Tellurium mercuric cyanide

Irioxide, platinum, silver, potassium chlorate, potassium ferricyanide, potassium mercuric cyanide, silver chloride, stibine, tellurium halides, tellurium hydropentachloride, tetramethy-lammonium amide, trimethylammonium amide, trioxygen difluoride, vinyl acetate. Violent polymerization with ethylene oxide. Attacks some coatings, plastics, and rubber. Attacks copper, brass, bronze, aluminum, steel, and their alloys. 

If pulverized specimens of these elements are mixed with an excess of mercuric cyanide and then heated to 130-180° C, the resulting vapors will give the blue coloration with the hydrogen cyanide reagent described on page 347. The mechanism of this pyrolytic reaction has not been elucidated as yet it may be carried out within the technique of spot test analysis. Probably the reaction is due to the production of volatile cyanides of selenium, tellurium etc. to a sufScient extent and these vapors react in a similar way as hydrogen cyanide toward the reagent. 

Procedure. A small quantity of the sample is placed in a micro test tube along with 20-30 mg solid mercuric cyanide. The tube is then immersed in a glycerol bath which has been preheated to 130 C and the open end of the tube is covered with a disk of filter paper that has been moistened with a drop of the Cu ethyl acetoacetate and tetrabase reagent. The presence of sulfur, selenium or tellurium is indicated by the development of a blue color on the paper within 3 minutes. 

A test for elementary sulfur, selenium and tellurium is described on page 91. It is based on p5u-olysis of the sample with mercuric cyanide the resulting vapors give the color reaction of HCN. The reaction can also be used for the detection of mercuric cyanide. 

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