LaMgX and CeMgX (X = Ga, In, Tl, Pd, Ag, Pt, Au) with ZrNiAl type structure – A systematic view on electronic structure and chemical bonding

Samir F. Matar (1) , Jean Etourneau (1) , Rainer Pöttgen (2)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 Institut für Anorganische und Analytische Chemie

The intermetallic magnesium compounds LaMgX and CeMgX (X = Ga, In, Tl, Pd, Ag, Pt, Au) crystallize with the hexagonal ZrNiAl type structure, space group , with full Mg–X ordering. From density functional theory calculations carried out exemplarily on four representative compounds: LaMgX and CeMgX with X = Ga, Pd, significant differences were traced out as to the magnetism arising only for the Ce series leading to identify CeMgGa as an antiferromagnet in its ground state, in agreement with experiment. The bulk module magnitudes show the trend of harder transition metal based ternaries and the cohesive energies favor the X = Pd compounds versus X = Ga ones. Such features were clarified by examining the properties of chemical bonding which exhibit more directional bonds thanks to the Pd d states. Rationalizing the trends of charge transfers, negatively charged triel and transition element atoms are observed. The resulting chemical pictures assign these compounds as gallides and palladides. 2

Mots clés: A functional alloys (magnetic electrical biomedical); Magnetic properties; Density functional theory; Ab initio calculations

Domaines: Matériaux

Samir F. Matar, Jean Etourneau, Rainer Pöttgen. LaMgX and CeMgX (X = Ga, In, Tl, Pd, Ag, Pt, Au) with ZrNiAl type structure – A systematic view on electronic structure and chemical bonding. Solid State Sciences, 2015, 43, pp.28-34. ⟨10.1016/j.solidstatesciences.2015.03.017⟩. ⟨hal-01138723⟩