| There are two classes of percarbonates, one obtained by the electrolytic oxidation of carbonates, the other by the combination of hydrogen peroxide with carbonates, or of carbon dioxide with peroxides. Alkali perthiocarbonates, e.g. Na2CS4, exist corresponding to the latter kind of percarbonates. They are formed by the combination of carbon disulphide with alkali disulphides, with which this substance unites more readily than with the monosulphides, and also by the direct combination of thiocarbonates with sulphur. There is no analogy to this latter method of preparation in the case of percarbonate; and this fact illustrates the superior chain-forming power of sulphur as compared with oxygen atoms. |