Reducing agents mercury hydrides

MERCURY(n) NITRATE (10045-94-0, anhydrous 7783-34-8, monohydrate) Hg(N03)2 H,0 Noncombustible solid. Light sensitive. A powerful oxidizer accelerates the burning of combustible materials. Violent reaction, or may form explosive materials, with reducing agents, including hydrides, nitrides, phosphorus, stannous chloride, and sulfides alkyl esters (forms explosive alkyl nitrates) combustible materials (especially if finely divided), phosphinic acid, hypophosphoric acid, metal powders petroleiun hydrocarbons. Forms heat- and/or shock-sensitive compounds with acetylene (forms explosive mercmy acetylide), ethanol and other alcohols (may form explosive mercury fulminates), ferrocene, isobutene, phosphine gas (forms heat- and shock-sensitive precipitate) potassiiun cyanide, sulfur. Incompatible with strong acids, acetic anhydride, ammonia, ammonium hexacyanofenate(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. 

It is a colourless gas which decomposes on heating above 420 K to give metallic tin, often deposited as a mirror, and hydrogen. It is a reducing agent and will reduce silver ions to silver and mercury(II) ions to mercury. SnSn bonding is unknown in hydrides but does exist in alkyl and aryl compounds, for example (CH3)3Sn-Sn(CH3)3. 

Atomic hydrogen is a powerful reducing agent, even at room temperature. For example, it reacts with the oxides and chlorides of many metals, including silver, copper, lead, bismuth, and mercury, to produce the free metals. It reduces some salts, such as nitrates, nitrites, and cyanides of sodium and potassium, to the metallic state. It reacts with a number of elements, both metals and nonmetals, to yield hydrides such as NH3, NaH, KH, and PH3. Sulfur forms a number of hydrides the simplest is H2S. Combining with oxygen, atomic... 

The present review considers recent advances in mercury-hydrogen interchange by protonolysis and reducing agents, and especially metal hydride demercuration. 

A number of chemicals are used as reducing agents. The most common chemicals used for reduction of chromium are sulfur dioxide, sodium metabisulfite, sodium bisulfite, and ferrous salts. Other reducing agents used or which can be potentially used for water and wastewater treatment include sodium borohydride to reduce ionic mercury to metallic mercury and alkali metal hydride to alter the chemical form of lead so that it can be precipitated and also to recover silver. The common chemicals used as reducing agents are discussed on the following sections. 

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