Synthesis,Crystal Structures And Properties Of Transition Metal Sulfates

In the thesis,our research are mainly the synthesis,crystal sturctures、magnetic and electrochemical properties of transition metal sulfates complexes.New transition metal sulfates complexes were synthesized through dissolution and precipitation route and hydrothermal method,alkali metal sodium transition metal sulfates Na₆Fe（SO₄）₄·2H₂O（1）、Na₆Co（SO₄）₄·2H₂O（2）、Na₆Ni（SO₄）₄·2H₂O（3）;alkali metal transition metal sulfate-oxalates K₂Mn（SO₄）（C₂O₄）（4）、Rb₂Mn（SO₄）（C₂O₄）·2H₂O（5）、Rb Fe（SO₄）（C₂O₄）_0.5·H₂O（6）、Cs Mn（SO₄）（C₂O₄）_0.5·H₂O（7）and Cs Fe（SO₄）（C₂O₄）_0.5·H₂O（8）.The compounds single crystal data were gathered on X-ray single crystal diffraction with Bruker D8 Quest CMOS,and the data were solved by SHELXL-2014 software.The compounds were characterized by powder X-ray diffraction,FT-IR spectra,solid state UV-vis-NIR diffuse reflectance spectroscopy,thermal gravity analysis（TGA）and magnetism measuring instrument.The main research contents are as follow:1.Alkali metal transition metal sulfates:Na₆Fe（SO₄）₄·2H₂O（1）、Na₆Co（SO₄）₄·2H₂O（2）、Na₆Ni（SO₄）₄·2H₂O（3）crystallize in the triclinic space group P（No.2）with latice parameters:a=6.0679（8）?,b=6.8658（8）?,c=10.1508（12）?,β=92.557（4）°,Z=1for Na₆Fe（SO₄）₄·2H₂O;a=6.0595（5）?,b=6.8446（6）?,c=10.1149（8）?,β=92.548（2）°,Z=1 for Na₆Co（SO₄）₄·2H₂O;a=6.0490（4）?,b=6.8262（5）?,c=10.0793（7）?,β=92.5470（10）°,Z=1 for Na₆Ni（SO₄）₄·2H₂O,respectively.The three compounds exhibit two-dimensional layers,transition metals are coordinated by four sulfates and two water molecules,transitions metals and six oxygen atoms form distored octahedron.Isolated[Ni（SO₄）₄·2H₂O]^6-anions connect hydrogen bonds to form two-dimensional layers.Na⁺cations reside in structures to keep charge neutrality.Powder X-ray diffraction pattern indicates that the samples are pure phases.The vibrations of S-O and O-H were proved by infrared spetra.compounds（2）and（3）transform into Na₆Co（SO₄）₄ and Na₂Ni（SO₄）₂ in Ar at 500℃.The magnetization experiments for Na₆M（SO₄）₄·2H₂O（M=Fe,Co,Ni）show a nearly linear temperature dependence of the measured magnetic moment down to 2 K,which indicates a paramagnetic behavior for all three compounds.2.Alkali metal transition metal sulfate-oxalates:The space group of K₂Mn（SO₄）（C₂O₄）（4）was monoclinic P2₁/c（No.14）,and lattice parameters were a=5.9066（3）?,b=10.3374（6）?,c=13.2249（8）?,β=91.0670（10）°,Z=4;the space group of Rb₂Mn（SO₄）（C₂O₄）·2H₂O（5）was orthorhombic Pca2₁（No.29）,and lattice parameters were a=10.4350（9）?,b=5.9927（5）?,c=16.5289（13）?,β=90°,Z=4;Rb Fe（SO₄）（C₂O₄）_0.5·H₂O（6）、Cs Mn（SO₄）（C₂O₄）_0.5·H₂O（7）and Cs Fe（SO₄）（C₂O₄）_0.5·H₂O（8）all crystallize in the monoclinic space group P2₁/c（No.14）with lattice parameters:a=7.9193（5）?,b=9.4907（6）?,c=8.8090（6）?,β=95.180（2）°,Z=4 for Rb Fe（SO₄）（C₂O₄）_0.5·H₂O;a=8.0654（11）?,b=9.6103（13）?,c=9.2189（13）?,β=94.564（4）°,Z=4 for Cs Mn（SO₄）（C₂O₄）_0.5·H₂O;and a=7.9377（3）?,b=9.5757（4）?,c=9.1474（4）?,β=96.1040（10）°,Z=4 for Cs Fe（SO₄）（C₂O₄）_0.5·H₂O,respectively.K₂Mn（SO₄）（C₂O₄）exhibit three-dimensional frameworks that are composed of[Fe C₂O₄]_∞and SO₄^2-groups.Adjacent[Fe C₂O₄]_∞are connected by SO₄^2-groups,K⁺cations reside in these tunnels to keep charge neutrality.The structure of Rb₂Mn（SO₄）（C₂O₄）·2H₂O（5）is two-dimensional layer,and Rb⁺and SO₄^2-reside between adjacent[Mn C₂O₄]_∞layers.Rb Fe（SO₄）（C₂O₄）_0.5·H₂O（6）,Cs Mn（SO₄）（C₂O₄）_0.5·H₂O（7）,and Cs Fe（SO₄）（C₂O₄）_0.5·H₂O（8）are isostructural,and the three compounds exhibit three-dimensional framework.The[MO₆]octahedra are linked via SO₄^2-tetrahedra to form infinite chains.The zigzag chains are additional connected via SO₄^2-tetrahedra to form layers.The layers are connected by C₂O₄^2-groups,forming a three-dimensional framework containing one-dimensional tunnels.Rb⁺cations reside in these tunnels to keep charge neutrality.Powder X-ray diffraction pattern indicates that the samples are pure phases.The infrared spectrum confirmed vibrations of S-O,C-C and H-O in crystal structures.From solid state UV-vis-NIR diffuse reflectance spectra of Rb Fe（SO₄）（C₂O₄）_0.5·H₂O（6）,Cs Mn（SO₄）（C₂O₄）_0.5·H₂O（7）,and Cs Fe（SO₄）（C₂O₄）_0.5·H₂O（8）,the band gaps are about2.16 e V,2.90 e V,and 2.21 e V,respectively,it could be judged that the compounds are considered as wide band-gap semiconductors.