Alkali cyanide crystals

There have been various attempts to rationalize the phase transitions observed in urea inclusion compounds. One of these approachesdraws an analogy between the phase transition in alkane/urea inclusion compounds and the order-disorder phase transitions in alkali cyanide crystals and proposes that coupling between transverse acoustic phonons of the host structure and the orientational order of the guest molecules provides an indirect mechanism for orientational ordering of the guest molecules in the low-temperature phase. 

Germanium [7440-56-4] M 72.6, m 937 , 925-975 , b 2700 , d 5.3. Copper contamination on the surface and in the bulk of single crystals of Ge can be removed by immersion in molten alkali cyanide under N2. The Ge was placed in dry cyanide powder in a graphite holder in a quartz or porcelain boat. The boat was then inserted into a heated furnace which, after a suitable time, was left to cool to room temperature. At 750°, a 1mm thickness requires about Imin, whereas 0.5cm needs about half hour. The boat was removed and the samples were taken out with plastic-coated tweezers, carefully rinsed in hot water and dried in air [Wang J Phys Chem 60 45 7956]. 

White granular powder or cubic crystals refractive index 2.071 darkens on exposure to hght density 5.56 g/cm Moh s hardness 2.5 melts at 455°C vaporizes at 1,547°C vapor pressure 1 and 5 torr at 912 and 1,019°C insoluble in water, alcohol and dilute acids soluble in ammonia solution and concentrated sulfuric acid, alkali cyanide, ammonium carbonate also soluble in potassium bromide and sodium thiosulfate solutions. 

Red monoclinic crystals or brownish-red powder density 5.625 g/cm insoluble in water soluble in nitric acid, ammonia and solutions of alkali cyanides and chromates. 

Grayish-white hexagonal crystals density 3.95 g/cm decomposes at 320°C insoluble in water, alcohol or dilute acids moderately soluble in concentrated ammonia soluble in concentrated boding nitric acid also soluble in alkali cyanide solutions. 

Light yellow hexagonal crystals or powder darkens on exposure to hght density 5.68 g/cm melts at 558°C vaporizes at 1,506°C insoluble in water, most acids and ammonium carbonate solution moderately soluble in concentrated solutions of alkali chloride, bromide, and thiosulfate readily soluble in solutions of alkali cyanides, iodides and in hot concentrated hydriodic acid. 

Sprik et al, 1993 Signorini et al, 1990), a typical example being the orientational disorder associated with NH in NH Br. Detailed simulations have been reported on (NaCN),, t(KCN),t and other mixed alkali halides and alkali cyanides. Other systems studied include potassium and calcium nitrate crystals and their mixtures. The transition from the crystalline to the superionic conductor phase in solid electrolytes has also been successfully investigated. Molecular dynamics studies of Agl were carried out by Parrinello, Rahman Vashishta (1983). LijSO has been investigated by molecular dynamics by Impey et al. (1985). Here, the Li ions become mobile at high temperatures. The ions exhibit orientational disorder and the orientational... 

Platinum complexes incorporating an optically active amine have been employed for resolution of racemic mixtures of optically active olefins by reaction of the olefin with dichloro-platinum(II). The differing solubility of the diastereoisomers permits separation by fractional crystallization and the olefin can be recovered by reaction of the complex with aqueous alkali cyanide. Using either (-f)-l-phenyl-2-aminopropane (Dexedrine) or (-f)- or (—)-a-phenyl-ethylamine. Cope and co-workers have resolved the optical isomers of trans double bond coordinated and, with (—)-phenylethyl-amine)dichloroplatinum(II), a bridged complex with each double bond coordinated to a different platinum atom. 

All four cyanogen halides are known. The fluoride is a gas at ordinary temperatures and is prepared by pyrolysis of (FCN)3 which in turn is made from (ClChOa and NaF in tetramethylene sulphone. The chloride is a liquid boiling at 14-5°C which readily polymerizes to cyanuric chloride, CI3C3N3, and is prepared by the action of chlorine on metal cyanides or HCN. The bromide and iodide, also prepared from halogens and alkali cyanides, form colourless crystals. All four halides have been studied in the vapour state and all except FCN also in the crystalline state (Table 21.9). 

Properties White or yellow crystals or powder. Soluble in ammonium hydroxide, alkali cyanides almost insoluble in water. 

Crystals Or white powder. Turns brown on beating in air. Very poisonous d 2.226. Soly in water (15°) 1.71 g/100 ml. Slightly sol in ale so] in solns of alkali cyanides or hydroxides not appreciably attacked by nrganic acids, but readily dec by dil mineral acids witb evolution of hydrogen cyanide. Readily forms complex cyanides. 

WUieor yellowish monoclinic crystals or powder. Practically insol in water or dil acids sol in solns of alkali cyanides,... 

Reddish -brown powder or cubic crystals ppts as a colloid or gel. Practically insol in water, dil acids, most organic solvents sol in NH(OH, solns of alkali cyanides. 

White to cream-colored powder, colorless or dark green orthorhomhic crystals, or dark red monoclinic crystals. Poisonous mp 474 . Practically insol in water, alcohol, cold dil acids sol in NH4OH dec by HNO,. boiling dil HCI. Sol in alkali cyanide solns because of formation of stable cyano-cuprateO) ions. 

Dense powder or cubic crystals (zinc-blende structure). Less photosensitive than CuBr or CuCl- mp 588-606 bp about 1290° djs 5.63. Extremely insol in water practically insol in dil acids, alcohol sol in aq solns of NHj, alkali cyanides, thiosulfates, iodides dec by coned HzS04 and HNOj... 

Light yellow, odorless powder slowly darkened by light. Crystals are hexagonal Or cubic, d 5.67 mp 552. Practically insol in water (0.03 mg/l) in acid (except coned HI in which it dissolves readily on heating) in ammonium carbonate. Freely sol in solns of alkali cyanides or iedides 35 mg dissolve in a liter of 10% ammouia appreciably sol in coned solns of alkali bromides, chlorides, thiocyanates, thiosulfates, mercuric and silver nitrates. It is slowly attacked by boiling coned acids, but not affected by hot solns of alkali hydroxides. 

White, amorphous powder or shiny, rhombic prisms. Insoluble in HaO and alcohol. Soluble in alkali cyanides and aqueous ammonia soluble in dilute acids (evolution of HCN). Decomposes at 800 C d 1.852. Crystal structure type C3 (CuaO type). 

The alkali metal cyanides MCN are produced by direct neutralization of HCN they crystallize... 

White powder cubic crystals the mineral marshite is a red-brown crytal density 5.67 g/cm refractive index 2.346 hardness 2.5 Mohs melts at 606°C vaporizes around 1,290°C insoluble in water and dilute acids soluble in aqueous solutions of ammonia and alkali salts of cyanide, iodide and thiosulfate ions. 

Alkali metal salts of such tetracyanonickelate(II) anion may be crystallized from such solutions as hydrates, K2 [Ni(CN)4 3H2O upon evaporation of the solution. In strong cyanide solution, a pentacyano complex anion, red penta-cyanonickelate(ll), [Ni(CN)5] forms. Strong acids decompose cyanonickelate salts, precipitating nickel cyanide. 

Silvery-white lustrous metal when pure or dark gray amorphous powder orthorhombic crystals hardness 2.3 Mohs density 6.25 g/cm melts at 452°C vaporizes at 990°C modulus of elasticity 6.0x10 psi thermal neutron absorption cross section 4.7 0.1 barns insoluble in water, carbon disulfide, and benzene also insoluble in HCl soluble in sulfuric acid, nitric acid, and aqua regia also soluble in caustic potash and in solutions of alkali metal cyanides. 

Cadmium Hydroxide. Cd(OH)2 [21041-95-2] is best prepared by addition of cadmium nitrate solution to a boiling solution of sodium or potassium hydroxide. The crystals adopt the layered structure of Cdl2 there is contact between hydroxide ions of adjacent layers. Cd(OH)2 can be dehydrated to the oxide by gende heating to 200°C it absorbs C02 from the air forming the basic carbonate. It is soluble in dilute acids and solutions of ammonium ions, ferric chloride, alkali halides, cyanides, and thiocyanates forming complex ions. 

The crystal structure of the FenFem(CN)6 grouping is shown in Figure 37. A face-centered cubic lattice of Fe2+ is interlocked with another face-centered cubic lattice of Fe3 + to give a cubic lattice with the corners occupied by iron ions. The CN ions are located at the edges of the cubes between each Fe2+ ion and the neighboring Fe3 + the carbon atom of the cyanide is bonded to the Fe2 + ion and the nitrogen atom is coordinatively bonded to the Fe3 + ion. The alkali-metal ions and water molecules are inside the cubes formed by the iron ions. 

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