title: Solvothermal synthesis, structure and physical properties of Cs[Cr(en)2MSe4] (M = Ge, Sn) with [MSe4](4-) tetrahedra as chelating ligand.
abstract: Two chromium chalcogenide Cs[Cr(en)2GeSe4] () and Cs[Cr(en)2SnSe4] () have been synthesized by a solvothermal method. Both compounds crystallize in the monoclinic space group P21/n. The structures of the two compounds are characterized by isolated [Cr(en)2MSe4](-) clusters separated by Cs(+) ions. The optical properties of the two compounds were measured which indicate a similar band gap of 1.58 eV. DFT calculations demonstrated that the valance band maximum (VBM) consist of Cr 3d orbitals and Se 4p orbitals while the conductive band minimum (CBM) are composed of Cr 3d orbitals for both compounds, which explains their similar optical band gap energies. Both compounds possess paramagnetic behaviors with the effective magnetic moment of 3.97μB for Cs[Cr(en)2GeSe4] and 3.91μB for Cs[Cr(en)2SnSe4], respectively. Field-dependent magnetization measurements demonstrated their potential as magnetocaloric materials, with the magnetic entropy change of 11.6 J (kg K)(-1) for Cs[Cr(en)2GeSe4], and 14.2 J (kg K)(-1) for Cs[Cr(en)2SnSe4].
authors.affiliation: Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, P. R. China.
authors.forename: Yingqi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. huangfq@pku.edu.cn.
authors.forename: Ruiqi
authors.initials: R
authors.lastname: Wang
authors.affiliation: Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. huangfq@pku.edu.cn.
authors.forename: Qinglong
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. huangfq@pku.edu.cn.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Lai
authors.affiliation: Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. huangfq@pku.edu.cn.
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department CAS Key Laboratory of Materials for Energy Conversion Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, P.R. China.
authors.forename: Haijie
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, USA. czheng@niu.edu.
authors.forename: Chong
authors.initials: C
authors.lastname: Zheng
authors.affiliation: Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. huangfq@pku.edu.cn.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Lin
authors.affiliation: Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. huangfq@pku.edu.cn and Department CAS Key Laboratory of Materials for Energy Conversion Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, P.R. China.
authors.forename: Fuqiang
authors.initials: F
authors.lastname: Huang