Oxalato Complexes Directly Formed by the Reaction of Interstitial Carbides with Hydrogen Peroxide.

It is well known that ionic carbides such as CaC2, Al4C3 etc. generate hydrocarbons on hydrolysis with water or acids, whereas interstitial carbides such as WC, TiC etc., in which the carbon atoms occupy interstitial positions of the metal lattice, are chemically inert. We found, however, that the latter carbides are dissolved in hydrogen peroxide aqueous solutions, generally to give oxalato complexes of W(VI) etc. This fact means that the carboncarbon bonding is formed by a simple inorganic reaction; for the distance between carbon atoms in such carbides is far longer (about 3 A) than the usual single bonding distance (1.5 A). Oxalic acid can easily be isolated from the complexes as CaC2O4· 2.5H2O. Therefore, this finding provides a new path for the total synthesis of organic compounds.