Gold cyanidationGold cyanidation (also known as the cyanide process or the MacArthur–Forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex. It is the most commonly used leaching process for gold extraction. Cyanidation is also widely used in the extraction of silver, usually after froth flotation. Production of reagents for mineral processing to recover gold represents more than 70% of cyanide consumption globally.
MethylcobalaminMethylcobalamin (mecobalamin, MeCbl, or MeB_12) is a cobalamin, a form of vitamin B_12. It differs from cyanocobalamin in that the cyano group at the cobalt is replaced with a methyl group. Methylcobalamin features an octahedral cobalt(III) centre and can be obtained as bright red crystals. From the perspective of coordination chemistry, methylcobalamin is notable as a rare example of a compound that contains metal–alkyl bonds. Nickel–methyl intermediates have been proposed for the final step of methanogenesis.
CyanohydrinIn organic chemistry, a cyanohydrin or hydroxynitrile is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is , where R is H, alkyl, or aryl. Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids.
Photographic processingPhotographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive . Photographic processing transforms the into a visible image, makes this permanent and renders it insensitive to light. All processes based upon the gelatin silver process are similar, regardless of the film or paper's manufacturer. Exceptional variations include instant films such as those made by Polaroid and thermally developed films.
EthylenediamineEthylenediamine (abbreviated as en when a ligand) is the organic compound with the formula C2H4(NH2)2. This colorless liquid with an ammonia-like odor is a basic amine. It is a widely used building block in chemical synthesis, with approximately 500,000 tonnes produced in 1998. Ethylenediamine is the first member of the so-called polyethylene amines. Ethylenediamine is produced industrially by treating 1,2-dichloroethane with ammonia under pressure at 180 °C in an aqueous medium: In this reaction hydrogen chloride is generated, which forms a salt with the amine.
