Note 31 — Chapter IX · COMPOUNDS OF CARBON WITH OXYGEN AND NITROGEN

The molecule of metallic potassium (Scott, 1887), like that of mercury, contains only one atom, and it is probably in virtue of this that the molecules CO and K combine together. But as in the majority of cases potassium acts as a univalent radicle, the polymeride K2C2O2 is formed, and probably K10C10O10, because products containing C10 are formed by the action of hydrochloric acid. The black mass formed by the combination of carbonic oxide with potassium explodes with great ease, and oxidises in the air. Although Brodie, Lerch, and Joannis (who obtained it in 1873 in a colourless form by means of NH3K, described in Chapter VI., Note 14) have greatly extended our knowledge of this compound, much still remains unexplained. It probably exists in various polymeric and isomeric forms, having the composition (KCO)n and (NaCO)n.