Dicobalt-EDTA

The basis for the toxicological activity of this substance is the reaction of cobalt ion with cyanide ion to form a relatively nontoxic and stable ion complex. The hexacyanocobaltate ion contains a Co2+ central metal ion with six cyanide ions as ligands. This coordination complex involves six coordinate covalent bonds whereby each cyanide ion supplies a pair of electrons to form each covalent bond with the central cobalt ion. The formation constant for the hexacyanocobaltate ion is even larger than for dicobalt EDTA,3 and thus the cobalt ion preferentially exchanges an EDTA ligand for six cyano ligands ... 

Hydroxocobalamin (Cyanokit) has been the chelator of choice in Europe and Australia, and has been approved for use in the United States since 2007. It works by combining with cyanide to form cyanocobalamin (vitamin B12 Hall and Rumack, 1987). Hydroxocobalamin has been shown to reduce mortality in rats, mice, and beagles and has the advantage of producing neither methemoglobinemia nor hypotension, as sodium nitrite does (Hall and Rumack, 1987 Borron et al., 2006). Dicobalt-EDTA (Kelocyanor) and 4-dimethylaminophenol hydrochloride (4-DMAP) are other chelators available in Europe, Israel, and Australia, but not in the United States (Hillman et al., 1974 Weger, 1990). 

Other than for chelation therapy, in which the ligand is generally administered by slow, intravenous infusion, EDTA has been used in creams and ointments, pharmaceuticals, oils, soaps, bath preparations, cosmetics, and in hair dyes and permanent waving solutions. A novel application of an EDTA chelate is the use of the dicobalt chelate (dicobalt edetate) as an antidote in cyanide poisoning the CN ion forms a strong ionic complex with the Co ions in the chelate to form a relatively non-toxic and readily excretable species. 

Dicobalt ethylene diamine tetraacetic acid (EDTA) (Kelocyanor/ IV Risk Cardiac Dysrhythmias angina, death Europe commercial USA Experimental Post exposure N/A... 

EDTA Ethylene diamine tetraacetic acid (dicobalt)... 

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