Oxidation of M4Si4 (M = Na, K) to clathrates by HCl or H2O

Article abstract of DOI:10.1021/ja0705691

The synthesis of clathrate-II germanium □₂₄Ge₁₃₆ in an ionic liquid was recently discovered.¹ The key step in this process, the controlled oxidation of reactive precursor phases by a protic acid, was successfully applied to silicides M₄Si₄ (M = Na, K). Through this method, clathrate-I compounds of composition M_8-xSi₄₆ were obtained as crystalline products. The synthetic method demonstrates a mild oxidative route to a large class of metastable intermetallic compounds. Copyright