Crystal structure and properties of the new ternary compound Mg21Ga5Hg3

The crystal structure of a new ternary compound Mg21Ga5Hg3 has been studied using X-ray powder diffraction data by Rietveld method. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDXS) was used for sample composition examination. The compound crystallizes in the Ge8Pd21 structure type (space group I41/a, a = 1.45391(5) nm, c = 1.15955(4) nm, Z = 4). All interatomic distances indicate metallic type bonding. The average thermal expansion coefficients αa, αc and αV of Mg21Ga5Hg3 are 2.60 × 10−5 K−1, 2.02 × 10−5 K−1, and 7.25 × 10−5 K−1, respectively. Electrical resistivity of Mg21Ga5Hg3 was measured between 5 and 300 K.