Prop., Uses, &c. Forms a bulky white powder, containing 101⁄2% of water of hydration, which it retains even after ignition. In this state it is soluble in 20 parts of cold water, and in 2 parts of boiling water. The hot saturated solution, as it cools, deposits abundantly columnar crystals (CRYS′TALLISED HYDRATE OF B.), which contain 511⁄2% of water, of which they lose, by drying and ignition, 883⁄4% (= 43⁄4% of their weight), being reduced to the state of the common or amorphous hydrate. Of all the bases it has the strongest affinity for both sulphuric and carbonic acid, and hence its solution (BARY′TA-WATER) and those of its neutral salts (nitrate or chloride) form our most sensitive tests for these substances. Sp. gr. 4·3 to 4·7. The crystallised hydrate is converted into the ordinary hydrate at a gentle heat, and this last fuses at a low red heat without losing its water of hydration, which it only slowly and with difficulty begins to part with at higher temperatures. In chemistry, its uses are, for the most part, similar to those of Barium, Oxide of.
Barium, Iodide of. Ba2I. Syn. Ba′′rii iodi′dum, L.; Iodure de baryum, &c., Fr.
Prep. 1. Dissolve sulphide of barium in water, and add iodine (gradually) in excess; after the reaction is complete, filter, and either evaporate to dryness, or crystallise.
2. Digest freshly precipitated carbonate of barium, in excess, in a hot solution of protiodide of iron; filter and evaporate to dryness; then re-dissolve and crystallise.
3. By saturating hydriodic acid with oxide or carbonate of barium.
Prop., &c. A white or greyish-white mass, or acicular crystals (according to the mode of its preparation); very soluble in water and in alcohol; and decomposed by exposure to the air. It has been highly recommended as an alterative, resolvent, and liquefacient, particularly in scrofula, glandular swellings, chronic inflammations, and the other affections in which chloride of barium and iodine are given.—Dose, 1⁄12th to 1⁄8th gr. (gradually and cautiously increased to 1 gr.), in distilled water, 2 or 3 times a day. Externally, as an ointment (3 or 4 gr., to lard, 1 oz.), as an application to scrofulous swellings. (Biett.) It possesses all the irritant, corrosive, and poisonous properties of the chloride, but in a much more violent degree.
Barium, Nitrate of. Ba(NO3)2. Syn. Nitrate of baryta; Bary′tæ ni′tras, L. Prep. As the acetate or chloride of barium, substituting pure nitric acid for acetic or hydrochloric acid.
Prop., &c. Transparent, colourless octahedrons, which are anhydrous, insoluble in alcohol, and require about 8 parts of cold water, and about 3 parts of boiling water, for solution.
Uses. In chemistry, to prepare baryta, and as a test for sulphuric acid and the soluble sulphates; and in pyrotechny, to give a green tinge to flame.
Barium, Oxalate of. BaC2O4. Syn. Ox′alate of baryta; Bary′tæ ox′alas, L. Prep. By precipitating a barium salt with oxalate of ammonium. Very nearly insoluble.