Sparingly soluble compounds sulfides, 221

Partial reduction of aromatic polynitro compounds leads to nitro amines. The most successful reagents are the alkali metal or ammonium sulfides in aqueous alcoholIn some instances, sodium bicarbonate combined with sodium sulfide gives better results because of the formation of sodium hydrosulfide, which is believed to be the main reducing agent. Also, aqueous methanol is preferred to aqueous ethanol. Nitro compounds that are sparingly soluble in alcohol solutions may be reduced by hydrogen sulfide in pyridine solution. ... 

PHYSICAL PROPERTIES most inorganic mercury compounds are white powders or crystals mercuric sulfide (cinnabar) is red and turns black when exposed to light insoluble in hydrochloric or similar acids soluble in nitric acid and hot concentrated sulfuric acid water soluble salts include mercuric chlorate, cyanide, chloride and aeetate oxides, sulfates and most other common salts, including mercurous chloride, are sparingly soluble or deeomposed in water appearances vary from eolorless crystals to yellow, red (oxide, sulfide, iodide), and brown or black (sulfide) MP (-39°C, -38°F) BP (357 C, 674 F) DN (13.534 gW at 25°C) SG (13.5) VD (not applicable) VP (0.0012 mitiHg at 20°C). 

Mercurous and mercuric chloride, known respectively as calomel and corrosive sublimate, are two of the most important salts of mercury. Other halogenated mercury salts include mercurous bromide, Hg2Br2, a yellowish-white powder insoluble in water mercuric bromide, HgBr2, comprised of white crystals sparingly soluble in cold water but readily soluble in hot water mercurous iodide, Hg2l2, a yellowish-green powder and mercuric iodide, which exists in two crystalline forms. Other mercuric and mercurous compounds include nitrates, nitrites, sulfides, sulfates, phosphides, phosphates, and ammonium salts. 

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