Cadmium chloride, anhydrous

Organocadmiura compounds may be prepared by the action of anhydrous cadmium chloride upon the corresponding Grignard reagents, for example ... 

Propiophenone. Prepare a solution of diphenyl-cadmium in 110 ml. of dry benzene using 4 9 g. of magnesium, 32 4 g. of bromobenzene and 19 5 g. of anhydrous cadmium chloride. Cool the solution to 10°, and add during 3 minutes a solution of 14 -8 g. of propionyl chloride (b.p. 78-79°) in 30 ml. of dry benzene use external coohng with an ice bath to prevent the temperature from rising above 40°. Stir the mixture for 2 hours at 25-35°. Work up the product as detailed above except that 6 per cent, sodium carbonate solution should replace the saturated sodium bicarbonate solution. The yield of propiophenone, b.p. 100-102°/16 mm., is 17 6 g. 

Di-n-butylcadmium was prepared by the rapid addition of cadmium chloride (50.4 g, 0.275 mol) to a cooled solution of n-butylmagnesium bromide formed from magnesium (12.15 g, 0.50 mol) and n-butyl bromide (75.4 g, 0.55 mol) in anhydrous diethyl ether (550 ml). Following the addition, the reaction mixture was stirred at 0°C for 2 h. The di-n-butylcadmium reaction mixture, including the precipitate, was then added to a stirred solution of phosphorus trichloride (85.9 g,... 

The solution is evaporated and crystallized to yield a hydrated salt. The hydrated salt yields anhydrous cadmium chloride upon heating under hydrogen chloride or when refluxed with thionyl chloride. 

Hexammino-cadmium Chloride, [Cd(NH3)6]Cl2.—When anhydrous cadmium chloride is exposed to an atmosphere of dry ammonia the gas is rapidly absorbed, the mass increases in bulk, heat is developed, and the hexammine produced. It has also been prepared by exposing anhydrous cadmium chloride to dry gaseous ammonia for two hours in a tube cooled to very low temperature. A layer of liquid ammonia forms on the surface of the solid, and the tube is sealed and kept for some time at —70° C. On opening and allowing the temperature to rise to —30° C. to remove the condensed ammonia a residue of the hexammino-salt is left.2... 

Cadmium Metaniobate.—The anhydrous salt, Cd0.Nb205, is obtained by fusing potassium niobate with cadmium chloride. It forms yellowish-brown, glistening crystals, the density of which is 5-93.4 The hydrated salt Cd0.Nb20s.3 H20 is thrown down as a pale yellow precipitate on adding a solution of a cadmium salt to sodium metaniobate.8... 

Detection and Determination of the Pyridine Bases. (A) Qi ai.itativK lV.sf. 1. From 5 to f> c.c. of the alcoholic distillate, which should have- a strength of at least Hjj% (by vol.), is shaken with a- c.c. of a 5% solution of anhydrous cadmium chloride, in alcohol. In presence of pyridine a white precipitate forms either immediately or after some time. 

Cadmium compounds are very toxic and a suitable face mask should be worn to prevent inhalation of dust. Anhydrous cadmium chloride can be obtained from the commercially available hydrated compound in the following way dry the hydrate to constant weight at 110°C grind finely, dry again for 2-3 hours at 110°C and then place in a screw-capped bottle and keep in a desiccator over calcium chloride. The use of anhydrous cadmium chloride in synthesis is described in Expts 5.94 and 6.126. 

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