Solubilities in liquid ammonia

C12-0045. Ammonia condenses to a liquid at low temperature. What kinds of solids would you expect to be soluble in liquid ammonia ... 

One of the disadvantages of using a nonaqueous solvent is that in most cases ionic solids are less soluble than in water. There are exceptions to this. For example, silver chloride is insoluble in water, but it is soluble in liquid ammonia. As will be illustrated later, some reactions take place in opposite directions in a nonaqueous solvent and water. 

We have already mentioned that silver chloride is readily soluble in liquid ammonia. Because it is slighdy less polar than water and has lower cohesion energy, intermolecular forces make it possible for organic molecules to create cavities in liquid ammonia. As a result, most organic compounds are more soluble in liquid ammonia than they are in water. Physical data for liquid ammonia are summarized in Table 10.2. 

In order for a metathesis reaction to occur in water, some product must be removed from the reaction. Generally, this involves the formation of a precipitate, the evolution of a gas, or the formation of an unionized product. Because solubilities are different in liquid ammonia, reactions are often unlike those in water. Although silver halides are insoluble in water, they are soluble in liquid ammonia as a result of forming stable complexes with ammonia. Therefore, the reaction... 

The first of these reactions takes place because AgCl is insoluble in water. The second takes place because AgCl is insoluble in sulfur dioxide. The third reaction takes place because the highly ionic LiCl is not soluble in liquid ammonia. The last of these reactions takes place because AgCl is soluble in liquid ammonia but NaCl is not. It is clear that metathesis reactions may be different in some nonaqueous solvents. 

Explain why CaCl2 is much less soluble in liquid ammonia than is CuCl2. 

Polyatomic anions of tin can be prepared in solution, using alloys of tin with alkali metals which are remarkably soluble in liquid ammonia. The obtained colored solutions contain the cluster anion [Sng]4, 68a106. Upon treatment with a crown ether in ethylenediamine, crystalline compounds [Na(crypt)+]4[Sn9]4 could be prepared where crypt = N(CH2CH20CH2CH20CH2CH2)3N ... 

The information available is collected in Table XXXI (46,149,157, 160,291,292,305-310). There are remarkably few data for hydroxylic solvents, but a reasonable amount for some aprotic solvents, especially ethers. Cerium tribromide is sparingly soluble in liquid ammonia (278) information on solubilities of tribromides in other inorganic non-aqueous solvents seems entirely lacking. Comparisons between tribromide and trichloride solubilities can readily be made using Tables XXIV to XXXI. 

Phosphorus, iodine and sulphur which are all insoluble in water are soluble in liquid ammonia. Since the amide ion, NH2, is a very strong base, liquid ammonia is a good solvent to obtain a strongly basic medium. 

White monoclinic deliquescent crystals or granules density 1.280 g/cm melts at 116°C highly soluble in water (102 g/100 g at 0°C), solubility rapidly increasing with temperature (i.e., 531 g/100 g at 80°C) soluble in liquid ammonia, alcohol and ether. 

Unstable, decomposes at ambient temperatiu e forms yellow crystals below -18°C hygroscopic soluble in water and alcohol, very soluble in liquid ammonia. 

Crystalline solid forming monochnic crystal hygroscopic melts at 149.6°C decomposes at 170°C density 1.305 g/cm highly soluble in water (128 g/100 mL at 0°C) soluble in liquid ammonia, alcohol, and acetone. 

YeUow or orange monoclinic crystal or powder a red aUotrope modification also known density 3.46 g/cm melts at 310°C bods at 707°C insoluble in water soluble in liquid ammonia and alkalies. 

Soft silvery metal body-centered cubic crystal lattice density 5.24 g/cm melts at 822°C vaporizes at 1,596°C electrical resistivity 81 microhm-cm reacts with water soluble in liquid ammonia. 

Monogermane is a colorless gas density 3.43 g/L at 0°C liquefies at -90°C solidifies at -165°C insoluble in cold and hot waters soluble in liquid ammonia and sodium oxychloride slightly soluble in hot hydrochloric acid. 

Digermane, Ge2He is a colorless volatile liquid density 1.98 g/mL at -100°C boils at 29°C decomposes when heated at 215°C solidifies at -109°C decomposes in water soluble in liquid ammonia. 

Soft silvery-white metal body-centered cubic structure density 0.531 g/cm3 burns with a carmine-red flame, evolving dense white fumes melts at 180.54°C vaporizes at 1,342°C vapor pressure 1 torr at 745°C and 10 torr at 890°C electrical resistivity 8.55 microhm-cm at 0°C and 12.7 microhm-cm at 100°C viscosity 0.562 centipoise at 200°C and 0.402 centipoise at 400°C reacts with water soluble in liquid ammonia forming a blue solution. 

White crystalline solid stable in air nonhygroscopic density l.llg/cm decomposes at about 500°C without melting soluble in water, 19g/100ml at 25°C stable in alkaline solution soluble in liquid ammonia and dimethyl formamide slightly soluble in methanol, 0.7 g/lOOml at 20°C. 

Colorless hexagonal crystals density 1.846 g/cm at 20°C decomposes on heating to produce sodium and nitrogen also decomposes in vacuum soluble in water partially converting to hydrazoic acid, solubdity in water, 41.7 g/lOOmL slightly soluble in alcohol, 0.316g/100mL at 16°C soluble in liquid ammonia. 

The tetrahydrate constitutes colorless monoclinic crystals density 2.20 g/cm3 loses all water of crystallization at 100°C converts to strontium oxide, SrO at 1,100°C very soluble in water, 60.4g/100 mL at 0°C, 206 g/100 mL at 100°C soluble in liquid ammonia very slightly soluble in ethanol and acetone. 

Amination of AT-alkylpyridinium salts with amide ions, which in principle should be easier than the reaction with the parent pyridine, has been little studied. The main reason for this is that solvent selection is difficult. Metal amides are only soluble in liquid ammonia (with which pyridinium salts react easily, vide infra), and pyridinium salts are soluble in solvents that are not suitable for use with metal amides. The A/ -methylacridinium cation undergoes direct imination to give (153) in 35% yield by treatment with potassium amide and iron (III) nitrate in liquid ammonia. Two other products (154) and (155) are also formed, probably by hydrolysis and subsequent disproportionation (Scheme 90). One might question whether sodamide is necessary to the above transformation in light of the fact that quin-olinium, isoquinolinium and certain pyridinium ions give cr-complexes (156), (157) and (158) in liquid ammonia alone at 0 °C (73JOC1949). 

In the procedures described below, lithium alkynylides are used. When R is CH3 or higher alkyl, the use of this cation is clearly preferred for several reasons. In particular the sodium alkynylides are poorly soluble in liquid ammonia. The second reason for choosing the lithium compounds is that the reaction of NaOCH with (an excess of) oxirane affords appreciable amounts of the subsequent product HOCCH2CH2OCH2CH2OH. 

The product is a very pale yellow to cream-colored solid. It is hygroscopic and is soluble in liquid ammonia, with limited solubility and stability in acetonitrile, dimethyl sulfoxide, and dimethylformamide. Water or moisture from the air leads to disproportionation, and so the product must be stored under anhydrous... 

Ammino-cuprous Chlorides.—It has long been known that cuprous chloride is soluble in aqueous ammonia, giving a solution which is capable of absorbing carbon monoxide and hence used in gas analysis. Cuprous chloride is also soluble in liquid ammonia.5... 

These compounds are all unstable and lose ammonia on heating. Silver iodide is readily soluble in liquid ammonia, and on evaporating the solution at —40° to —10° C. white lamellar crystals of monammino-silver iodide separate.1... 

Triammino-silver Nitrate, [Ag(NH3)3]N03.—The compound is formed when silver nitrate is exposed to dry ammonia gas much heat is developed, increase in bulk takes place, and sufficient heat may he produced to fuse the mass.3 It exhibits considerable heat of formation, is soluble in water, and loses ammonia on heating, dissociating at 63° C. under ordinary pressure, and is soluble in liquid ammonia below —10° C.4 Only the diammine exists in solution, the triammine being completely dissociated into the diammine and ammonia. 

Ammino-aluminium Iodides,—Aluminium iodide is soluble in liquid ammonia, forming a colourless solution from which, on cooling to —83° C., a crystalline solid of composition A1I3.20NH3 separates. On rise of temperature it loses ammonia, and at S° to 13° C. the composition is that of hexammino-aluminium iodide, [A1(NII3)6]I3. Weber2 found that aluminium iodide absorbs ammonia gas slowly at first, and on warming a white voluminous powder was formed which contains at least four molecules of ammonia for every molecule of the iodide. It decomposes with loss of ammonia on treatment with water. 

Thallous halides do not absorb ammonia at ordinary temperature, but in liquid ammonia these salts form triannnino-thallous halides of composition [T1(NH3)3]C1, [Tl(NH3)3]Br.1 The triammino-deriva-tives formed are somewhat soluble in liquid ammonia, and the solubility increases with rise of temperature and increase in atomic weight of the halogens. No lower ammino-derivatives are known. Tliallic halides absorb ammonia gas readily. If ammonia gas is passed into an alcoholic solution of thallic chloride, or if dry ammonia gas is passed over dry thallic chloride, the gas is absorbed and a white crystalline substance is formed of composition [T1(NH3)3]C13. The crystals may be washed with alcohol containing ammonia and then with absolute alcohol, and finally dried in vacuo. On coming in contact with water the triammine is decomposed with precipitation of violet-black oxide thus ... 

Ammino-manganous Fluoride.—Manganous fluoride is sparingly soluble in liquid ammonia, a crystalline powder being formed which is probably the sesquiammine, [Mn3(NH3)2]F6. It slowly evolves ammonia, and when heated to a temperature of 1200° C. in an atmosphere of ammonia the fluoride is partially reduced.1... 

Physical Properties. Ammonium thiocyanate [1762-95-4], NH4SCN, is a hygroscopic crystalline solid which deliquesces at high humidities (375,376). It melts at 149°C with partial isomerization to thiourea. It is soluble in water to the extent of 65 wt % at 25°C and 77 wt % at 60°C. It is also soluble to 35 wt % in methanol and 20 wt % in ethanol at 25°C. It is highly soluble in liquid ammonia and liquid sulfur dioxide, and moderately soluble in acetonitrile. 

Sodium and potassium nitrates are soluble in liquid ammonia,38 and the soln. are good electrical conductors. According to F. M. Raoult, the dry salts absorb no ammonia, but a cone. soln. of sodium nitrate dissolves as much ammonia as an equal volume of water, and a cone. soln. of potassium nitrate, more ammonia than water. R. Abegg and H. Riesenfeld found the tension of N, N-, and l 5A-soln. of potassium nitrate in A-soln. of ammonia at 25°, had vap. press. 14 59, 15 61, and 16 75 mm. respectively, when the A-ammonia alone had a vap. press, of 13 45 mm. F. Ephraim prepared lithium tetrammino-nitrate, LiN03.4NH3, as a syrup more stable than the corresponding tetrammino-chloride. The electrical conductivities and the lowering of the f.p. of soln. of potassium nitrate 39 in soln. 

The alkali metals are soluble in liquid ammonia, and certain amines, to give solutions which are blue when dilute. The solutions ate paramagnetic and conduct electricity, the carrier being the solvated electron. In dilute solutions the metal is dissociated into metal ions and ammoniated electrons. The metal ions are solvated in the same way that they would be in a solution of a metal salt in ammonia, and so comparison can be made with, for example, [Na(NH3)4]+I-, the IR and Raman spectra of which indicate a tetrahedral coodination sphere for the metal.39... 

Kraus has shown that many of these compounds of the alkali metals with the less electropositive metals (some of which are soluble in liquid ammonia) possess many of the properties of typical salts. He calls these salts of homoatomic anions. It should be noted that in handbooks or indexes, these compounds are to be found... 

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