Crystal structure of the CeNi3In5Sn phase

Ternary systems RE –Ni–In were systematically investigated both for the construction of isothermal sections of phase diagrams and for the detection of isostructural compounds. These systems are characterized by the existence of a large number of compounds in the entire range of concentrations. Compounds with ZrNiAl-, YNiAl 4 -, MgCu 4 Sn- and Mo 2 FeB 2 -type structures exist in almost all RE –Ni–In systems. In addition to others, compounds with the LaNi 3 In 6 -type structure are present in systems with La, Ce, Pr, Nd, and Eu. Crystal structures of the compounds in RE –Ni–In systems are characterized by high coordination of rare earth metal atoms and trigonal or tetragonal prismatic coordination of Ni and In atoms. The purpose of this work is to determine the crystal structure of the CeNi 3 In 5 Sn. Single crystals of the composition Ce 0 . 10 Ni 0 . 30 In 0 . 50 Sn 0 . 10 were grown by heating/cooling procedure of arc-melted alloys in sealed Ta container in high frequency furnace using special thermal mode. The crystal structure was investigated by single crystal X-ray analysis (Stoe IPDS II diffractometer, Mo K α-radiation). The refined composition is confirmed by the results of the EDX analysis (Zeiss EVO MA10 scanning electron microscope). Quantitative and qualitative composition of single crystals according to the results of EDX analysis: 11(1) at. % Ce, 28(1) at. % Ni, 53(1) at. % In, 8(1) at. % Sn is in good agreement with the composition of the prepared sample. The structure was solved and refined using SHELXL–97 package. The CeNi 3 In 5 Sn crystallizes in the LaNi 3 In 6 -type structure, space group Pmmn, a = 0.43497(9), b = 0.75514(15), c = 1.2142(2) nm, R 1 = 0.0409; wR 2 = 0.0412, 809 F 2 values, 37 variables. Coordination polyhedra for cerium atoms are pentagonal prisms with centered side faces and bases (CN = 17). Nickel atoms are located in the center of distorted tetragonal prisms (CN = 8) and trigonal prisms with centered side faces (CN = 9). For the atoms of the statistical mixture of indium and tin, the coordination polyhedra are distorted tetragonal prisms with additional atoms (CN = 12, 13, and 11, respectively). The structure of the CeNi 3 In 5 Sn can be presented as a stack of isolated trigonal prisms and chains of empty octahedra connected through common vertices along the Y axis. The crystal structure of the CeNi 3 In 5 Sn phase has common features with the MgCuAl 2 and YNiAl 4 -type structures. Keywords : Indium, tin, single crystal, crystal structure.