Mercuric cyanide thiocyanate

Silver and mercuric cyanides form thiocyanates, but considerable amounts of sulphides are also precipitated. 

Mercuric Selenocyanate, Hg(CNSe)a, forms a crystalline mass when mercuric acetate is treated with potassium selenocyanate. The crystalline mass consists of white needles which are slightly soluble in cold water but readily soluble in alkali cyanide, thiocyanate and selenocyanate solutions. Mercuric selenocyanate turns brown in air and is decomposed by heat.4... 

Diphenylacetonitrile has been prepared by the dehydration of diphenylacetamide, " by the reaction of diphenylbromomethane and mercuric cyanide, by the reaction of diphenylacetic acid and lead thiocyanate, and by the removal of ammonia from diphenyl-acetamidine. The present method is a modification of that of Hoch.ii... 

Designation of Hazardous Substances- List of hazardous substances, Table 116.4 (mercuric cyanide, mercuric nitrate, mercuric sulfate, mercuric thiocyanate, mercurous nitrate) Yes 40 CFR 116.4 EPA 1978a... 

Merchloroethamine Mercuric acetate Mercuric arsenate Mercuric chloride Mercuric cyanide Mercuric sulfate Mercuric sulfide Mercuric thiocyanate Mercurous nitrate Mercury... 

The formation of (II) provides a quite selective spot test for palladium. Gold must be removed prior to the test because it will cause the development of a deep ruby red in the spot plate test and a diffused violet spot on the paper, apparently due to the reduction of the gold ions to the colloidal metal. Interference may also arise from 0s04 , Os+, Ru+, and RuCle ions because they have distinct self-colors. Mercurous ion causes partial interference by the reduction of part of the palladium to the elementary state, but a positive response can still be seen. It is possible to detect I part of palladium in the presence of 200 parts of platinum or 100 parts of rhodium. Less favorable ratios should be avoided because of the color of these salts. No interference is caused by mercuric and iridic chloride, but free ammonia, ammonium ions, stannous, cyanide, thiocyanate, fluoride, oxalate, and tetraborate ions do interfere. Lead, silver, ferrous, ferric, stannic, cobaltous, nickel, cupric, nitrite, sulfate, chloride, and bromide ions do not interfere. 

L. Berczeller has shown that the presence of acids, chlorides, bromides, iodides, thiocyanates, and morphine accelerate the reaction while the presence of tartrates, sulphates, oxalates, carbonates, mercuric chloride, bromide, iodide, and cyanide, most alkaloids, colloids, proteins, etc., inhibit the reaction. Hydrocyanic acid, unlike other acids, also inhibits the reaction. A. Skrabal has shown that Landolt s reaction has a temp, coeff. greater than unity, so that the velocity of the reaction increases with a rise of temp. but if the system contains an excess of sodium sulphate, the temp, coeff. is less than unity, and the velocity of the reaction decreases with a rise of temp. 

Thirty-five grams of mercuric acetate and 25 g. of ammonium thiocyanate are dissolved in 100 ml. of hot glacial acetic acid. A steady stream of hydrogen sulfide is conducted into the hot solution until precipitation is complete. Then the acetic acid is slowly evaporated. (Caution Hydrogen cyanide gas is evolved.) The black precipitate that first appears slowly changes to the red modification as the acid boils away. Until this change is... 

MERCURIC THIOCYANATE (592-85-8) Hg(SCN)i Moderately unstable solid. Possible violent reaction with strong oxidizers strong acids organic peroxides, peroxides and hydroperoxides potassium chlorate potassium iodate, silver nitrate, sodium chlorate, nitric acid. Incompatible with ammonia, chlorates, hydrozoic acid, methyl isocyanoacetate, nitrates, nitrites, perchlorates, sodium peroxyborate, trinitrobenzoic acid, urea nitrate. When heated, this material swells to many times its original bulk. Attacks aluminum in the presence of moisture. Decomposes above 329°F/165°C, releasing toxic mercury and cyanide fumes, and sulfur and nitrogen oxides. On small fires, use dry chemical powder (such as Purple-K-Powder), alcohol-resistant foam, or COj extinguishers. MERCURIC (Spanish) (7439-97-6) see mercury. 

MERCURIC NITRATE (10045-94-0) A powerful oxidizer. Violent reaction with reducing agents, combustibles, phosphinic acid, hypophosphoric acid, petroleum hydrocarbons. Forms heat- and/or shock-sensitive compounds with acetylene (forms mercury acetylide), ethanol (forms mercury fulminate), ferrocene, isobutene, phosphine, potassium cyanide, sulfur. Incompatible with strong acids, acetic anhydride, ammonia, ammonium hexacyanofer-rate(II), organic azides, citric acid, hydrazinium perchlorate, isopropyl chlorocarbonate, nitrosyl perchlorate, sodium thiosulfate, sulfamic acid, thiocyanates, hydrozoic acid, methyl isocyanoacetate, sodium peroxyborate, trinitrobenzoic acid, urea nitrate. Aqueous solution corrodes metals. 

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. 

This exercise is particularly interesting because it permits us to specify the conditions that must be respected in order to carry out the titration of chloride, bromide, thiocyanate, and cyanide ions with a mercuric salt according to Votocek-Dubsky s method (see Chap. 27). The titrant solution is a mercuric nitrate (or sulfate) solution in which the precipitation of HgO resulting from the hydrolysis of Hg2+ is precluded by addition of nitric acid. 

Votocek-Dubsky s method is based on the property exhibited by some mercuric salts to be very poorly ionized in solution because they actually are complexes. This property is shared by halide, cyanide, and thiocyanate ions. Oxygenated salts, however, are normally ionized (nitrate, sulfate). From another standpoint, sodium nitroprusside forms a white precipitate of mercuric nitroprusside with Hg + ions, that is, with oxygenated mercuric salts but not with halides or parent compounds because of their property of being complexes. The principle of Votocek s method results from these considerations (see Fig. 27.1). 

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