Calcium cyanide General

The resulting melt is cooled lapidly to prevent reversion to calcium cyanamide. The product is marketed in the form of flakes, dark gray because of the presence of carbon. Typical composition is shown in Table 7. Because the rate of hydrogen cyanide evolution is relatively high, it is readily adaptable to fumigation. Specific gravity of the product is 1.8 to 1.9. The price of black cyanide is generally lower than sodium cyanide it is manufactured in Canada and South Africa. 

The chlorides, bromides, iodides, and cyanides are generally vigorously attacked by fluorine in the cold sulphides, nitrides, and phosphides are attacked in the cold or may be when warmed a little the oxides of the alkalies and alkaline earths are vigorously attacked with incandescence the other oxides usually require to be warmed. The sulphates usually require warming the nitrates generally resist attack even when warmed. The phosphates are more easily attacked than the sulphates. The carbonates of sodium, lithium, calcium, and lead are decomposed at ordinary temp, with incandescence, but potassium carbonate is not decomposed even at a dull red heat. Fluorine does not act on sodium bofate. Most of these reactions have been qualitatively studied by H. Moissan,15 and described in his monograph, Lefluor et ses composes (Paris, 1900). 

The general methods for the production of the alkali metals are (1) Electrolytic processes involving the electrolysis of (a) the fused hydroxide, or (b) a fused salt— chloride, nitrate, cyanide, etc. (2) Chemical processes involving the reduction of hydroxide, or carbonate, or other salt with carbon, metal carbide, iron, calcium, magnesium, aluminium, etc. W. Spring 5 claims to have reduced a little potassium chloride by passing hydrogen over the salt at a red heat. 

Cyanogen derivatives arc numerous and capable of great complexity. Platinous cyanide Pt(CN)3, is obtained as a yellow precipitate when mercuric cyanide is added to a solution of alkali chlorplatinite. Double cyanides of the general formula M 2Pt(CN)4 are formed by such reactions as 6 KCN + PtCL = K2Pt(CN) + 4 KC1 + (CN),. These platino-cyanides do not respond to the ordinary tests for platinum. These compounds yield beautifully colored hydrates, and the barium and calcium hydrates have optical isomeric modifications.2 Certain of these hydrates become remarkably fluorescent under excitation from ultraviolet light or radium. 

The addition of cyanide to simple aldoses is essentially quantitative in solutions buffered at pH 9.1 increased acidity causes diminished reaction rates. The reaction can be conveniently effected using a solution of sodium cyanide and calcium chloride, but varied conditions may be required in order to obtain desired proportions of the epimeric products. The latter arise from the creation of a new asymmetric center, and are generally not produced in equal amoimts because of the asymmetric nature of syntheses using optically active starting materials. The epimeric preference may be so high as to give essentially quantitative yields of one product. For ex-... 

Binary salts have varying hazards, one of which is toxicity. Some of the binary salts are highly toxic, such as sodium fluoride, calcium phosphide, and mercuric chloride. Cyanide salts are also highly toxic, such as sodium cyanide and potassium cyanide. The remaining salts, binary oxides, peroxide, hydroxides, and oxysalts are generally not considered toxic. 

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