Feii = 55.84. Fe2vi = 111.68.

The element iron (AS, iren, Goth. iarn, metal; L. ferrum) is the most useful and abundant of the heavier metals, being present in nearly all rocks, soils, animal and plant ashes, but seldom in the pure state. It occurs as sulphide - iron pyrites, FeS2; as oxide - magnetic iron ore, FeO,Fe2O3; red hematite, Fe2O3; as carbonate - spathic iron ore, FeCO3, and also combined with mineral acids. From any of these ores the metal may be obtained by reducing with carbon, which consists in heating in a blast furnace iron ore, coke, or coal, and some flux, as limestone or clay. This latter forms a more fusible aluminum and calcium silicate or slag. (1) Fe2O3 + 3C = 2Fe + 3CO. (2) FeCO, + C = Fe + CO2 + CO. (3) FeS2 + O4 = Fe + 2SO2. As such it is known as cast or pig iron, and is not pure by reason of its containing traces of silicon, sulphur, phosphorus, and carbon, 2-5 p. c. By puddling or refining, the carbon combines with a blast of oxygen and is blown out, leaving wrought or bar iron, having still present carbon .03-.3 p. c. Steel is a product intermediate between these two, containing carbon .5-2 p. c. Iron is hard, malleable, ductile, tenacious, grayish, fibrous texture; taste slightly styptic, odor slight, magnetic, sp. gr. 7.7, least fusible of all useful metals excepting platinum, readily oxidizes in moisture and forms two kinds of salts, ferrous (lower) and ferric (higher). The metal itself and many important salts are official.

Tests for Iron Salts: 1. Ferrous salt with potassium ferrocyanide gives a nearly white precipitate, turning blue on exposure to air; with ferric salt have deep blue color at once - Prussian blue. 2. Ferrous salt with potassium ferricyanide gives at once deep blue color - Turn-bull's blue; with ferric salts have greenish-olive color. 3. Ferrous salt with tannin has no effect; with ferric salt have greenish-black precipitate - ferric tannate (ink). 4. Ammonium sulphide gives black precipitate with both kinds of salts. 5. Ferrous salts with ammonia water give whitish precipitate, turning green, then black, finally brown; with ferric salts have precipitate of brown ferric hydroxide.

Ferrum. Iron. - (Syn., Ferr., Iron wire,. Mars; Fr. Fer (metallique), Fil de Fer; Ger. Eisen, Eisendraht.) Metallic iron in the form of fine, bright, and non-elastic wire; the grease or paraffin oil used in coating for protection against moisture and oxidation (rust) should be removed previous to use. Wire in form of card teeth wastings is most convenient purest, and cheapest.

Preparations. - (Unoff.): Liquor Ferri Protochloride, 16 p. c, + hydrochloric acid 62.5, glycerin 25, dil. hypophosphorous acid 1, dist. water q. s. 100. Syrupns Ferri et Mangani lodidi - iodine 8.15 Gm., iron wire 2.8, manganese sulphate 2.65, sodium iodide 3.56, +. Syrupus Ferri Phosphatis (Br.), each 3j (4 Ml. (Cc.)) contains 1 gr. (.06 Gm.) ferrous phosphate, dose, 3ss-l (2-4 Ml. (Cc.)). Vinum Ferri (Br.), 5 p. c. + sherry wine, dose, 3j-4 (4-15 Ml. (Cc.)).

Ferrum Reductum. Reduced Iron. - (Syn., Ferr. Reduct., Ferrum Redactum, Iron (reduced) by Hydrogen, Quevenne's Iron, Powder of Iron, Ferrum Hydrogenio Reductum, Ferrum Ope Hydrogenii Paratum; Fr. Fer reduit par l'Hydrogene; Ger. Reduziertes Eisen.)

Manufacture: Freshly prepared ferric hydroxide (or subcarbonate), thoroughly washed and dried, is put into the central portion of a glass tube, the ends being filled with asbestos and corked, each cork being perforated by a smaller glass tube; the tube is put into a furnace and brought to red heat. Through this tube now is passed pure dry hydrogen, made from zinc and H2SO4, which is continued until furnace and tube have cooled - Fe2O3 + 6H + heat = 2 Fe + 3H2O. It is a very fine, grayish-black, lustreless powder, odorless, tasteless, permanent, insoluble in water, alcohol, heated in air ignites and glows, being converted into black ferroso-ferric oxide; contains 90 p. c. of metallic iron, Fe. Tests: 1. Shake with distilled water (5) - liquid does not change color of litmus. Impurities: Arsenic, sulphide, etc. Should be kept in well-closed containers. Dose, gr. 1-5 (.06-.3 Gm.), at mealtime, in pill, wafer.

Preparations. - (Unoff.): Trochiscus Ferri Redacti (Br.), each 1 gr. (.06 Gm.). Extraction Ferri Pomatum, 4 p. c, + fresh apple juice 100, heat, evaporate to pilular consistence, dose, gr. 5-15 (.3-1 Gm.). Pilulae Ferri, Quininae, Strychninae et Arseni Mites - reduced iron 4.5 Gm., quinine sulphate 6.5, strychnine .13, arsenic trioxide .13, clarified honey q. s. 100 pills. Pilulae Ferri, Quininae, Strychninae et Arseni Fortiores: reduced iron 6.5 Gm., quinine sulphate 6.5, strychnine .32, arsenic trioxide .32, clarified honey q. s. 100 pills. Tinctura Ferri Pomata - ferrated extract of apples 10, alcohol 10, cinnamon water q. s. 100.

Properties and Uses. - Originally this was prepared as a substitute for the ferri subcarbonas, by Quevenne, of Paris. It is a chalybeate tonic, but very prone to derange the stomach, owing to formation of H2S from the impurities.

Liquor Ferri Chloridi. Solution of Ferric Chloride. - (Syn., Liq. Ferr. Chlor., Solution of Iron Perchloride, Liquor Ferri Muriatici Oxydati, Ferrum Sesquichloratum Solutium; Br. Liquor Ferri Perchloridi Fortis; Fr. Solute de Perchlorure de Fer, Chlorure ferrique liquide; Ger. Liquor Ferri sesquichlorati (Flussiges), Eisenchlorid-losung.)

Manufacture: To a flask containing iron wire 12.5 Gm. add hydrochloric acid 42 Gm. diluted with distilled water 25 Ml. (Cc), heat on water-bath until effervescence ceases (1 1/4 hours), boil, filter, rinse flask and iron wire with little hot distilled water; to filtered liquid, including rinsings, add hydrochloric acid 22 Gm. and this mixture in a slow stream to nitric acid 6.5 Gm., warm gently; after effervescence ceases, heat until free from nitric acid; if solution black add nitric acid in drops until red fumes no longer escape, finally add hydrochloric acid 4 Gm., and distilled water q. s. 100 Gm. It is a reddish-brown aqueous liquid, faint odor of hydrochloric acid; an acid, strongly styptic taste, acid reaction, sp. gr. 1.30; contains ferric chloride, FeCl3, corresponding to 10-11 p. c. of iron. Tests: 1. Aqueous solution (1 in 10); with ammonia water - brownish-red precipitate; with potassium ferro-cyanide T. S. - blue precipitate; with silver nitrate T. S. - white precipitate, insoluble in nitric acid. Impurities: Zinc, copper, lead, salts of fixed alkalies, ferrous salts, free hydrochloric acid, nitric acid. Should be kept dark, in glass-stoppered bottles. Dose, eij-10 (.13-.6 Ml. (Cc.)), well diluted with water or syrup.