Hybrid Inorganic-Organic Frameworks: Synthesis and Crystal Structures of RbFe(SO4)(C2O4)0.5·H2O and CsM(SO4)(C2O4)0.5·H2O (M = Mn, Fe)

Three new alkali metal transition metal sulfate-oxalates, RbFe(SO 4 )(C 2 O 4 ) 0.5 · H 2 O and Cs M (SO 4 )(C 2 O 4 ) 0.5 · H 2 O ( M = Mn, Fe) were prepared through hydrothermal reactions and characterized by single-crystal X-ray diffraction, solid state UV/Vis/NIR diffuse reflectance spectroscopy, infrared spectra, thermogravimetric analysis, and powder X-ray diffraction. The title compounds all crystallize in the monoclinic space group P 2 1 / c (no. 14) with lattice parameters: a = 7.9193(5), b = 9.4907(6), c = 8.8090(6) Å, β = 95.180(2)°, Z = 4 for RbFe(SO 4 )(C 2 O 4 ) 0.5 · H 2 O; a = 8.0654(11), b = 9.6103(13), c = 9.2189(13) Å, β = 94.564(4)°, Z = 4 for CsMn(SO 4 )(C 2 O 4 ) 0.5 · H 2 O; and a = 7.9377(3), b = 9.5757(4), c = 9.1474(4) Å, β = 96.1040(10)°, Z = 4 for CsFe(SO 4 )(C 2 O 4 ) 0.5 · H 2 O. All compounds exhibit three-dimensional frameworks composed of [ M O 6 ] octahedra, [SO 4 ] 2– tetrahedra, and [C 2 O 4 ] 2– anions. The alkali cations are located in one-dimensional tunnels.