Ca2Mg2

Ca2Mg2 is the chemical formula used to denote a calcium–magnesium intermetallic with a 2:2 stoichiometry, which is equivalent to CaMg in reduced form. In most databases and literature, the equiatomic CaMg compound is referred to by the simpler CaMg designation. The Ca–Mg binary system contains several intermetallics, and CaMg represents one equiatomic composition that can occur in ordered crystal structures.

Crystal structure and phase behavior: Intermetallics in the Ca–Mg system can adopt different structures depending on temperature and processing. A commonly reported arrangement for equiatomic CaMg is the CsCl-type (B2) structure, in which calcium and magnesium occupy alternating sublattices. Disorder or other ordered variants may occur under different thermodynamic conditions or after specific heat treatments.

Synthesis and handling: CaMg is typically prepared by combining calcium and magnesium in near-equiatomic ratios under an inert atmosphere, often by arc melting followed by annealing to promote homogeneity. Calcium’s high reactivity with oxygen and moisture requires stringent air-free techniques during handling and processing.

Properties and potential applications: As an intermetallic, CaMg exhibits metallic bonding and properties characteristic of ordered compounds, including relatively high thermal stability and brittleness. Specific properties such as melting point, hardness, and elastic moduli depend on crystal structure and processing history. Research interests in calcium–magnesium intermetallics include hydrogen storage potential and high-temperature materials, though CaMg is not currently a widely adopted commercial material.

See also: Calcium–magnesium phase diagram; intermetallic compounds; hydrogen storage materials.