Salts, crystalline

The alkali amides are stable, crystalline salts the heavy metal amides are often explosive. The amides are the bases of the ammonia system. 

NH2-C0-NH NH2,CH5N30. Colourless crystalline substance m.p. 96" C. Prepared by the electrolytic reduction of nitrourea in 20% sulphuric acid at 10 "C. Forms crystalline salts with acids. Reacts with aldehydes and ketones to give semicarbazones. Used for the isolation and identification of aldehydes and ketones. 

Physical properties. Majority are liquids except p toluidine and 1- and 2-naphthylamine. All are colourless when pure, but rapidly darken on exposure to air and light. All are very sparingly soluble in water, but dissolve readily in dilute mineral acids (except the naphthyl-amines, which are only moderately soluble in adds). They form colourless crystalline salts e.g., CjHjNH2,HCl) which are soluble in water these aqueous solutions usually have an add reaction owing to hydrolysis, and give the reactions of both the amine and the acid from which they are derived. Addition of alkali to the acid solution liberates the amine. 

Note. PRIMARY ALIPHATIC AMINES. The lower amines are gases or low-boiling liquids (b.ps. CHjNH, 7 CiHjNH, 17 CH,(CH2,>,NH 49 (CHg)jCHNHa, 34 ) but may be encountered in aqueous or alcoholic solution, or as their crystalline salts. They are best identified as their benzoyl, or toluene-/>-sulphonyl derivatives (c/. (C) above), and as their picrates when these are not too soluble. This applies also to benzylamine, CjHsCHjNH, b.p. 185 also to ethylenediamine, usually encountered as the hydrate, NHj (CHj)j NH2,HjO, b.p. 116 , for which a moderate excess of the reagent should be used to obtain the di-acyl derivative. (M.ps., pp. 55 55 )... 

Synthesis of (A) started with the combination of 2,4,6-trimethylphenol and allyl bromide to give the or/Ao-allyl dienone. Acid-catalyzed rearrangement and oxidative bydroboration yielded the dienone with a propanol group in porlactone ring were irons in the product as expected (see p. 275). Treatment with aqueous potassium hydroxide gave the epoxy acid, which formed a crystalline salt with (R)-l-(or-naphthyl)ethylamine. This was recrystallized to constant rotation. 

Solid Compounds. The tripositive actinide ions resemble tripositive lanthanide ions in their precipitation reactions (13,14,17,20,22). Tetrapositive actinide ions are similar in this respect to Ce . Thus the duorides and oxalates are insoluble in acid solution, and the nitrates, sulfates, perchlorates, and sulfides are all soluble. The tetrapositive actinide ions form insoluble iodates and various substituted arsenates even in rather strongly acid solution. The MO2 actinide ions can be precipitated as the potassium salt from strong carbonate solutions. In solutions containing a high concentration of sodium and acetate ions, the actinide ions form the insoluble crystalline salt NaM02(02CCH2)3. The hydroxides of all four ionic types are insoluble ... 

Ammonium fluoride is a white, deflquescent, crystalline salt. It tends to lose ammonia gas to revert to the more stable ammonium bifluoride. Its solubiUty in water is 45.3 g/100 g of H2O at 25°C and its heat of formation is —466.9 kJ/mol ( — 116 kcal/mol). Ammonium fluoride is available principally as a laboratory reagent. If it is needed in large quantities, one mole of aqueous ammonia can be mixed with one mole of the more readily available ammonium bifluoride (1). 

Properties. Other names for potassium bifluoride are potassium hydrogen difluoride and potassium acid fluoride. This white crystalline salt is a soft, waxy soHd. The crystal forms of potassium bifluoride are tetragonal and cubic (21). The bifluoride ion in KHF2 averages 0.2292 nm between fluoride... 

Stannous fluoride [7783-47-3] Snp2, is a white crystalline salt that has mp 215°C (1), bp 850°C, and is readily soluble in water and hydrogen fluoride. At 20°C stannous fluoride dissolves in water to a concentration of 30—39% in anhydrous hydrogen fluoride to 72—82% (2—4). 

The chlorides, bromides, nitrates, bromates, and perchlorate salts ate soluble in water and, when the aqueous solutions evaporate, precipitate as hydrated crystalline salts. The acetates, iodates, and iodides ate somewhat less soluble. The sulfates ate sparingly soluble and ate unique in that they have a negative solubitity trend with increasing temperature. The oxides, sulfides, fluorides, carbonates, oxalates, and phosphates ate insoluble in water. The oxalate, which is important in the recovery of lanthanides from solutions, can be calcined directly to the oxide. This procedure is used both in analytical and industrial apptications. 

Properties. Nickel sulfate hexahydrate [10101 -97-0], NiSo 6H20 is a monoclinic emerald-green crystalline salt that dissolves easily in water and in ethanol. When heated, it loses water and above 800°C decomposes into nickel oxide and SO3. Its density is 2.03 g/cm. ... 

Nickel Carbonate. Nickel carbonate [3333-67-3], NiCO, is a light-green, rhombic crystalline salt, density 2.6 g/cm, that is very slightly soluble in water. The addition of sodium carbonate to a solution of a nickel salt precipitates an impure basic nickel carbonate. The commercial material is the basic salt 2NiCo2 3Ni(OH)2 4H20 [29863-10-3]. Nickel carbonate is prepared best by the oxidation of nickel powder in ammonia and CO2. Boiling away the ammonia causes precipitation of pure nickel carbonate (32). 

There are a considerable number of stable crystalline salts of the ammonium ion [14798-03-9] NH. Several are of commercial importance because of large scale consumption in fertiliser and industrial markets. The ammonium ion is about the same size as the potassium and mbidium ions, so these salts are often isomorphous and have similar solubiUty in water. Compounds in which the ammonium ion is combined with a large, uninegative anion are usually the most stable. Ammonium salts containing a small, highly charged anion generally dissociate easily into ammonia (qv) and the free acid (1). At about 300°C most simple ammonium salts volatilize with dissociation, for example... 

Technical grade ammonium chloride is widely available as the crystalline salt technical rods and granules are also available. In June 1991, the price of the technical salt was quoted as 0.43/kg. Its DOT number is NA9085. 

Physical and Chemical Properties. Ammonium nitrate is a white, crystalline salt, df = 1.725, that is highly soluble in water, as shown in Table 3 (7). Although it is very hygroscopic, it does not form hydrates. This hygroscopic nature compHcates its usage in explosives, and until about 1940, was a serious impediment to its extensive use in fertilizers. The soHd salt picks up water from air when the vapor pressure of water exceeds the vapor pressure of a saturated aqueous ammonium nitrate solution (see Table 4). 

Ammonium sulfate [7783-20-2], (NH 2 U4, is a white, soluble, crystalline salt having a formula wt of 132.14. The crystals have a rhombic stmcture d is 1.769. An important factor in the crystallization of ammonium sulfate is the sensitivity of its crystal habit and size to the presence of other components in the crystallizing solution. If heated in a closed system ammonium sulfate melts at 513 2° C (14) if heated in an open system, the salt begins to decompose at 100°C, giving ammonia and ammonium bisulfate [7803-63-6], NH HSO, which melts at 146.9°C. Above 300°C, decomposition becomes more extensive giving sulfur dioxide, sulfur trioxide, water, and nitrogen, in addition to ammonia. 

Physical Properties. Both (1) and (2) are weak bases, showing 4.94 and 5.40, respectively. Their facile formation of crystalline salts with either inorganic or organic acids and complexes with Lewis acids is in each case of considerable interest. Selected physical data for quinoline and isoquinoline are given in Table 1. Reference 4 greatly expands the range of data treated and adds to them substantially. 

Strontium Acetate. Strontium acetate [543-94-2] Sr(CH2C02)2, is a white crystalline salt with a specific gravity of 2.1, and it is soluble to the... 

Peroxidic Compounds. When hydrogen peroxide is added to a solution of titanium(IV) compounds, an intense, stable, yellow solution is obtained, which forms the basis of a sensitive method for determining small amounts of titanium. The color probably results from the peroxo complex [Ti(02)(0H)(H20)J, and crystalline salts such as K2[Ti(02)(S0 2] H20 can be isolated from alkaline solutions. The peroxo ligand is bidentate the two oxygen atoms ate equidistant from the titanium (98). 

Amorphous Sb2S2 can be prepared by treating an SbQ solution with 442S or with sodium tliiosulfate, or by heating metallic antimony or antimony trioxide with sulfur. Antimony trisulfide is almost iasoluble ia water but dissolves ia concentrated hydrochloric acid or ia excess caustic. In the absence of air, Sb2S2 dissolves ia alkaline sulfide solutions to form the tliioantimonate(III) ion [43049-98-5], SbS 2, in the presence of air the tetratliioantimonate(V) ion [17638-29-8], SbS , is formed. The lemon-yellow crystalline salt, Na SbS 94420, known as Schhppe s salt [1317-86-8], contains the tetrahedral tetratliioantimonate(V) ion. 

Barium is a member of the aLkaline-earth group of elements in Group 2 (IIA) of the period table. Calcium [7440-70-2], Ca, strontium [7440-24-6], Sr, and barium form a closely aUied series in which the chemical and physical properties of the elements and thek compounds vary systematically with increa sing size, the ionic and electropositive nature being greatest for barium (see Calcium AND CALCIUM ALLOYS Calcium compounds Strontium and STRONTIUM compounds). As size increases, hydration tendencies of the crystalline salts increase solubiUties of sulfates, nitrates, chlorides, etc, decrease (except duorides) solubiUties of haUdes in ethanol decrease thermal stabiUties of carbonates, nitrates, and peroxides increase and the rates of reaction of the metals with hydrogen increase. 

Bismuth citrate [813-93-4]—The synthetically prepared crystalline salt of bismuth and citric acid, principally BiC H O. ... 

Analytical applications of pyrazolones have been reviewed by Busev et al. (65RCR237). Organic bases are easily characterized by formation of highly crystalline salts with picrolonic acid (l-(4-nitrophenyl-3-methyl-4-nitro-5-hydroxypyrazole). The last-named compound is used as a reagent for alkaloids, tryptophan, phenylalanine and for the detection and estimation of calcium (B-76MI40404). 

A. Silver trifluoroacetate. To a suspension of 187 g. (0.81 mole) of silver oxide (Note 1) in 200 ml. of water is added 177 g. (1.55 moles) of trifluoroacetic acid (Note 2). The resulting solution is filtered, and the filtrate is evaporated to dryness under reduced pressure. The dry silver trifluoroacetate thus obtained is purified by placing it in a Soxhlet thimble and extracting with ether, or by dissolving the salt in 1.2 1. of ether, filtering through a thin layer of activated carbon, and evaporating the filtered ether solution to dryness. The yield of colorless crystalline salt obtained after removal of the ether is 300 g. (88%). 

The existence of the nitronium ion in sulfuric-nitric acid mixtures was demonstrated both by cryoscopic measurements and by spectroscopy. An increase in the strong acid concentration increases the rate of reaction by shifting the equilibrium of step 1 to the right. Addition of a nitrate salt has the opposite effect by suppressing the preequilibrium dissociation of nitric acid. It is possible to prepare crystalline salts of nitronium ions, such as nitronium tetrafluoroborate. Solutions of these salts in organic solvents rapidly nitrate aromatic compounds. ... 

The formation of acyl halide-Lewis acid complexes have been observed by several methods. For example, both 1 1 and 1 2 complexes of acetyl chloride, with AICI3 can be observed by NMR spectroscopy. The existence of acylium ions has been demonstrated by X-ray diffraction studies on crystalline salts. For example, crystal structure determinations have been reported for /i-methylphenylacylium and acetylium ions as SbFg salts. There is also a good deal of evidence from NMR measurements which demonstrates that acylium ions can exist in nonnucleophilic solvents. " The positive charge on acylium ions is delocalized onto the oxygen atom. This delocalization is demonstrated in particular by the short O—C bond lengths in acylium ions, which imply a major contribution from the structure having a triple bond ... 

M. and M. Polonovski found that when scopolamine is treated with hydrogen peroxide, there is formed in addition to scopolamine iV-oxide [a]i, — 14° (H2O), [B. HBr, m.p. 153°] the quaternary base scopinium, isolated in the form of its bromide, m.p. 209-10°. The latter is reduced by sodium amalgam to a tertiary base, stereoisomeric with scopine and related to the latter as -tropine is to tropine and, therefore, named -SCOPINE. It yields crystalline salts B. HCl, m.p. 257-8°, aurichloride. 

Santos Isolated anonaine from A. reticulata L., and A. squamosa L. (custard apple), while from A. triloba L. (Asimina triloba Dun.), Lloyd, and later Fletcher, obtained asiminine, itself amorphous, but yielding crystalline salts. Recently Manske has isolated from this species the crystalline alkaloid anolobine. 

B. H2SO4. lOHjO, fine colourless needles, m.p. 312° (dec.), from boiling water. No other crystalline salt was obtained. The base contains one — OMe and one = NMe group. 

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