The invention relates to a method of making alkali metal silicide compositions, and the compositions resulting from the method, comprising mixing an alkali metal with silicon and heating the resulting mixture to a temperature below about 475 °C. The resulting compositions do not react with dry O 2 . Also, the invention relates to sodium silicide compositions having a powder X-ray diffraction pattern comprising at least three peaks with 2Theta angles selected from about 18.2, 28.5, 29.5, 33.7, 41.2, 47.4, and 56.2 and a solid state 23 Na MAS NMR spectra peak at about 18 ppm. Moreover, the invention relates to methods of removing a volatile or flammable substance in a controlled manner. Furthermore, the alkali metal silicide compositions of the invention react with water to produce hydrogen gas.