it is very dilute, no precipitation will take place, because sulphate of lime is soluble in about 500 times its weight of water. With neutral solutions, even when very dilute, oxalate of ammonium gives a copious white precipitate, soluble in most dilute acids.
Calcium, Acetate of. Add prepared chalk to acetic (or purified pyroligneous) acid till fully saturated; filter and evaporate, that crystals may form. Diuretic. Dose, 10 to 20 grains.
Calcium, Acid Phosphate of. Syn. Superphosphate of lime, Soluble Acid Phosphate. CaH4,2PO4. This may be procured by treating bone-earth with two thirds of its weight of oil of vitriol, as in the preliminary stage of the extraction of phosphorus. It is extensively used as a manure for turnips.
Calcium, Bibasic Phosphate. Ca2H2P2O8 + 3H2O. Dissolve 608 grams of crystallised calcium chloride in 1000 grams of distilled water, and add gradually to this solution 1000 grams of sodium phosphate, dissolved in 10,000 grams of water. Allow the precipitate to deposit, and wash it five or six times with 10 litres of water each time; drain the precipitate on a moistened cloth. As soon as its consistence permits, detach from it irregular pieces, and place them to dry in the open air upon filtering paper; the spontaneous desiccation is sufficiently rapid.
From ‘Formulæ for New Medicaments adopted by the Paris Pharmaceutical Society.’
Calcium, Bro′mide of. CaBr2. Syn. Cal′cii bromi′dum, L. Prep. (Magendie.) To a solution of bromide of iron add hydrate of calcium in slight excess; filter, evaporate to dryness, redissolve in water, and again filter, and evaporate.
Calcium, Carbonate of. See Chalk.
Calcium, Chlo′′ride of. CaCl2. Syn. Cal′cii chlori′dum (B. P.). Prep. Hydrochloric acid and water, of each 10 fl. oz.; chalk, 5 oz.; evaporate the solution until the salt becomes solid, and dry the residue at about 400° F.
It is obtained in solution as a residuum in making several preparations of ammonia, as the liquor and carbonate, and in making carbonic acid by the action of hydrochloric acid on marble. The residuum is concentrated and set aside to crystallise, or evaporated to dryness.