4146. Sulphate of Iron

4146.    Sulphate of Iron. Commercial sulphate of iron is known also as Copperas, Green Vitriol, Shoemakers' Black, etc.. For medicinal purposes it requires some preparation : Mix 1 fluid ounce sulphuric acid with 4 pints water; add 4 pounds commercial sulphate of iron, and 1 ounce iron wire; digest with heat and occasional agitation until the sulphate is dissolved; strain while hot, and set aside so that crystals may form; evaporate the mother-liquor for more crystals, and dry the whole. (Cooley.)

4147. Sulphuret of Iron

4147.      Sulphuret of Iron. Mix together 4 parts sublimed sulphur, and 7 parts iron filings. Heat in a crucible in a common fire till the mixture begins to glow; then remove the crucible from the fire, and cover it up until the reaction is at an end and the whole has become cold.

4148. Bisulphuret of Iron

4148.    Bisulphuret of Iron. This is found in large quantities in mineral form, and is known as Iron pyrites. It may also be obtained by projecting a mixture of 5 parts sulphur, and 4 parts iron filings, into a red-hot crucible, excluding the air as much as possible. It melts easily, and takes sharp casts, and may be colored red with vermilion.

4149. Hydrated Protosulphuret of Iron

4149.    Hydrated Protosulphuret of Iron. This is a black, insoluble substance, rapidly decomposed by exposure to the air. A neutral solution of protosulphate of iron made with recently boiled or distilled water, is precipitated by adding a solution of hydrosulphuret of ammonia, or of sulphuret of potassium. Collect the precipitate on a filter, wash it as quickly as possible with recently boiled water, squeeze in a linen cloth, and preserve in its pasty state under water.

This preparation of iron is proposed by Mialhe as an antidote to the salts of arsenic, antimony, bismuth, lead, mercury, etc., and to arsenious acid, more especially to white arsenic and corrosive sublimate. On contact with the latter substance it is instantly converted into protochloride of iron and sulphuret of mercury, two comparatively inert substances.

4150. Hydrated Persulphuret of Iron

4150.       Hydrated Persulphuret of Iron. Prepared by adding, very gradually, a diluted solution of sulphuret of potassium, or of hydrosulphuret of ammonia, to a neutral solution of persulphate of iron, collecting, etc., the precipitate, in the same way as in hydrated protosulphuret of iron. Bouchardat and Sandras recommend this persulphuret as a substitute for the protosulphuret, to which, they say, it id preferable.

4151. Protoxide of Iron

4151.    Protoxide of Iron. Dry protoxide of iron is a black powder; in its hydrated state it is white, and when exposed to the air rapidly absorbs oxygen, assuming first a greyish-green color, and then a brownish-red, which is much brightened by exposure to a red heat, at the same time that its solubility in acids fa considerably lessened. The salts of protoxide of iron have a greenish color, but yield nearly colorless solutions, except when concentrated. The white hydrate is precipitated from solutions of tho protosalts of iron by the pure alkalies. (Cooley.)