Metal carbonyl 18-electron complexes is sometimes catalysed by catalytic amounts of oxidants, via electron-transfer. Metal carbonyls react with reducing agents such as metallic sodium or sodium amalgam to give carbonylmetalate (or carbonylate) anions: For iron pentacarbonyl, one obtains the tetracarbonylferrate with loss of CO: Mercury can insert into the metal-metal bonds of some polynuclear metal carbonyls: The CO ligand is often susceptible to attack by nucleophiles. For example, trimethylamine oxide and bistrimethylsilylamide convert CO ligands to CO and CN, respectively. In the "Hieber base reaction", hydroxide ion attacks the CO ligand to give a metallacarboxylic acid, followed by the release of carbon
Mercury(II) thiocyanate from dark graphite grey to light tan in color with the inside generally much darker than the outside. The reaction has several stages as follows: Igniting mercury thiocyanate causes it to form an insoluble brown mass that is primarily carbon nitride, CN. Mercury sulphide and carbon disulphide are also produced. 2Hg(SCN) → 2HgS + CS + CN Carbon disulphide combusts to carbon dioxide and sulphur dioxide: CS + 3O → CO + 2SO The heated CN partially breaks down to form nitrogen gas and cyanogen: 2CN → 3(CN) + N Mercury sulphide reacts with oxygen to form mercury vapour and