Mg2Si

Mg2Si is the inorganic compound magnesium silicide, an intermetallic with a 2:1 magnesium-to-silicon ratio. It crystallizes in a cubic antifluorite-type structure in which silicon forms an fcc lattice and magnesium atoms occupy the tetrahedral sites. This arrangement gives Mg2Si characteristic electronic and bonding properties distinct from pure metals and covalent silicon.

Synthesis and handling typically involve high-temperature solid-state reactions between elemental magnesium and silicon under inert atmosphere. It can also be prepared by other routes such as mechanical milling or reactions involving magnesium hydride and silicon. Because Mg2Si reacts with water and with acids to release hydrogen-containing silicon species (for example silane, SiH4), handling and storage generally require inert conditions to prevent hydrolysis.

Electronic and thermoelectric properties are central to Mg2Si. It is a narrow-bandgap semiconductor, with an indirect bandgap around 0.6–0.7 eV, and its electrical conduction can be tuned by doping. As a result, doped Mg2Si and related solid solutions have been studied extensively for thermoelectric applications, particularly at mid- to high temperatures, where favorable combinations of electrical conductivity and reduced thermal conductivity can yield competitive performance.

Applications and research focus on Mg2Si largely concern thermoelectric materials, including doped and nanostructured forms, as well as solid solutions such as Mg2Si1−xGex for bandgap engineering. The compound remains of interest for fundamental studies of intermetallic semiconductors and for potential use in energy conversion devices, while requiring careful handling due to its reactivity with water and acids.