共查询到20条相似文献,搜索用时 15 毫秒
1.
Theresa Komm 《Journal of solid state chemistry》2005,178(2):454-463
The two non-isotypical rubidium rare-earth(III) thiophosphates Rb3M3[PS4]4 of praseodymium and erbium can easily be obtained by the stoichiometric reaction of the respective rare-earth metal, red phosphorus and sulfur with an excess of rubidium bromide (RbBr) as flux and rubidium source at 950°C for 14 days in evacuated silica tubes. The pale green platelet-shaped single crystals of Rb3Pr3[PS4]4 as well as the pink rods of Rb3Er3[PS4]4 are moisture sensitive. Rb3Pr3[PS4]4 crystallizes triclinically in the space group (, , , α=84.329(4)°, β=88.008(4)°, γ=80.704(4)°; Z=2), Rb3Er3[PS4]4 monoclinically in the space group P21/n (, , , β=95.601(6)°; Z=4). In both structures, there are three crystallographically different rare-earth cations present. (M1)3+ is eightfold coordinated in the shape of a square antiprism, (M2)3+ and (M3)3+ are both surrounded by eight sulfur atoms as bicapped trigonal prisms each with a coordination number of eight as well as for the praseodymium, but better described as CN=7+1 in the case of the erbium compound. These [MS8]13− polyhedra form a layer according to by sharing edges with the isolated [PS4]3− tetrahedra (d(P-S)=200-209 pm, ?(S-P-S)=102-116°). These layers are stacked with a repetition period of three in the case of the praseodymium compound, but of only two for the erbium analog. The rubidium cation (Rb1)+ is located in cavities of these layers and tenfold coordinated in the shape of a tetracapped trigonal antiprism. The also tenfold but more irregularly coordinated rubidium cations (Rb2)+ and (Rb3)+ reside between the layers. 相似文献
2.
Vladimir G. Zubkov Ivan I. Leonidov Alexander P. Tyutyunnik Ludmila L. Surat Marina A. Melkozerova Elena V. Zabolotskaya Dina G. Kellerman 《Journal of solid state chemistry》2010,183(5):1186-1346
The crystal structure of the promising optical materials Ln2M2+Ge4O12, where Ln=rare-earth element or Y; M=Ca, Mn, Zn and their solid solutions has been studied in detail. The tendency of rare-earth elements to occupy six- or eight-coordinated sites upon iso- and heterovalent substitution has been studied for the Y2−xErxCaGe4O12 (x=0-2), Y2−2xCexCa1+xGe4O12 (x=0-1), Y2Ca1−xMnxGe4O12 (x=0-1) and Y2−xPrxMnGe4O12 (x=0-0.5) solid solutions. A complex heterovalent state of Eu and Mn in Eu2MnGe4O12 has been found. 相似文献
3.
G.D. Tsyrenova S.F. Solodovnikov E.T. Khobrakova Z.A. Solodovnikova 《Journal of solid state chemistry》2004,177(6):2158-2167
Phase equilibria in the systems Ag2MoO4-MMoO4 (M=Ca, Sr, Ba, Pb, Ni, Co, Mn) and subsolidus phase relations in the systems Ag2MoO4-MO-MoO3 (M=Ca, Pb, Cd, Mn, Co, Ni) were investigated using XRD and thermal analysis. The systems Ag2MoO4-MMoO4 (M=Ca, Sr, Ba, Pb, Ni) belong to the simple eutectic type whereas in the systems Ag2MoO4-MMoO4 (M=Co, Mn) incongruently melting Ag2M2(MoO4)3 (M=Co, Mn) were formed. In the ternary oxide systems studied no other compounds were found. Low-temperature LT-Ag2Mn2(MoO4)3 reversibly converts into the high-temperature form of a similar structure at 450-500°C. The single crystals of Ag2Co2(MoO4)3 and LT-Ag2Mn2(MoO4)3 were grown and their structures determined (space group , Z=2; lattice parameters are a=6.989(1) Å, b=8.738(2) Å, c=10.295(2) Å, α=107.67(2)°, β=105.28(2)°, γ=103.87(2)° and a=7.093(1) Å, b=8.878(2) Å, c=10.415(2) Å, α=106.86(2)°, β=105.84(2)°, γ=103.77(2)°, respectively) and refined to R(F)=0.0313 and 0.0368, respectively. The both compounds are isotypical to Ag2Zn2(MoO4)3 and contain mixed frameworks of MoO4 tetrahedra and pairs of M2+O6 octahedra sharing common edges. The Ag+ ions are disordered and located in the voids forming infinite channels running along the a direction. The peculiarities of the silver disorder in the structures of Ag2M2(MoO4)3 (M=Zn, Mg, Co, Mn) are discussed as well as their relations with analogous sodium-containing compounds of the structural family of Na2Mg5(MoO4)6. The phase transitions in Ag2M2(MoO4)3 (M=Mg, Mn) of distortive or order-disorder type are suggested to have superionic character. 相似文献
4.
Shane J Crerar 《Journal of solid state chemistry》2004,177(7):2523-2529
The isostructural ternary silicides M2Cr4Si5 (M=Ti, Zr, Hf) were prepared by arc-melting of the elemental components. The single-crystal structure of Zr2Cr4Si5 was determined by X-ray diffraction (Pearson symbol oI44, orthorhombic, space group Ibam, Z=4, a=7.6354(12) Å, b=16.125(3) Å, c=5.0008(8) Å). Zr2Cr4Si5 adopts the Nb2Cr4Si5-type structure, an ordered variant of the V6Si5-type structure. It consists of square antiprisms that have Zr and Cr atoms at the corners and Si atoms at the centers; they share opposite faces to form one-dimensional chains ∞1[Zr4/2Cr4/2Si] surrounded by additional Si atoms and extending along the c direction. In a new interpretation of the structure, additional Cr atoms occupy interstitial octahedral sites between these chains, clarifying the relation between this structure and that of Ta4SiTe4. The formation of short Si-Si bonds in Zr2Cr4Si5 is contrasted with the absence of Te-Te bonds in Ta4SiTe4. The compounds M2Cr4Si5 (M=Ti, Zr, Hf) exhibit metallic behavior and essentially temperature-independent paramagnetism. Bonding interactions were analyzed by band structure calculations, which confirm the importance of Si-Si bonding in these metal-rich compounds. 相似文献
5.
Crystals of Ba5Fe5−xPtxClO13 and Ba5Co5−yPtyClO13 were prepared for x=1.31, 1.51, 1.57, 1.59 and y=0, 0.97 and 1.08 in a BaCl2 flux and investigated by X-ray diffraction methods. These compounds adopt a 10H perovskite structure built from the stacking of BaO3 and BaOCl layers in the sequence (BaO3)4(BaOCl) with space group P63/mmc. The cation sites within the trimeric unit of face-sharing octahedra are occupied by Co or Fe and Pt ions, while the tetrahedral sites formed between BaO3 and BaOCl layers are only occupied by Fe or Co. Moreover, oxygen stoichiometry indicates an average oxidation state for Co and Fe higher than +III, indicating the stabilization of Co4+ and Fe4+. 相似文献
6.
Marie Colmont El Mostafa Ketatni Olivier Mentré 《Journal of solid state chemistry》2003,176(1):221-233
The crystal structure of the new Bi∼3Cd∼3.72Co∼1.28O5(PO4)3 has been refined from single crystal XRD data, R1=5.37%, space group Abmm, a=11.5322(28) Å, b=5.4760(13) Å, c=23.2446(56) Å, Z=4. Compared to Bi∼1.2M∼1.2O1.5(PO4) and Bi∼6.2Cu∼6.2O8(PO4)5, this compound is an additional example of disordered Bi3+/M2+ oxyphosphate and is well described from the arrangement of double [Bi4Cd4O6]8+ (=D) and triple [Bi2Cd3.44Co0.56O4]6+ (=T) polycationic ribbons formed of edge-sharing O(Bi,M)4 tetrahedra surrounded by PO4 groups. According to the nomenclature defined in this work, the sequence is TT/DtDt, where t stands for the tunnels created by PO4 between two subsequent double ribbons and occupied by Co2+. The HREM study allows a clear visualization of the announced sequence by comparison with the refined crystal structure. The Bi3+/M2+ statistic disorder at the edges of T and D entities is responsible for the PO4 multi-configuration disorder around a central P atom. Infrared spectroscopy and neutron diffraction of similar compounds (without the highly absorbing Cadmium) even suggests the long range ordering loss for phosphates. Therefore, electron diffraction shows the existence of a modulation vector q*=1/2a*+(1/3+ε)b* which pictures cationic ordering in the (001) plane, at the crystallite scale. This ordering is largely lost at the single crystal scale. The existence of mixed Bi3+/M2+ positions also enables a partial filling of the tunnels by Co2+ and yields a composition range checked by solid state reaction. The title compound can be prepared as a single phase and also the M=Zn2+ term can be obtained in a biphasic mixture. For M=Cu2+, a monoclinic distortion has been evidenced from XRD and HREM patterns but surprisingly, the orthorhombic ideal form can also be obtained in similar conditions. 相似文献
7.
Contrary to that reported previously, the ternary silicide “Ce6Ni2Si3” does not exist. The melting of this alloy, followed or not by annealing, leads to the existence of the two new ternary compounds, Ce6Ni1.67Si3 and Ce5Ni1.85Si3. The investigation of these ternary silicides based on nickel and Ce6Co1.67Si3 by X-ray diffraction on single crystal reveals an ordered distribution between Ni (or Co) and Si atoms. The nickel or cobalt positions in the chains of face-shared octahedra of cerium are not fully occupied with a strong delocalisation of their electron density. The structural investigations of these compounds confirm that the “Ce6Ni2Si3” and “Ce5Ni2Si3” structural type have to be rewritten as Ce6Ni2−xSi3 and Ce5Ni2−xSi3. Magnetisation and specific heat measurements evidence a magnetic ordering at 3.8(2) K for Ce6Ni1.67Si3 and a heavy fermion behaviour for Ce6Co1.67Si3. 相似文献
8.
This paper describes the hydrothermal syntheses of two isostructural metal bisphosphonates: M2(O3PC6H4PO3)(H2O)2 [M=CoII (1), NiII (2)]. Single-crystal structure determination of compound 1 revealed a pillared layered structure in which the phenyl groups connect the inorganic layers of cobalt phosphonate. Crystal data for 1: orthorhombic, space group Pnnm, a=19.306(5), b=4.8293(12), c=5.6390(14) Å, V=525.7(2) Å3, Z=2. Magnetic susceptibility data indicate that antiferromagnetic interactions are mediated in both cases. 相似文献
9.
Pyrolysis of rare earth (R) polyoxomolybdate, [R2(H2O)12Mo8O27]·xH2O (R=La, Nd and Sm), at 750°C for 2-8 h results in crystallization of R2Mo4O15 compounds. β-La2Mo4O15 crystallizes together with an α-form in monoclinic P21/a (No. 14), a=13.8893(5), b=13.0757(4), c=20.0927(8) Å, β=95.199(2)°, V=3634.1(2) Å3, Z=12, R1(I>2σ(I))=0.048, Rw (all data)=0.116. The structure is built up with {LaOn} (n=9, 10) and {MoOn′} (n′=4-6) polyhedral units. The {LaOn} units are polymerized into a linear {La6O39}∞ chain, while the {MoOn} are connected together to form {Mo4O15} and {Mo7O26} groups. The structure can be related to the α-form by partial rearrangement of O atoms and small shifts of La and Mo atoms. The R2Mo4O15 (R=Nd and Sm) compounds are isomorphous with the previously reported R=Eu and Gd analogs, crystallizing in triclinic, (No. 2), a=9.4989(5) and 9.4076(7), b=11.0088(7) and 10.9583(8), c=11.5665(6) and 11.5234(8) Å, α=104.141(3) and 104.225(3), β=109.838(3) and 109.603(3), γ=108.912(3) and 108.999(3)°, V=987.3(1) and 970.5(1) Å3, Z=3, R1(I>2σ(I))=0.028 and 0.030, Rw (all data)= 0.079 and 0.094, respectively. The crystal structure is composed of {RO8} and {MoOn′} (n′=4-6) polyhedral units. The molybdate units are condensed to give a corrugated {Mo4O17}∞ chain. The square-antiprismatic {RO8} units share their trigonal and square faces, forming {R2O13} and {R2O12} groups, respectively. A very short R?R distance (3.557(6) Å for R=Nd; 3.4956(6) Å for R=Sm) is achieved in the latter unusual {R2O12} group. A common cationic arrangement was found in all the structures in the R2Mo4O15 family: a R-R pair with the shortest separation and surrounding 12 Mo atoms. The symmetry of the cationic arrangement was reduced with an increase of atomic number of R, viz. La>Ce, Pr>Nd-Gd≈Tb, Ho. 相似文献
10.
The rare earth-nickel-indides Tm2Ni1.896(4)In, Tm2.22(2)Ni1.81(1)In0.78(2), Tm4.83(3)Ni2In1.17(3), and Er5Ni2In were synthesized from the elements by arc-melting and subsequent annealing for the latter three compounds. Three indides were investigated by X-ray powder and single crystal diffraction: Mo2FeB2 type, P4/mbm, Z=2, a=731.08(4), c=358.80(3) pm, wR2=0.0201, 178 F2 values, 13 variables for Tm2Ni1.896(4)In, a=734.37(7), c=358.6(1) pm, wR2=0.0539, 262 F2 values, 14 variables for Tm2.22(2)Ni1.81(1)In0.78(2), and Mo5SiB2 type, I4/mcm, a=751.0(2), c=1317.1(3) pm, wR2=0.0751, 317 F2 values, 17 variables for Tm4.83(3)Ni2In1.17(3). X-ray powder data for Er5Ni2In revealed a=754.6(2) and c=1323.3(5) pm. The Mo2FeB2 type structures of Tm2Ni1.896(4)In and Tm2.22(2)Ni1.81(1)In0.78(2) are intergrowths of slightly distorted CsCl and AlB2 related slabs, however, with different crystal chemical features. The nickel sites within the AlB2 slabs are not fully occupied in both indides. Additionally In/Tm mixing is possible at the center of the CsCl slab, as is evident from the structure refinement of Tm2.22(2)Ni1.81(1)In0.78(2). The Mo5SiB2 type structures of Tm4.83(3)Ni2In1.17(3) and Er5Ni2In can be considered as an intergrowth of distorted CuAl2 and U3Si2 related slabs in an ABA′B′ stacking sequence along the c-axis. Again, one thulium site shows Tm/In mixing. The U3Si2 related slab has great structural similarities with the Mo2FeB2 type structure of Tm2Ni1.896(4)In and Tm2.22(2)Ni1.81(1)In0.78(2). The crystal chemical peculiarities and chemical bonding in these intermetallics are briefly discussed. 相似文献
11.
Kwasi Mitchell 《Journal of solid state chemistry》2004,177(3):709-713
The six LnYbQ3 compounds β-LaYbS3, LaYbSe3, CeYbSe3, PrYbSe3, NdYbSe3, and SmYbSe3 have been synthesized from high-temperature solid-state reactions of the constituent elements at 1223 K. The compounds are isostructural to UFeS3 and crystallize in the space group Cmcm of the orthorhombic system with four formula units in a cell. Cell constants (Å) at 153 K are: β-LaYbS3, 3.9238(8), 12.632(3), 9.514(2); LaYbSe3, 4.0616(8), 13.094(3), 9.932(2); CeYbSe3, 4.0234(5), 13.065(2), 9.885(1); PrYbSe3, 4.0152(5), 13.053(2), 9.868(1); NdYbSe3, 4.0015(6), 13.047(2), 9.859(1); SmYbSe3, 3.9780(9), 13.040(3), 9.860(2). The structure is composed of layers of YbQ6 (Q=S or Se) octahedra that alternate with layers of LnQ8 bicapped trigonal prisms along the b-axis. Because there are no Q-Q bonds in the structure the formal oxidation states of Ln/Yb/Q are 3+/3+/2−. Magnetic susceptibility measurements indicate that CeYbSe3 and SmYbSe3 are Curie-Weiss paramagnets over the temperature range 5-300 K. 相似文献
12.
Crystals of Pd2MCh2 (M=Fe, Co, Ni; Ch=Se, Te) were synthesized by heating the elements at 823-1323 K in silica ampoules under argon atmosphere. Their structures were determined by single-crystal X-ray diffraction at room temperature. The metallic compounds crystallize in a variant of the K2ZnO2 type (Ibam, Z=4, Pd2CoSe2: a=5.993(1), b=10.493(2), c=5.003(1) Å; Pd2FeSe2: a=5.960(1), b=10.576(2), c=5.078(1) Å; Pd2CoTe2: a=6.305(1), b=11.100(2), c=5.234(1) Å; Pd2NiTe2: a=6.286(1), b=11.194(2), c=5.157(1) Å). One-dimensional tetrahedra chains with remarkably short M—M bonds run along [001], separated by [Pd2] dumbbells with palladium in fivefold coordination of selenium or tellurium atoms. The structure may also be described as a filled variant of the SiS2 type. M atoms occupy of the tetrahedral voids and the Pd atoms fill all octahedral voids in a distorted ccp motif of chalcogen atoms. Even though the Pd2MCh2 compounds are isotypic to K2ZnO2 from the crystallographic viewpoint, we find a different bonding situation with additional homo- and heteronuclear metal-metal bonds between the Pd and Co atoms. The electronic structures and topologies of the electron densities of Pd2CoSe2 and isotypic Na2CoSe2 are analyzed and compared by using Bader's AIM theory. Different values of topological charge transfer and electron density flatness indices uncover striking quantitative differences in the nature of chemical bonding between the metallic compound Pd2CoSe2 and nonmetallic Na2CoSe2. 相似文献
13.
14.
Klara M. Khal’baeva Elena G. Khaikina Yuliya M. Kadyrova Zoya A. Solodovnikova 《Journal of solid state chemistry》2010,183(3):712-719
The systems M2MoO4-Fe2(MoO4)3 (M=Rb, Cs) were shown to be non-quasibinary joins of the systems M2O-Fe2O3-MoO3. New compounds M3FeMo4O15 were revealed along with the known MFe(MoO4)2 and M5Fe(MoO4)4. The unit cell parameters of the new compounds are a=11.6192(2), b=13.6801(3), c=9.7773(2) Å, β=92.964(1)°, space group P21/c, Z=4 (M=Rb) and a=11.5500(9), b=9.9929(7), c=14.513(1) Å, β=90.676(2)°, space group P21/n, Z=4 (M=Cs). In the structures of M3FeMo4O15 (M=Rb, Cs), a half of the FeO6 octahedra share two opposite edges with two MoO6 octahedra linked to other FeO6 octahedra through the bridged MoO4 tetrahedra by means of the common oxygen vertices to form the chains along the a axis. The difference between the structures is caused by diverse mutual arrangements of the adjacent polyhedral chains. 相似文献
15.
Two metal chalcogenides, Hg2Te2X2 (XBr, I): 3-D framework constructed from novel left-handed helices
Wen-Tong Chen Ming-Sheng Wang Gang Xu Jin-Shun Huang 《Journal of solid state chemistry》2006,179(11):3394-3399
Two isostructural metal chalcogenides, Hg2Te2Br2 (1) and Hg2Te2I2 (2), were obtained by solid-state reactions and structurally characterized. Compounds 1 and 2 crystallize in the acentric space group P43212 of the tetragonal system with eight formula units in a cell: a=10.2388(9), c=14.480(2) Å, V=1518.0(3) Å3, R1/wR2=0.0670/0.1328 for 1 and a=10.711(3), c=15.025(8) Å, V=1724(1) Å3, R1/wR2=0.0637/0.1233 for 2. Both compounds are characterized by a three-dimensional (3-D) framework structure, which is composed by interconnected left-handed helices formed by both tetrahedral and trigonal Hg atoms. Optical absorption spectra of 1 and 2 reveal the presence of sharp optical gaps of 2.06 and 1.85 eV, respectively, suggesting that both materials are semiconductors. TG-DTA measurements show that both compounds are thermally stable up to 200 °C. The composition of both compounds is well confirmed by the semiquantitative microscope analyses. 相似文献
16.
Andriy V. Tkachuk 《Journal of solid state chemistry》2004,177(11):4136-4141
Four new ternary compounds Zr5M1-xPn2+x (M=Cr, Mn; Pn=Sb, Bi) were synthesized by arc-melting and annealing at 800 °C. They crystallize in the tetragonal W5Si3-type structure. The crystal structure of Zr5Cr0.49(2)Sb2.51(2) was refined from powder X-ray diffraction data by the Rietveld method (Pearson symbol tI32, tetragonal, space group I4/mcm, Z=4, a=11.1027(6) Å, c=5.5600(3) Å). Four-probe electrical resistivity measurements on sintered polycrystalline samples indicated metallic behavior. Magnetic susceptibility measurements between 2 and 300 K revealed temperature-independent Pauli paramagnetism for Zr5Cr1-xSb2+x and Zr5Cr1-xBi2+x, but a strong temperature dependence for Zr5Mn1-xSb2+x and Zr5Mn1-xBi2+x which was fit to the Curie-Weiss law for the latter with θ=-11.3 K and μeff=1.81(1) μB. Band structure calculations for Zr5Cr0.5Sb2.5 support a structural model in which Cr and Sb atoms alternate within the chain of interstitial sites formed at the centers of square antiprismatic Zr8 clusters. 相似文献
17.
Single crystals of CsHo3Te5 and Cs3Tm11Te18 have been grown as byproducts in the synthesis of CsLnZnTe3 (Ln=Ho or Tm) through the reaction of Ln, Zn, and Te with a CsCl flux at 850 °C. The crystal structures have been determined from single-crystal X-ray diffraction data. CsHo3Te5 crystallizes in space group Pnma of the orthorhombic system whereas Cs3Tm11Te18 crystallizes in the space group C2/m of the monoclinic system. Each of the compounds adopts a three-dimensional structure; each possesses tunnels built from LnTe6 octahedra that are filled with Cs atoms. The pseudo-rectangular tunnel in CsHo3Te5 is large enough in cross-section to accommodate two symmetrically equivalent Cs atoms. In the Cs3Tm11Te18 structure there are two different sized tunnels: the smaller one is only large enough to host one Cs atom per unit cell whereas the larger one can accommodate two Cs atoms. The electronic structure of CsHo3Te5 was calculated. The band gap is estimated to be about 1.2 eV, consistent with the black color of the crystals. 相似文献
18.
Volodymyr Babizhetskyy Arndt Simon Kurt Hiebl 《Journal of solid state chemistry》2010,183(10):2343-2351
The ternary rare-earth boride carbides R15B4C14 (R=Y, Gd-Lu) were prepared from the elements by arc-melting followed by annealing in silica tubes at 1270 K for 1 month. The crystal structures of Tb15B4C14 and Er15B4C14 were determined from single crystal X-ray diffraction data. They crystallize in a new structure type in space group P4/mnc (Tb15B4C14: a=8.1251(5) Å, c=15.861(1) Å, Z=2, R1=0.041 (wR2=0.088) for 1023 reflections with Io>2σ(Io); Er15B4C14: a=7.932(1) Å, c=15.685(2) Å, Z=2, R1=0.037 (wR2=0.094) for 1022 reflections with Io>2σ(Io)). The crystal structure contains discrete carbon atoms and bent CBC units in octahedra and distorted bicapped square antiprisms, respectively. In both structures the same type of disorder exists. One R atom position needs to be refined as split atom position with a ratio 9:1 indicative of a 10% substitution of the neighboring C4− by C24−. The actual composition has then to be described as R15B4C14.2. The isoelectronic substitution does not change the electron partition of R15B4C14 which can be written as (R3+)15(C4−)6(CBC5−)4•e−. The electronic structure was studied with the extended Hückel method. The investigated compounds Tb15B4C14, Dy15B4C14 and Er15B4C14 are hard ferromagnets with Curie temperatures TC=145, 120 and 50 K, respectively. The coercive field BC=3.15 T for Dy15B4C14 is quite remarkable. 相似文献
19.
Structures of the double perovskites Ba2M(II)M ′(VI)O6 (M=Ca, Sr, M′=Te, W, U) at room temperature have been investigated by the Rietveld method using X-ray and neutron powder diffraction data. For double perovskites with M=Sr, the observed space groups are I2/m (M′ =W) and (M′=Te), respectively. In the case of M=Ca, the space groups are either monoclinic P21/n (M′=U) or cubic (M′=W and Te). The tetragonal and orthorhombic symmetry reported earlier for Ba2SrTeO6 and Ba2CaUO6, respectively, were not observed. In addition, non-ambient X-ray diffraction data were collected and analyzed for Ba2SrWO6 and Ba2CaWO6 in the temperature range between 80 and 723 K. It was found that the rhombohedral structure exists in Ba2SrWO6 above room temperature between the monoclinic and the cubic structure, whereas the cubic Ba2CaWO6 undergoes a structural phase transition at low temperature to the tetragonal I4/m structure. 相似文献
20.
Two novel three-dimensional five-connected coordination polymers [M2(C3H2O4)2(H2O)2(μ2-hmt)]n with 4466 topologies (M=Zn, Cu; hmt=hexamethylenetetramine) were synthesized and characterized by elemental analysis, crystal structure, IR, thermal gravimetric analyses. Both [Zn2(C3H2O4)2(H2O)2(μ2-hmt)]n and [Cu2(C3H2O4)2(H2O)2(μ2-hmt)]n all crystallize in the orthorhombic system, space group Imm2, and with Z=2. Metal ions have all octahedral geometry coordinated by four oxygen atoms from three malonates, one oxygen atom from a water molecule and one nitrogen atom of hmt ligand. Each malonate binds a metal ion with its two oxygen atoms in a chelating mode and connects to adjacent two metal ions with another two oxygen atoms to form an infinite wavy layer. The layers are bridged by μ2-hmt molecules to form a three-dimensional framework with channels. The magnetic susceptibility data show there is a weak antiferromagnetic exchange interaction in the complex [Cu2(C3H2O4)2(H2O)2(μ2-hmt)]n. 相似文献