Complete Text (Part 21)

colors — white, gray, green, yellow, red, brown, blue, black, purple and rose. Ferrous compounds contain iron with a valence of 2. They are generally white or grayish-white when anhydrous, but green or greenish-blue when hydrous or in water solution. Ferric compounds contain iron with a valence of 3. They are usually nearly white or pale yellow when anhydrous, but red-brown when associated with water. The iron preparations used in medicine are numerous. Among the most common compounds of iron are the fol- lowing: FeCl2, ferrous chloride. Fel2, ferrous iodide. FeH2S05 + 6H20 (commonly written FeS04 + 7H20), ferrous sulphate, or "green vitriol." ' FeH2S05, dried or anhydrous ferrous sulphate. Fe203, ferric oxide. FeCl3, ferric chloride. Fe(OH)3, ferric .hydroxide, commonly misnamed "ferric hydrate." Fe2(S04)3, ferric sulphate. 343. Nickel is a hard silver-white metal, tough, capable of high polish. Its specific weight is 8.9. The principal nickel ore is nickelic arsenide, NiAs. THE HEAVY METALS 215 344. Chromium is a hard, gray, crystalline, infusible powder of the specific weight 7.3. Chromous compounds contain the metal with a valence of 2, as in CrCl2. In chromic compounds the element has a valence of 3, as in Cr203. But potassium dichromate (com- monly misnamed "bichromate") has the composition K2Cr207, and "chromic anhydride" is Cr03, which is commonly misnamed chromic acid. 345. Manganese is a hard, brittle metal, fusible with diffi- culty. It occurs in nature in combination with oxygen. Its specific weight is about 7.5. Manganese is remarkable because of its many different valences. It can apparently have a valence of either 2, 3, 4, 6 or 7. MnO is manganous oxide. Mn203 is manganic oxide. Mn02 is manganese dioxide. MnS04 is manganous sulphate. K2Mn04 is potassium manganate. KMn04 is potassium permanganate. 346. Lead is a soft, gray or bluish- white metal of bright luster when untarnished. Its specific weight is 11.4, and its melting point 330° 0. The principal lead ore is galena, which is PbS. The only water-soluble lead compounds are the acetate and the nitrate. PbO is oxide of lead, familiar in the form of the red "litharge" and the yellow "massicot." "White lead" is a "basic carbonate of lead." "Red lead" or "minium" is Pb304. Lead compounds are poisonous. 347. Copper is reddish, softer than iron but harder than silver, malleable and ductile, capable of high polish. Its specific weight is 8.9, and its melting point about 1090°. 216 A CORRESPONDENCE COURSE IN PHARMACY It is found in large quantities, uncombined, in the great copper mines of the Lake Superior regions and in other places. Copper pyrites is represented by the formula CuFeS2 and is common. Brass is an alloy of copper and zinc. 348. Copper compounds are generally green or blue, but some are white, red, brown or black. Cuprous copper is a monad; cupric copper a dyad. Soluble copper compounds have a nauseous, strongly "metallic" or "brassy," persistent taste, and are poisonous. Among the very common copper compounds are the following : Cu20, cuprous oxide. CuO, cupric oxide. Cu2S, cuprous sulphide. CuS, cupric sulphide. Cu(N03)2, cupric nitrate. CuS04, anhydrous cupric sulphate. CuS04 + 5H20, crystallized cupric sulphate, or "blue vitriol." 349. Mercury is the only metal which is liquid at the ordinary temperatures. It is silver- white, lustrous, and so mobile that it is called "quick silver." Its specific weight is 13.6, and its boiling point 360° C. It freezes at about -40° C. Cinnabar is the crystallized mercuric sulphide found in nature and this constitutes the ore from which the metal is obtained. 350. Mercury compounds are of two classes, according to the valence of the element. Mercurous mercury is a monad, forming mercurous compounds; mercuric mercury is the metal with a valence of 2, forming mercuric compounds. The only water-soluble mercury compounds are mercuric chloride and mercuric cyanide; but the nitrates, both THE HEAVY METALS 217 mercurous and mercuric, can be dissolved in a mixture of nitric acid and water. Mercury compounds have a great variety of colors : color- less, white, scarlet, crimson, gray, yellow, orange red, black and brown. They are poisonous, except when absolutely insoluble. Among the most common mercury compounds are : HgOl, mercurous chloride or "calomel." Hgl, mercurous iodide. HgO, mercuric oxide, which is red if produced "in the dry way," but yellow if made by precipitation. Eed oxide of mercury is often called "red precipitate," but cannot be made by "precipitation" as we now understand that term. HgCl2, mercuric chloride or "corrosive sublimate." Hgl2, mercuric iodide, or "red iodide of mercury." HgS, mercuric sulphide, which is red when crystallized, but black when precipitated, although the black precipitated mercuric sulphide can be converted into a red powder called "vermilion." H2NHgCl is mercuric chloramide, commonly called "white precipitate. ' ' 351. Silver is a beautiful white metal, harder than gold, capable of very high polish, malleable and ductile. . Its specific weight is 10.6, and its melting point about 916° 0. It is the best known conductor of heat and of electricity. Pure silver is called "sterling silver." This metal occurs in nature in the free state, but more freely in the form of sulphide associated with the sulphides of lead and copper. 352. Silver compounds are colorless, white, black, yellow or brown. As silver is univalent, the structure of its compounds is simple : Ag20 is silver oxide. AgOl, silver chloride. 218 A CORRESPONDENCE COURSE IN PHARMACY AgX03, silver nitrate, which, when molded into pencils, is called "lunar caustic." 353. Gold is soft, yellow, capable of extremely high polish, remarkably malleable and ductile. Its specific weight is 19.3. It melts at about 1037° 0. Pure gold does not decompose acids, but it dissolves in the mixture called "aqua regia," which is made of nitric acid and hydrochloric acid, because that mixture contains free chlorine, with which the gold forms a soluble chloride. Gold occurs in nature almost exclusively in the uncombined state. The most common gold compound is the chloride, AuCl3, which is a light yellow, transparent, water-soluble, crystalline solid. 354. Platinum is a grayish-white, lustrous, hard, tough metal, fusible only at a strong white heat. Its specific weight is 21.46. It occurs in nature only in the free state. It dissolves in "aqua regia" to form platinic chloride, PtCl4. 355. Bismuth occurs in nature only in the uncombined state. It is a reddish-white, brittle metal of high luster and well defined crystalline structure. It is not malleable nor ductile. It has the specific weight 9.74. It is easily fused, its melting point being 270° 0. It readily decomposes nitric acid, forming nitrate of bismuth, which is soluble in water mixed with nitric acid, but converted into subnitrate of bismuth by water alone. Bi203 is bismuth oxide. OBiCl is bismuthyl chloride. Bi(N03)3, bismuth nitrate. OBiN03, bismuthyl nitrate, or "subnitrate of bismuth." (OBi)2C03+H20, "subcarbonate of bismuth," or bismuthyl carbonate. 356. Tin is a silver-white, lustrous, soft, malleable metal, of the specific weight 7.3, fusible at 228° C. It occurs in SOLUBILITIES OF COMMON INOKGANIC COMPOUNDS 219 nature in the form of "tin ore" or "tin-stone," which is stannic oxide, Sn02. Tin is not easily oxidized, nor is it affected by organic substances which attack iron, copper, lead, zinc, etc. Hence its great usefulness. "Tin salt" is stannous chloride, SnCl2 + 2H20. XXIV Solubilities of Common Inorganic Chemical Compounds in Water and in Alcohol WATER SOLUBILITIES 357. Potassium Compounds. All are water-soluble and most of them are readily soluble. Deliquescent are the hydroxide, carbonate, cyanate, phos- phate, hypophosphite, acetate and the sulphated potassa. Readily soluble are the bicarbonate, chloride, bromide, iodide, ferricyanide, ferrocyanide, nitrate, tartrate, citrate, salicylate, benzoate and Rochelle salt. Less readily soluble are sulphate in 9.5 parts of water, dichromate in 10 parts of water, permanganate in 16 parts of water and chlorate in 16.7 parts of water. Very sparingly soluble is cream of tartar in 201 parts of water. Nearly insoluble is potassium-platinum chloride. 358. Sodium Compounds. All are soluble except anti- monite, which is nearly insoluble. Very freely soluble are the hydroxide, carbonate, chloride, bromide, iodide, chlorate, sulphate, sulphite, bisulphite, thio-sulphate, nitrate, nitrite, phosphate, hypophosphite, arsenate, acetate, tartrate, citrate, valerate, salicylate and benzoate and Rochelle salt. 220 A CORRESPONDENCE COURSE IN PHARMACY Less readily soluble are bicarbonate in 11.3 parts of water, pyrophosphate in 12 parts of water, borax in 16 parts of water and bitartrate sparingly. 359. Lithium Compounds. All freely soluble in water except the carbonate, which dissolves in 80 parts of water, and the phosphate, which is nearly insoluble. 360. Ammonium Compounds. All officinal ammonium compounds are readily water-soluble, the least soluble being the benzoate and the carbonate, which are soluble in 5 parts of water. 361. Barium Compounds. The nitrate, chloride, bromide, iodide, sulphide and acetate are readily soluble. The hy- droxide is soluble in 20 parts of water. Insoluble are the carbonate, phosphate, sulphate and oxalate. 362. Strontium Compounds. The chloride, bromide and iodide are deliquescent. The acetate, lactate and nitrate are readily soluble. The hydroxide is comparatively sparingly soluble. Insoluble are the carbonate, phosphate, sulphate and oxalate. 363. Calcium Compounds. Deliquescent are the chloride, bromide and iodide. Eeadily soluble are the nitrate, hypo- phosphite, sulphite, acetate, lactate and the sulphurated lime. Sparingly soluble is the hydroxide, which requires from 600 to 700 parts of water for solution, and the sulphate, which is soluble in from 300 to 400 parts of water. Insoluble are the carbonate, oxalate and phosphate. 364. Magnesium Compounds. Eeadily soluble are the chloride, bromide, iodide, nitrate, sulphate, acetate, lactate and the acid citrate. Insoluble are the oxide, hydroxide, carbonate, oxalate and phosphate. 365. Zinc Compounds. Deliquescent are the chloride, bromide and iodide. Eeadily soluble are the sulphate, SOLUBILITIES OF COMMON INORGANIC COMPOUNDS 221 nitrate, acetate, lactate and paraphenolsulphonate. Less readily soluble is the valerate. Insoluble are the oxide, sulphide, phosphide, hydroxide, carbonate, oxalate, phos- phate and oleate. 366. Cadmium Compounds. Soluble are the chloride, bro- mide, iodide, nitrate and sulphate. Insoluble are the oxide, hydroxide, sulphide, carbonate, oxalate and phosphate. 367. Aluminum Compounds. Eeadily soluble are the chloride, bromide, iodide, nitrate, sulphate, acetate, potash alum and ammonia alum. Insoluble are the oxide and hydroxide. 368. Cerium Compounds. Soluble are the chloride, nitrate and sulphate. Insoluble are the oxide, hydroxide, carbonate and oxalate. 369. Cobalt Compounds. The cobaltous salts and halides are deliquescent. Insoluble are the oxides, hydroxides and sulphides. 370. Nickel Compounds. Mckelous sulphate and nickel- ous chloride are soluble. The oxides, hydroxides and sul- phide of nickel are insoluble. 371. Iron Compounds. Very readily water-soluble are ferrous chloride, bromide and iodide, ferrous sulphate and nitrate, ferric chloride and bromide, ferric nitrate, subsul- phate, sulphate, acetate and citrate, and iron alum. The scale-salts of iron are all freely soluble. Less soluble is ferrous lactate, requiring 40 parts of water for solution. The insoluble iron compounds are ferrous and ferric oxides, hydroxides, sulphides, carbonates, oxalates, phos- phates, pyrophosphates, metaphosphates andhypophosphites. 372. Chromium Compounds. Water-soluble are the chlo- rides, chromium sulphate, chromic anhydride, commonly called chromic acid, potassium chromate, potassium dichro- mate and chrome alum. 222 A CORRESPONDENCE COURSE IN PHARMACY 373. Manganese Compounds. Soluble are manganous chloride, bromide, iodide, nitrate and sulphate; also potas- sium manganate and permanganate and sodium perman- ganate. Insoluble are the oxides, hydroxide, carbonate, oxalate, phosphate and sulphide. 374. Lead Compounds. The only readily water-soluble lead compounds are the nitrate, acetate and subacetate. Lead chloride is sparingly soluble. 375. Copper Compounds. The only water-soluble cupric compounds are the chloride, nitrate, sulphate and acetate. 376. Mercury Compounds. All mercurous compounds are insoluble in water, but mercurous nitrate is soluble in a mixture of water and nitric acid. The only water-soluble mercuric compounds are the chlo- ride, which is soluble in 16 parts of water, and the acetate and cyanide. The bromide is soluble in about 200 parts of water, but mercuric nitrate is soluble in a mixture of nitric acid and water. 377. Silver Compounds. The only water-soluble salts are the nitrate and acetate. 378. Gold Compounds. The only water-soluble gold com- pound much in use is the trichloride. 379. Bismuth Compounds. The only water-soluble bismuth compound is citrate of bismuth and ammonium. But the nor- mal bismuth nitrate which is decomposed by water is soluble in glycerin and also in glacial acetic acid without decomposi- tion. It is also soluble in a mixture of nitric acid and water. 380. Antimony Compounds. The only water-soluble anti- mony compound is tartrate of antimonyl and potassium, commonly called tartar emetic. But chloride of antimony is soluble in a mixture of hydrogen chloride and water. 381. Arsenical Compounds. Sodium arsenate is readily soluble. Potassium arsenite is also soluble, as is iodide of arsenic. Arsenous acid is only sparingly soluble. SOLUBILITIES OF COMMON" LSTOKGANIC COMPOUNDS 223 382. Oxides. No metallic oxides are water-soluble, except chromic anhydride and other oxides that react with the water to form either acids or bases. These dissolve by "chemical solution. " 383. Hydroxides. The only freely water-soluble metallic hydroxides are those of the alkali metals. The hydroxides of barium, strontium and calcium are comparatively sparingly or very sparingly soluble. All other metallic hydroxides are insoluble. 384. Chlorides. All metallic chlorides are water-sol- uble except those of silver and lead, mercurous chloride and the chloride of antimony (which is decomposed by water, but soluble in a mixture of hydrochloric acid and water) . Deliquescent chlorides are those of calcium, zinc, ferric chloride and platinic chloride. Eeadily soluble are the chlorides of potassium, sodium, lithium, ammonium, barium, strontium, magnesium, alumi- num and gold. Less readily soluble is mercuric chloride, soluble in 16 parts of water. Nearly insoluble is lead chloride. Insoluble are silver chloride and mercurous chloride. Decomposed by water is antimony trichloride. 385. Bromides. Eeadily soluble are the bromides of potas- sium, sodium, lithium, ammonium, barium, strontium, calcium, magnesium, zinc, aluminum and ferrous and ferric bromide. Soluble, though rather sparingly, are mercuric bromide and bromide of gold. Insoluble are the bromides of silver, lead, and mercurous bromide. 386. Iodides. Freely soluble are the iodides of potassium, sodium, lithium, ammonium, barium, strontium, calcium, 224 A CORRESPONDENCE COURSE IN PHARMACY magnesium, zinc, cadmium, ferrous iodide, manganous iodide and arsenous iodide. Insoluble are the iodides of silver, lead and mercury. 387. Cyanides. Those of the alkali metals are freely soluble. Mercury cyanide is soluble. Silver cyanide is insol- uble. 388. Ferrocyanides and Ferricyanides of the alkali metals are water-soluble. 389. Sulphides. Those of the alkali metals and the alkaline earth metals are freely water-soluble. All sulphides of the heavy metals are insoluble. 390. Hypochlorites of the alkali metals and alkaline earth metals are soluble. 391. Chlorates of potassium and sodium are soluble. 392. Sulphites of potassium and sodium are readily soluble. Those of calcium and magnesium are soluble. 393. Sulphates. All metallic sulphates are soluble, except those of barium, strontium, calcium, lead and mercury. Readily soluble sulphates are those of sodium, ammonium, aluminum and ferric sulphate, also the alums. Soluble are the sulphates of potassium, lithium, magnesium, zinc, ferrous sulphate, manganous sulphate and copper sulphate. Very sparingly soluble is calcium sulphate. Insoluble are the sulphates of barium, strontium and lead. Decomposed by water is sulphate of mercury. 394. Thio-sulphates of potassium and sodium are freely soluble. 395. Sulphated potassa and sulphurated lime are freely soluble. 396. Nitrates. All are water-soluble except those of mercury and bismuth, which are decomposed by water. 397. Nitrites of the alkali metals are soluble. 398. Phosphates, Pyrophosphates and Metaphosphates. The only water-soluble phosphates are those of potassium, SOLUBILITIES OF COMMON INORGANIC COMPOUNDS 225 sodium and ammonium, but some phosphates of the heavy metals, also the phosphates of the alkaline earth metals and magnesium, are soluble in phosphoric acid. 399. Orthophosphates of iron are soluble in orthophosphoric acid, but insoluble in pyrophosphoric or metaphosphoric acid. Pyrophosphates and metaphosphates of iron are insoluble in orthophosphoric acid, but soluble in meta- phosphoric acid. 400. Hypophosphites. Those of the alkali metals and of calcium are water-soluble. Those of the heavy metals are insoluble, or .nearly so. 401. Carbonates. The only water-soluble carbonates are those of potassium, sodium and ammonium. That of lithium is but sparingly soluble. 402. Borates. Borax is soluble. 403. Acetates of the metals are all water-soluble. 404. Valerates. Those of potassium, sodium,, lithium and ammonium are soluble. Valerate of zinc is sparingly so. 405. Oxalates. Only those of the alkali metals and ammo- nium are soluble. 406. Tartrates. The normal tartrates of the alkali metals and ammonium are soluble. Their bitartrates are sparingly soluble. The tartrates of ferryl and potassium, and ferryl and ammonium, and antimonyl and potassium are soluble. 407. Citrates. Those of the alkali metals, ammonium and iron are soluble. Magnesium citrate is soluble in water con- taining much citric acid. Bismuth citrate is insoluble, but citrate of bismuth and ammonium is soluble. 408. Lactates of the alkali metals, calcium, strontium, magnesium, zinc and iron are water-soluble. 409. Salicylates. Those of the alkali metals are alone water-soluble. 410. Phenol Sulphonates. Those of the alkali metals and of barium, calcium and zinc are water-soluble. 22G A CORRESPONDENCE COURSE IN" PHARMACY 411. Benzoates. Those of the alkali metals and of ammo- nium and calcium are water-soluble. 412. Oleates. Only the soaps are water-soluble. 413. The student will find it very useful carefully to memorize the following: All of the officinal compounds of potassium, sodium and ammonium are water-soluble, but cream of tartar is only very sparingly soluble. The hydroxides of potassium, sodium and ammonium are freely soluble. The oxides, hydroxides, sulphides, carbonates, oxalates, phosphates (including pyrophosphates, metaphosphates and orthophosphates), hypophosphites, arsenates, arsenites, sali- cylates, benzoates and oleates of the heavy metals are all insoluble. ALCOHOL SOLUBILITIES 414. A very large proportion of the inorganic chemical compounds are insoluble in alcohol, and especially those that contain much water. Inorganic chemical, compounds which are insoluble in water are also, with scarcely any exception, insoluble in alcohol, but even a large number of the water- soluble inorganic chemicals are insoluble in alcohol. 415. Very soluble (in less than 5 parts of alcohol) are: Hydroxides of potassium, sodium and ammonium.