Cyanides calcium cyanide

Hydrogen cyanide Calcium cyanide Potassium cyanide Sodium cyanide Hydrogen fluoride as F Hydrogen peroxide Hydrogen selenide as Se Hydrogen sulphide Hydroquinone... 

Inorganic cyanides Barium cyanide, calcium cyanide, cyanogen chloride, silver cyanide... 

Amounts allowed range from 5 ppm in cucumbers, lettuce, radishes, and tomatoes, to 250 ppm in spices. EPA also requires industries to report spills of 1 pound or more of potassium silver cyanide and 10 pounds or more of hydrogen cyanide, potassium cyanide, sodium cyanide, calcium cyanide, or copper cyanide. 

Characteristic Hydrogen cyanide Sodium cyanide Potassium cyanide Calcium cyanide... 

Cyanides (reported as cyanide, hydrogen cyanide, sodium cyanide, potassium cyanide, calcium cyanide, or copper(I) cyanide) have been detected in air samples collected at 5 of the 406 hazardous waste sites where cyanides have been detected in some environmental medium (HazDat 1996). The HazDat information used includes data from both NPL and other Superfund sites. No information was found on detections of cyanogen, cyanogen chloride, or thiocyanates in air at any NPL or other Superfimd hazardous waste sites (HazDat 1996). 

Cyanide occurs most commonly as hydrogen cyanide in water, although it can also occur as the cyanide ion, alkali and alkaline earth metal cyanides (potassium cyanide, sodium cyanide, calcium cyanide), relatively stable metallocyanide complexes (ferricyanide complex [Fe(CN)6]-3), moderately stable metallocyanide complexes (complex nickel and copper cyanide), or easily decomposable metallocyanide complexes (zinc cyanide [Zn(CN)2], cadmium cyanide [Cd(CN)2]). Hydrogen cyanide and cyanide ion combined are commonly termed free cyanide. The environmental fate of these cyanide compounds varies widely (Callahan et al. 1979). 

Guidelines a. Air ACGIH Threshold Limit Values for Occupational Exposure (TLV-TWA) Cyanogen TLV - Ceiling Hydrogen cyanide, sodium cyanide, calcium cyanide, potassium cyanide, acetone cyanohydrin Cyanogen chloride 21 mg/m3 5 mg/m3 0.75 mg/m3 ACGIH 1996... 

Synonyms/compounds Sodium cyanide potassium cyanide calcium cyanide ( black cyanide )... 

Cupriethylenediamine Solution Cupriethylenediamine Solution Copper Cyanide Copper Iodide Cyanoacetic Acid Potassium Cyanide Calcium Cyanide Cyanoacetic Acid Benzonitrile Ethylene Cyanohydrin Acrylonitrile... 

Calcium Cyanide Calcium Cyanide Carbolic Oil Carbolic Oil... 

In cyanidation, the ground ore is leached with a solution of sodium cyanide (0.02—0.05%) or an equivalent of calcium cyanide together with some lime. The leaching solution is aerated to provide oxygen and gold is dissolved with formation of sodium dicyanoauratae(-l) [15280-09-8] 5 2l(J u(C2>5)[) (see... 

Tetrasodium hexakiscyanoferrate decahydrate [14434-22-1], Na4[Fe(CN)g] IOH2O, or yellow pmssiate of soda, forms yellow monoclinic crystals that are soluble in water but insoluble in alcohol. It is slightly efflorescent at room temperature, but the anhydrous material, tetrasodium hexakiscyanoferrate [13601 -19-9], Na4[Fe(CN)J, is obtained at 100°C. The decahydrate is produced from calcium cyanide, iron(II) sulfate, and sodium carbonate in a process similar to that for the production of K4[Fe(CN)g] 3H2O. It is used in the manufacture of trisodium hexakiscyanoferrate, black and blue dyes, as a metal surface coating, and in photographic processing. 

Calcium cyanamide can be converted to calcium cyanide [592-01-8], used ia cyanidation of metallic ores and production of sodium cyanide and ferrocyanides (11) (see Cyanides). Calcium cyanamide has also been used to make cyanamide which ia turn is the starting material for important iadustrial organic syntheses. 

In North America, calcium cyanamide is no longer used as fertiliser, but it has limited use in special agricultural appHcations for defoHants, fungicides, herbicides, and as a weed killer. The primary industrial use is as a chemical intermediate for the manufacture of calcium cyanide, hydrogen cyanamide solution, and dicyandiamide. Calcium cyanamide is also used to add nitrogen to steel. 

Industrial uses make up most of the market for cyanamide. Calcium cyanamide is used directly for steel nitridation (34) and to some extent for desulfurization (36) (see Steel). Cyanamide is used to produce cationic starch (36) and calcium cyanide. Cyanamide is, of course, the raw material for dicyandiamide and melamine. New uses include intermediates for pesticides, detergents (37), medicines such as antihistamines, hypertension, sedatives, contraceptives, etc (38), the photography industry (39), as an additive for fuels and lubricants, as a paper preservative, and as a cement additive. 

Ammonium cyanide may be prepared in solution by passing hydrogen cyanide into aqueous ammonia at low temperatures. It may also be prepared from barium cyanide and ammonium sulfate, or calcium cyanide with ammonium carbonate. It may be prepared in the dry state by gentiy heating a mixture of potassium cyanide or ferrocyanide and ammonium chloride, and condensing the vapor in a cooled receiver. Ammonium cyanide is soluble in water or alcohol. The vapor above soHd NH CN contains free NH and HCN, a very toxic mixture. 

Cmde calcium cyanide [592-01-8] about 48 to 50 eq % sodium cyanide, is the only commercially important alkaline-earth metal cyanide, and output toimage has been greatiy reduced. This product, commonly called black cyanide, is marketed in flake form as a powder or as cast blocks under the trademarks Aero and Cyanogas of the American Cyanamid Co. 

Physical and Chemical Properties. Because of decomposition, the melting point of calcium cyanide can only be estimated by extrapolation to be 640°C (70). 

Aqueous solutions of calcium cyanide prepared even at low temperature turn yellow or brown owing to the formation of HCN polymer. Calcium cyanide hydroly2es readily. 

The presence of brown polymer in soHd form is sometimes noted even in dry calcium cyanide that has been stored for long periods. Calcium cyanide is decomposed by carbon dioxide, acids, and acidic salts Hberating hydrogen cyanide. 

With sulfur in aqueous medium, calcium cyanide forms calcium thiocyanate [2092-16-2]... 

Manufacture. Calcium cyanide is made commercially from lime [1305-78-3], CaO, coke, and nitrogen. The reactions are carried out in an electric furnace (69). 

Hexacyanobenzene [1217-44-33] benzenehexacarbonitnle, is prepared from 2,4,6-tnfluorobenzene-l,3,5-tricarbonitrile [3638-97-9] by substitution with calcium cyanide (48,49). It forms colored TT-complexes with aromatic hydrocarbons. 

Calcium cyanide Ca(CN)2 Reacts with air moisture to release HCN. If finely ground and the relative humidity of the air is >35%, this can occur fairly rapidly Releases HCN slowly on contact with water or CO2, or rapidly with acids Do not handle with bare hands Nonflammable white powder or crystals... 

Aero Agro Chemical hidustries Ltd., 168 AERO , calcium cyanide, 9 Aerojet Fine Chemicals, 215, 229 AEROPHINE , phosphine, 9 AEROTHENE MM , methylene chloride, 9 AFFLAIR , luster pigments, 9 Aflatoxins, 9... 

Cyan-Mthert m. cyanic ester. -Mthyl, n. ethyl cyanide, -bad, n. cyanide bath. -baryum,n. barium cyanide, -benzol, n. cyanobenzene. -bromid, n. cyanogen bromide, -calcium, n. calcium cyanide, -chlorid, n. cyanogen chloride. -doppelsalZt n. double cyanide. 

J.5 Select an acid and a base for a neutralization reaction that results in the formation of (a) potassium bromide (b) zinc nitrite (c) calcium cyanide, Ca(CN)2 (d) potassium phosphate. Write the balanced equation for each reaction. 

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