Synthesis, Structural Characterization, and Ab initio Study of Cu5In2Sb2: A New B8-Related Structure Type

C. MÜLLER; S. LIDIN; S. RAMOS DE DEBIAGGI; C. DELUQUE TORO; A. FERNÁNDEZ GUILLERMET

INORGANIC CHEMISTRY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2012 vol. 51 p. 10787 - 10792

0020-1669

A new ternary orthorhombiccompound with the formula Cu5-dIn2+xSb2-x, crystallizing in the symmetry group Cmc21 with 36 atoms per unit cell (a=10.1813(4) Å, b=8.4562(4)Å, c=7.3774(2) Å, Z=4) has been synthesized by conventional high temperaturemethods. The structure is based on the B8 archetype (NiAs/Ni2In) andfeatures In/Sb ordering as well as ordering of interstitial Cu. Details of theexperimental study and the structural parameters of this compound are reportedin the first part of the work. In the second part, ab initiocalculations based on the density-functional theory (DFT) and the projectoraugmented-wave method (PAW) are used to characterize the structural,thermodynamic and phase-stability properties of the new ternaryphase. The present calculations includethe lattice parameters, molar volume, bulk modulus and its pressure derivative,the energy of formation from the elements and the electronic density of states.Moreover, the present ab initiomethod is used to investigate the thermodynamic properties of the anti-structureCu5Sb2In2 compound obtained by exchanging the In and Sb Wyckoffsymmetric positions.