Aurous chloride

Ammino - aur ous Chlorides.—Aurous chloride unites with ammonia, forming dodecamrnino-aurous chloride, AuC1.12NH3 triammino-... 

When aurous chloride is mixed with liquid ammonia at a temperature below —28° C. the salt absorbs ammonia, yielding an addition compound containing twelve molecules of ammonia, AuC1.12NH3. This substance is stable only below —28° C., and when the temperature rises to +20° C. nine molecules of ammonia are eliminated, forming the compound triammino-aurous chloride, [Au(NHs)3]C1.1... 

Prepared in the above manner, triammino-aurous chloride is a white powder which is comparatively stable. It may be heated to 180° C. without decomposition, but above that temperature it dissociates, yielding gold and ammonium chloride. It is decomposed by water, and dilute acids cause it to lose ammonia with formation of the unstable monammino-aurous chloride. When treated with potassium hydroxide ammonia is evolved and a brown explosive substance formed. 

Diammino-aurous Chloride, [Au(NH3)3]C1, is formed by saturating dry aurous chloride with ammonia gas at ordinary temperature. The diammine is a white voluminous powder, and has dissociation temperature 113-5° C.2... 

Monammino-aurous Chloride, [Au(NIIs)]Cl.—When aurous chloride is dissolved in an aqueous solution of ammonia and the mixture acidified with hydrochloric acid a white crystalline precipitate separates the precipitate is unstable and cannot therefore be completely dried.3... 

Monammino-aurous chloride is a white crystalline powder, sparingly soluble in water, soluble in an aqueous solution of ammonia, and precipitated by the addition of hydrochloric acid. It is unstable in the dry state, and decomposes completely on heating between 150° and 200° C. Aurous bromide and aurous iodide also unite with ammonia. The former yields only one ammino-derivative, the diammine, [Au(NII3)g]Br, and the latter two ammino-derivatives, namely, heAmmino-aurous iodide, [Au(NH3)6]I, and monammino-aurous iodide, [Au(NH3)]I. 

Rose has found that with an electrolyte containing 29 per cent, of free hydrochloric acid, and with a current-density of 5000 amperes per square m tre of anode surface, no chlorine is evolved, even with an anode containing 20 per cent, of silver. The heavy current causes the silver chloride to separate from the anode, and as aurous chloride is not allowed to form, deposition of gold in the anode-slime is prevented. 

Aurous chloride, AuCl.—Partial elimination of chlorine from auric chloride by means of heat yields aurous chloride, but it is difficult to... 

The chloride2 is a yellowish-white substance, soluble in aqueous alkali-metal chlorides 3 with formation of complex anions, the solutions soon decomposing with precipitation of metallic gold and the formation of complex auric derivatives. The transformation is more rapid in bromide solutions. At 110° to 120° C. aurous chloride and excess of phosphorus trichloride combine to form a double compound of the formula AuCl,PCl3, colourless prisms insoluble in water.4... 

Aurous bromide, AuBr.—When auric bromide is heated, bromine is evolved, and aurous bromide left as a green mass.5 It is also formed by heating auribromic acid, HAuBr4, the auric bromide formed decomposing at 115° C. Above this temperature it is decomposed into gold and bromine, and reacts with water like aurous chloride. Aqueous hydro-bromic acid converts it into gold and auribromic acid, HAuBr4 ... 

Subsequent investigation of the corresponding complex with aurous chloride 307) placed the point of coordination at the norbornene side. Recent investigations 584) of the CuCl-catalyzed photochemical dimerization of norbornene and cxo icyclopentadiene have established that dimerization occurs similarly with both molecules, i.e., through the double bonds of the norbornene rings. Since it is considered that the reaction intermediate involves complexing of the olefin molecules at the Cu(I) atom it is almost a certainty that the coordination of dicyclo-pentadiene to Cu(I) is through the norbornene unsaturation. 

Potassium dichromate, KoCroOy Aurous chloride, AuCl Nitrous acid, HNOo Ammonium nitrite, NH4NO2 Sodium oxide, Na20 Peroxysulfate ion, SO- —... 

Hydrogen aurichloride can be obtained as a yellotc crystalline substance, which forms salts with bases. When heated it forms auric chloride, AuClg, and then an aurous auric chloride, Au.,Cl, and then aurous chloride, AuCl. On further heating all the chlorine is lost, and pure gold remains. 

Metallurgy of gold. Aurous chloride, aurous bromide, aurous iodide, potassium aurous cyanide, auric chloride, hydrogen aurichloride. 

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