Silver nitrate, darkening

Silver iodomercurate [36011-71-9] Ag2HgI, is a bright yellow compound and is prepared similarly to the cuprous salt where silver nitrate is the precipitant. The silver salt, which darkens reversibly at 50°C, is used for the same appHcation as cuprous iodomercurate. 

Silver nitrate Mercury (II) chloride Hypophosphites, H2P02 White precipitate of silver hypophosphite White precipitate of calomel in cold solution, which darkens upon... 

Barium chloride Strontium chloride Silver nitrate White precipitate of the respective sulfite, the precipitate being soluble in dilute hydrochloric acid At first no change upon addition of more reagent, white crystalline precipitate at silver sulfite forms, which darkens to metallic silver upon heating... 

Naphthol. Prisms, mp, 96°C phenolic odor disagreeable, burning taste bp, 288°C. Sublimable volatile with steam. Darkens in light reduces ammoniacal silver nitrate.1... 

Naphthol. Crystals, mp, 121-123°C bp, 285-2860C. Flash point, 161°C. Slight phenolic odor. Darkens with age on exposure to light. Sublimes when heated, distillable in vacuo volatile with vapors of alcohol or water reduces ammoniacal silver nitrate.1... 

The purified oxide should be devoid of any alliaceous odour or odour of phosphine, and should not reduce a boiling solution of mercuric chloride. When dissolved in water and the solution neutralised with alkali (to methyl orange) it should give a white precipitate with silver nitrate which should not darken after boiling for five minutes. 

Silver carbonyl ferrocyanide, Ag3[Fe(CN)5CO], is obtained as a white curdy precipitate on addition of the potassium salt to silver nitrate solution in the presence of acetic acid.4 It rapidly darkens even when protected from the light. Insoluble in boiling acetic acid, it is slightly soluble in dilute mineral acids evolving hydrogen cyanide. Potassium hydroxide liberates silver oxide, potassium carbonyl ferrocyanide being simultaneously produced. 

Uranous Hydroxide.—The addition of alkali to a solution of a uranous salt produces a reddish-brown gelatinous precipitate, which darkens in colour on boiling the solution. If dried in vacuo it becomes black and has the composition UOg.HgO. This rapidly oxidises in the air and readily dissolves in dilute acids, forming uranous salts. It acts upon a neutral solution of silver nitrate, first precipitating silver oxide and forming a green solution which, however, soon turns yellow, and the oxide is reduced to metallic silver as the uranyl salt forms in solution, thus ... 

Silver nitrate, a white ppt, soluble in HNO, and in NH,HO. The ppt. does not darken when the fluid is boiled, but, when dried and heated on platinum foil, it explodea... 

Prisms, mp 96 . Phenolic odor disagreeable, burning taste, bp 288 bp 184. dj -7 1.0954, uv max 297, 310, 324 nm. Sublimable volatile with steam. Darkens in light reduces ammonia cal silver nitrate. Slightly sol in water, freely in alcohol, benzene, chloroform, ether, alkali hydroxide solns. Protect from light LDM orally in rats 2.59 g/kg, H, F. Smyth et al. Am. Ind. Myg. Assoc. J. 23, 95 (1962). 

White powder darkens on exposure to light, d 5.56 mp 455 bp 1550. Soly in water (23 ) 1.93 mg/1 hydrochloric acid increases its soly. Sol in 250 parts of coned HC1, in 13 parts of 10% ammonia more sol in stronger ammonia and also at higher temps. Sol in solns of alkali cyanides, thiosulfates, ammonium carbonates appreciably sol in coned aq solns of ammonium chloride mercuric nitrate, and silver nitrate. The freshly pptd chloride dissolves more readily than tha dried precipitate. Insol in alcohol, or dil acida. Protect from light. 

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. 

Yellow, odorless powder darkens in light, d 6.37. mp 849°. Reduced by hydrogen. Soluble in 15,500 parts water, the soly in water is decreased by presence of silver nitrate slightly sol in dil acetic acid freely sol in dil nitric acid, in ammonia, ammonium carbonate, also in alkali cyanides and thiosulfates. Protect from tight. 

Analytical Characters.—(1.) In neutral or alkaline solution a white ppt. with a solution of a Ca salt. (2.) Silver nitrate, a white ppt., soluble in HNOa and in NHiHO. The ppt. does not darken when the fluid is boiled, but, when dried and heated on platinum foil, it explodes. (3.) Lead acetate, in solutions not too dilute, a white ppt., soluble in HNOs, insoluble in acetic acid. 

Figure 3.15 Johan Heinrich Schulz (1687-1744), who discovered the darkening of silver nitrate crystals under light irradiation. (Published with permission from the Deutsches Museum, Munich.)...

Toxicity The acute toxicity of silver metal is low. The acute toxicity of soluble silver compounds depends on the counterion and must be evaluated case by case. For example, silver nitrate is strongly corrosive and can cause burns and permanent damage to the eyes and skin. Chronic exposure to silver or silver salts can cause a local or generalized darkening of the mucous membranes, skin, and eyes known as argyria. The other chronic effects of silver compounds must be evaluated individually. 

Silica gel impregnated with silver nitrate (usually 5-10%) is also a useful adsorbent for some functional groups. The silver cation selectively binds to unsaturated sites via a sUver-ion tt complex. Traces of alkenes are easily removed from saturated reaction products by chromatography with this system (see Experiment [12]). This adsorbent, however, must be protected from light until used, or it will quickly darken and become ineffective. 

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