Results for “Ce(CuSi)2”

DOE OSTI2020

Materials Data on Ce(CuSi)2 by Materials Project

CeCu2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ce4+ is bonded to eight equivalent Si4- atoms to form CeSi8 hexagonal bipyramids that share corners with sixteen equivalent CuSi4 tetrahedra, edges with four equivalent CeSi8 hexagonal bipyramids, edges with eight equivalent CuSi4 tetrahedra, and faces with four equivalent CeSi8 hexagonal bipyramids. All Ce–Si bond lengths are 3.12 Å. Cu2+ is bonded to four equivalent Si4- atoms to form CuSi4 tetrahedra that share corners with eight equivalent CeSi8 hexagonal bipyramids, corners with four equivalent CuSi4 tetrahedra, edges with four equivalent CeSi8 hexagonal bipyramids, and edges with four equivalent CuSi4 tetrahedra. All Cu–Si bond lengths are 2.40 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Ce4+, four equivalent Cu2+, and one Si4- atom. The Si–Si bond length is 2.37 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2025

Structural Investigation of Six Quinary Sulfides Synthesized via the Flux-Assisted Boron-Chalcogen Mixture (BCM) Method: Eu 2+ Containing Members of the RE 3 MTQ 7 (M and T = Transition or Main Group Metals, Q = Chalcogens) Family

For this work, a series of six quinary rare-earth sulfides Ce 4+ 1.85 Eu 2+ 1.15 Na 0.30 SiS 7 , Ce 4+ 1.91 Eu 2+ 1.09 K 0.18 SiS 7 , Ce 4+ 1.96 Eu 2+ 1.04 Rb 0.08 SiS 7 , Ce 4+ 1.98 Eu 2+ 1.02 Cs 0.05 SiS 7 , Ce 4+ 1.97 Eu 2+ 1.03 Ag 0.06 SiS 7 , and Ce 4+ 1.50 Eu 2+ 1.50 CuSiS 7 were obtained in an alkali iodide flux using the boron-chalcogen mixture (BCM) method. Single crystal X-ray diffraction was used to determine the structures of the high quality single crystals that were grown; their elemental compositions were confirmed by energy-dispersive spectroscopy (EDS). The compounds crystallize in the hexagonal crystal system in the noncentrosymmetric space group P63. The crystal structure consists of a three-dimensional network composed of mixed cerium and europium bicapped trigonal prisms, isolated SiS4 tetrahedra, and monovalent metals (Na, K, Rb, Cs, Ag, and Cu) located in cavities created by linked Ce/EuS 8 polyhedra. The structures are charge-balanced when Ce and Eu are in their +4 and +2 oxidation states, respectively. The effective magnetic moment of Ce 1.50 4+ Eu 1.50 2+ CuSiS 7 determined from the temperature dependence of the magnetic susceptibility data is consistent with the presence of Ce 4+ and Eu 2+ . Clear correlations between the alkali ion site occupancy, the ionic radius of the alkali cations, and the average bond length of Ce 4+ /Eu 2+ –S, were established. UV–vis diffuse reflectance data were collected for Ce 1.50 4+ Eu 1.50 2+ CuSiS 7 and a band gap of 1.9(1) eV was established.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗