Two isostructural tellurite phosphates Ni_(2)M^(Ⅱ)Te^(Ⅳ)_(2)O_(2)(PO_(4))_(2)(OH)_(4)(M^(Ⅱ)=Ni,Zn)have been synthesized via hydrothermal method.Both of them crystalize in monoclinic space group C2/m(No.12).For Ni_(2)ZnTe^(Ⅳ)_(2)O_(2)(PO_(4))_(2)(OH)_(4),a=19.3247(10),b=5.9697(3),c=4.7737(2)Å,β=103.637(5)°,V=535.18(5)Å^(3),Z=2,M_(r)=727.94,S=1.103,D_(c)=4.517 g·cm^(-3),μ(Mo Kα)=11.434 mm^(-1) and F(000)=672,the final R=0.0369and wR=0.1086 for 639 observed reflections with I>2σ(I).The crystal structure of Ni_(2)M^(Ⅱ)Te^(Ⅳ)_(2)O_(2)(PO_(4))_(2)(OH)_(4)(M^(Ⅱ)=Ni,Zn)features a 3D framework composed of[Ni_(2)O_(2)(PO_(4))_(2)]^(6-)layers interconnected by[MTe_(2)O_(2)(OH)_(4)]^(2+)single chains.Different magnetic susceptibility results at low temperature of the two title compounds confirm that Zn(1)completely occupies the Ni(2)position but not partially substitutes both Ni(1)and Ni(2)position atoms.Additionally,the acentric TeO_(3)(OH)_(2) tetragonal pyramids are aligned in an antiparallel manner,resulting in the crystallization of centrosymmetric(C2/m)crystal structure instead of the non-centrosymmetric crystal structure.The investigation of the origin of centrosymmetric crystal structure with strong dipole moment units provides deeper understanding for future rational design for non-centrosymmetric crystal structure.
A vanadyl phosphate containing a new member of tancoite-like single chain, （DAPH2）[VIVO（HPO4）2]·xH20 （x ≈ 0.2, DAP = 1,3-diaminopropane, C3H10N2）, has been synthesized under hydro（solvo）thermal conditions. It crystallizes in orthorhombic space group P21212 （No. 18） with a = 7.1730（14）, b = 19.252（4）, c = 8.6557（17） A, Z= 4, V= 1195.3（4）A3, C3H14.38N2P2VO9.19, Mr = 338.47, Dc = 1.881 g/cm3,μ（MoKa） = 1.138 mm-1 and F（000） = 692. The final full-matrix least-squares refinement converged to R = 0.0408, wR = 0.1046 for 2498 observed reflections with I 〉 2σ（I） and R = 0.0456 and wR = 0.1080 for all data （2750） and S = 1.001. Its one-dimensional 1 structure consists of tancoite-like ∞1 {vIVO（HPO4）2}2- single chains surrounded by DAPH22＋ ions and water molecules. The single chain is built from trans-corner-sharing octahedral {VIV= O…VIV} backbone loop-branched by HPO4 groups like staple forming a new member of tancoite single chain. Due to the special coordination of VIVO6, the ∞1 {VO（HPO4）2-} chain adopts a larger M-O-M angle （V-O-V = 135°） than those of tancoite chains reported before. The corner-sharing linear {VIV = O…VIV} chain structure also leads to a one-dimensional weak antiferromagnetic interaction at low temperature. The magnetic measurements confirm the 4＋ valence state of vanadium. IR and TG results of the title compound are also discussed.
Two new alkali metal germanophosphates,namely,Na_(3)[Ge(OH)(PO_(4))_(2)]·2 H2 O and Li_(2)Na[GeO(HPO_(4))(PO_(4))],have been prepared by solvothermal method,and their crystal structures were determined by single-crystal X-ray diffraction.The title two compounds crystalize in the same orthorhombic space group Pbcm(No.57)and feature similar chain-like structure which is built from zig-zag GeO_(6) octahedral thread loop branched by PO_(4) tetrahedra.For Na_(3)[Ge(OH)(PO_(4))_(2)]·2 H_(2)O,a=10.1650(9),b=13.1975(12),c=6.9751(7)Å,V=935.73(15)Å^(3),Z=4,R=0.0356 and wR=0.1109;and for Li_(2)Na[GeO(HPO_(4))(PO_(4))],a=6.9855(5),b=14.5809(18),c=6.6620(5)Å,V=678.56(11)Å^(3),Z=4,R=0.0286,and w R=0.0762.The partial substitution of Na ions by Li ions not only significantly influences the total structural features and the water molecule contents,but also impacts on their thermal stabilities.Li_(2)Na[GeO(HPO_(4))(PO_(4))]is thermally stable up to 400℃,whereas only 150℃ for Na_(3)[Ge(OH)(PO_(4))_(2)]·2 H2 O.
A new modification of tellurite phosphate, β-Te3O3（PO4）2, has been synthesized under hydrothermal conditions and its crystal structure was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P21/n（No. 14）, with a = 11.115（5）, b = 4.7033（19）, c = 17.287（7） ？, β = 106.086（5）°, V = 868.3（6） ？3, Z = 4, P2 Te3 O11, Mr = 620.74, Dc = 4.748 g/cm3, μ（Mo Kα） = 10.438 mm–1 and F（000） = 1096. The final full-matrix least-squares refinement converged to R = 0.0227, wR = 0.0534 for 1984 observed reflections with I 〉 2σ（I）, and R = 0.0240, w R = 0.0540 for all data（2070） and S = 1.117. β-Te3O3（PO4）2 is polymorphic with the known α-Te3O3（PO4）2（Weil H. M. et al. Z. Anorg. Allg. Chem. 2003, 629, 1068-1072）. The crystal structure of β-Te3O3（PO4）2 features a three-dimensional（3D） network composed of Te6 O2220-hexanuclear clusters interconnected by PO4 groups. Te6 O22 hexanuclear cluster is built from three Te2 O8 dimers（edge-sharing TeO5 square pyramids） linked to each via sharing O-corners. The structure difference between α-and β-forms of Te3O3（PO4）2 lies in the polymerization of tellurite oxides TenOm. 1D infinite 1∞{[Te3 O11]10-} single chains are presented in α-Te3O3（PO4）2, while 0D discrete Te6 O22 hexanuclear clusters are observed for β-Te3O3（PO4）2. Moreover, thermal analyses, infrared spectra and UV-Vis-NIR diffuse reflectance are also presented.
