Mg(3)Pt(2): Anionic Chains in a Eu(3)Ga(2)-Type Structure

[Image: see text] The binary phase Mg(3)Pt(2) was prepared by direct reaction between the elements or by spark-plasma synthesis starting with MgH(2) and PtCl(2). The compound crystallizes in the monoclinic space group C2/c with a = 7.2096(3) Å, b = 7.1912(4) Å, c = 6.8977(3) Å, and β = 106.072(3)° and is isotypic to Eu(3)Ga(2). Analysis of the electron density within the quantum theory of atoms in molecules shows a significant charge transfer from Mg to Pt in agreement with the electronegativity difference. Further study of the chemical bonding with the electron localizability approach reveals the formation of Pt chains stabilized by a complex system of multicenter interactions involving Mg and Pt species. The metallic character of Mg(3)Pt(2) is confirmed by electronic structure calculations and physical measurements.