  A ternary compound, MgPtSi, was synthesized by solid-state reaction. An
examination of the compound by powder X-ray diffraction revealed that it
crystallizes in the orthorhombic TiNiSi-type structure with the Pnma space
group. The structure comprises alternately stacked layers of Mg and PtSi
honeycomb network, which is reminiscent of MgB2, and the buckling of the
honeycomb network causes orthorhombic distortion. Electrical and magnetic
studies revealed that MgPtSi exhibited superconductivity with a transition
temperature of 2.5 K. However, its isostructural compounds, namely, MgRhSi and
MgIrSi, were not found to exhibit superconductivity.

Superconductivity