Sulfosalts with alkaline earth metals. Centrosymmetric vs acentric interplay in Ba3Sb4.66S10 and Ba2.62Pb1.38Sb4S10 based on the Ba/Pb/Sb ratio. Phases related to arsenosulfide minerals of the rathite group and the novel polysulfide Sr6Sb6S17

The new compounds, Sr6Sb6S17, Ba2.62Pb1.38Sb4S10, and Ba3Sb4.66S10 were prepared by the molten polychalcogenide salt method. Sr6Sb6S17 crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a = 8.2871(9) A, b = 15.352(2) A, c = 22.873(3) A, and Z = 4. This compound presents a new structure type composed of [Sb3S7]5- units and trisulfide groups, (S3)2-, held together by Sr2+ ions. The [Sb3S7]5- fragment is formed from three corner-sharing SbS3 trigonal pyramids. The trisulfide groups are separated from the [Sb3S7]5- unit and embedded between the Sr2+ ions. Ba3Sb4.66S10 and Ba2.62Pb1.38Sb4S10 are not isostructural but are closely related to the known mineral sulfosalts of the rathite group. Ba3Sb4.67S10 is monoclinic P2(1)/c with a = 8.955(2) A, b = 8.225(2) A, c = 26.756(5) A, beta = 100.29(3) degrees, and Z = 4. Ba2.62Pb1.38Sb4S10 is monoclinic P2(1) with a = 8.8402(2) A, b = 8.2038(2) A, c = 26.7623(6) A, beta = 99.488(1) degrees, and Z = 4. The Sb atoms are stabilized in SbS3 trigonal pyramids that share corners to build ribbonlike slabs, which are stitched by Ba/Pb atoms to form layers perpendicular to the c-axis. These materials are semiconductors and show optical band gaps of 2.10, 2.14, and 1.64 eV for Sr6Sb6S17, Ba3Sb4.66S10, and Ba2.62Pb1.38Sb4S10, respectively. Raman spectroscopic characterization is reported. Sr6Sb6S17, Ba3Sb4.66S10, and Ba2.62Pb1.38Sb4S10 melt congruently at 729, 770, and 749 degrees C, respectively.     

Ae2Sb2X4F2 (Ae = Sr, Ba): new members of the homologous series Ae2M(1+n)X(3+n)F2 designed from rock salt and fluorite 2D building blocks

We have designed new compounds within the homologous series Ae2F2M(1+n)X(3+n) (Ae = Sr, Ba; M = main group metal; n = integer) built up from the stacking of 2D building blocks of rock salt and fluorite types. By incrementally increasing the size of the rock salt 2D building blocks, we have obtained two new n = 1 members of this homologous series, namely, Sr2F2Sb2Se4 and Ba2F2Sb2Se4. We then succeeded in synthesizing these compounds using a high-temperature ceramic method. The structure refinements from the powder or single-crystal X-ray diffraction data confirmed presence of the expected alternating stacking of fluorite [Ae2F2] (Ae = Sr, Ba) and rock salt [Sb2Se4] 2D building blocks. However the Ba derivative shows a strong distortion of the [Sb2Se4] block and a concomitant change of the Sb atom coordination likely related to the lone-pair activity.     

半水榴石型化合物Sr_6Sb_4M_3O_(14)(OH)_(10)(M=Co,Mn)的合成、结构与性质

在强碱性水热条件下合成了两种新化合物Sr6Sb4Co3O14(OH)10(SSC)与Sr6Sb4Mn3O14(OH)10(SSM).采用粉末X射线衍射数据,通过Rietveld方法进行了结构分析,讨论了金属离子的拓扑结构.两种化合物均为石榴石-水榴石相关结构,空间群I43d,晶胞参数a分别为1.30634(2)nm(SSC)和1.31367(1)nm(SSM).结构中,SbO6八面体与MO4(M=Co,Mn)四面体共顶点连接,Sb5+-M2+(M=Co,Mn)离子表现为ctn即C3N4型的拓扑结构.拓扑结构中,Sb5+为三连接,过渡金属离子M2+(M=Co,Mn)为四连接.Sb5+离子的拓扑结构为体心立方,而M2+(M=Co,Mn)分布呈类风扇状,相互连接形成thp型拓扑结构(即Th3P4中Th原子之间连接关系).过渡金属离子的分布与化合物表现出的磁性质密切相关,Co2+(Mn2+)间存在反铁磁相互作用.Sr6Sb4Co3O14(OH)10在低温下表现出反铁磁倾斜有序.Sr6Sb4Co3O14(OH)10和Sr6Sb4Mn3O14(OH)10在高温下发生分解,产物主相为双钙钛矿Sr2(Sb,M)2O6(M=Co,Mn).     

Sr2GaScO5, Sr10Ga6Sc4O25, and SrGa0.75Sc0.25O2.5: a play in the octahedra to tetrahedra ratio in oxygen-deficient perovskites

Three different perovskite-related phases were isolated in the SrGa(1-x)Sc(x)O(2.5) system: Sr(2)GaScO(5), Sr(10)Ga(6)Sc(4)O(25), and SrGa(0.75)Sc(0.25)O(2.5). Sr(2)GaScO(5) (x = 0.5) crystallizes in a brownmillerite-type structure [space group (S.G.) Icmm, a = 5.91048(5) ?, b = 15.1594(1) ?, and c = 5.70926(4) ?] with complete ordering of Sc(3+) and Ga(3+) over octahedral and tetrahedral positions, respectively. The crystal structure of Sr(10)Ga(6)Sc(4)O(25) (x = 0.4) was determined by the Monte Carlo method and refined using a combination of X-ray, neutron, and electron diffraction data [S.G. I4(1)/a, a = 17.517(1) ?, c = 32.830(3) ?]. It represents a novel type of ordering of the B cations and oxygen vacancies in perovskites. The crystal structure of Sr(10)Ga(6)Sc(4)O(25) can be described as a stacking of eight perovskite layers along the c axis ...[-(Sc/Ga)O(1.6)-SrO(0.8)-(Sc/Ga)O(1.8)-SrO(0.8)-](2).... Similar to Sr(2)GaScO(5), this structure features a complete ordering of the Sc(3+) and Ga(3+) cations over octahedral and tetrahedral positions, respectively, within each layer. A specific feature of the crystal structure of Sr(10)Ga(6)Sc(4)O(25) is that one-third of the tetrahedra have one vertex not connected with other Sc/Ga cations. Further partial replacement of Sc(3+) by Ga(3+) leads to the formation of the cubic perovskite phase SrGa(0.75)Sc(0.25)O(2.5) (x = 0.25) with a = 3.9817(4) ?. This compound incorporates water molecules in the structure forming SrGa(0.75)Sc(0.25)O(2.5)·xH(2)O hydrate, which exhibits a proton conductivity of ～2.0 × 10(-6) S/cm at 673 K.     

Synthesis, crystal and electronic structures of the new quaternary phases A5Cd2Sb5F (A = Sr, Ba, Eu), and Ba5Cd2Sb5O(x) (0.5<x<0.7)

A new family of quaternary fluoro-antimonides A(5)Cd(2)Sb(5)F (A = Sr, Ba, Eu) and oxyantimonides Ba(5)Cd(2)Sb(5)O(x) (0.5相似文献   

Mg(5.23)Sm(0.77)Sb4: an ordered superstructure derived from the Mg3Sb2 structure type

The ternary polar intermetallic phase Mg(5.231(8))Sm(0.769(8))Sb4 has been obtained from solid-state reactions at 700-850 degrees C in sealed Ta or Nb containers when the synthetic conditions took into account its characteristic incongruent melting point. The compound crystallizes in the trigonal space group P3 (Z = 1) with a = 4.618(1) A and c = 14.902(6) A in a structure that derives from that of Mg3Sb2 (anti-La2O3 type). This composition appears to be near the lower limit of Sm content, and solutions with appreciably higher Sm contents are also stable [Mg(6-x)SmxSb4, x 相似文献   

Orthonitridoborate ions [BN3]6- in oxonitridosilicate cages: synthesis, crystal structure, and magnetic properties of Ba4Pr7[Si12N23O][BN3], Ba4Nd7[Si12N23O][BN3], and Ba4Sm7[Si12N23O][BN3

The isotypic title compounds Ba4Pr7[Si12N23O][BN3], Ba4Nd7[Si12N23O][BN3], and Ba4Sm7[Si12N23O][BN3] were prepared by reaction of Pr, Nd, or Sm, with barium, BaCO3, Si(NH)2, and poly(boron amide imide) in nitrogen atmosphere in tungsten crucibles using a radiofrequency furnace at temperatures up to 1650 C. They were obtained as main products (approximately 70%) embedded in a very hard glass matrix in the form of intense dark green (Pr), orange-brown (Sm), or dark red (Nd) large single crystals, respectively. The stoichiometric composition of Ba4Sm7[Si12N23O][BN3] was verified by a quantitative elemental analysis. According to the single-crystal X-ray structure determinations (Ba4Ln7[Si12N23][BN3], Z= , P6 with Ln = Pr: a = 1225.7(1), c = 544.83(9) pm, R1 = 0.013, wR2 = 0.030; Ln = Nd: a = 1222.6(1), c = 544.6(1) pm, R1 = 0.017, wR2 = .039; Ln = Sm: a = 1215.97(5), c = 542.80(5) pm, R1 = 0.047, wR2 = 0.099) all three compounds are built up by a framework structure [Si12N23O]23- of corner-sharing SiX4 tetrahedrons (X = O, N). The oxygen atoms are randomly distributed over the X positions. The trigonal-planar orthonitridoborate ions [BN3]6- and also the Ln(3)3+ are situated in hexagonal cages of the framework (bond lengths Si-(N/O) 169-179 pm for Ln=Pr). The remaining Ba2+ and Ln3- ions are positioned in channels of the large-pored network. The trigonal-planar [BN3]6- ions have a B-N distance of 147.1(6) pm (for Ln = Pr). Temperature-dependent susceptibility measurements for Ba4Nd7[Si12N23O][BN3] revealed Curie-Weiss behavior above 60 K with an experimental magnetic moment of muexp = 3.36(5) microB/Nd. The deviation from Curie-Weiss behavior below 60 K may be attributed to crystal field splitting of the J = 9/2 ground state of the Nd3+ ions. No magnetic ordering is evident down to 4.2 K.     

Ferromagnetism in a new manganese-related Brownmillerite: La0.5Sr0.5MnO2.5

The topotactic reduction of La0.5Sr0.5MnO3 leads to ordering of the anionic vacancies in the La0.5Sr0.5MnO2.5 composition. The isolated material, which is isostructural with Sr2Fe2O5, crystallises in the brownmillerite structural type with unit cell parameters a=0.54117(3), b=1.67608(12), c=0.54004(3) nm and space group Ibm2. Its microstructural characterisation by means of electron diffraction and high-resolution electron microscopy suggests a complex microstructure arising from the coherent intergrowth of different brownmillerite-type domains that show short-range ordering at the A sub-lattice. The layer structure of La0.5Sr0.5MnO2.5 leads to a double magnetic behaviour where a ferromagnetic two-dimensional component is present.     

Ternary arsenides A2Zn2As3 (A = Sr, Eu) and their stuffed derivatives A2Ag2ZnAs3

The ternary arsenides A(2)Zn(2)As(3) and the quaternary derivatives A(2)Ag(2)ZnAs(3) (A = Sr, Eu) have been prepared by stoichiometric reaction of the elements at 800 °C. Compounds A(2)Zn(2)As(3) crystallize with the monoclinic Ba(2)Cd(2)Sb(3)-type structure (Pearson symbol mC28, space group C2/m, Z = 4; a = 16.212(5) ?, b = 4.275(1) ?, c = 11.955(3) ?, β = 126.271(3)° for Sr(2)Zn(2)As(3); a = 16.032(4) ?, b = 4.255(1) ?, c = 11.871(3) ?, β = 126.525(3)° for Eu(2)Zn(2)As(3)) in which CaAl(2)Si(2)-type fragments, built up of edge-sharing Zn-centered tetrahedra, are interconnected by homoatomic As-As bonds to form anionic slabs [Zn(2)As(3)](4-) separated by A(2+) cations. Compounds A(2)Ag(2)ZnAs(3) crystallize with the monoclinic Yb(2)Zn(3)Ge(3)-type structure (Pearson symbol mC32, space group C2/m; a = 16.759(2) ?, b = 4.4689(5) ?, c = 12.202(1) ?, β = 127.058(1)° for Sr(2)Ag(2)ZnAs(3); a = 16.427(1) ?, b = 4.4721(3) ?, c = 11.9613(7) ?, β = 126.205(1)° for Eu(2)Ag(2)ZnAs(3)), which can be regarded as a stuffed derivative of the Ba(2)Cd(2)Sb(3)-type structure with additional transition-metal atoms in tetrahedral coordination inserted to link the anionic slabs together. The Ag and Zn atoms undergo disorder but with preferential occupancy over four sites centered in either tetrahedral or trigonal planar geometry. The site distribution of these metal atoms depends on a complex interplay of size and electronic factors. All compounds are Zintl phases. Band structure calculations predict that Sr(2)Zn(2)As(3) is a narrow band gap semiconductor and Sr(2)Ag(2)ZnAs(3) is a semimetal. Electrical resistivity measurements revealed band gaps of 0.04 eV for Sr(2)Zn(2)As(3) and 0.02 eV for Eu(2)Zn(2)As(3), the latter undergoing an apparent metal-to-semiconductor transition at 25 K.     

Influence of hydrogen bonding on the assembly of six-membered vanadium borophosphate cluster anions: synthesis and structures of (NH4)2(C2H10N2)6[Sr(H2O)5]2[V2P2BO12](6)10H2O, (NH4)2(C3H12N2)6[Sr(H2O)4]2[V2P2BO12](6)17H2O, and (NH4)3(C4H14N2)4 5[Sr(H2O)5]2[Sr(H2O)4][V2P2BO12]6 10H2O

Three new strontium vanadium borophosphate compounds, (NH4)2(C2H10N2)6[Sr(H2O)5]2[V2P2BO12]6 10H2O (Sr-VBPO1) (1), (NH4)2(C3H12N2)6[Sr(H2O)4]2[V2P2BO12]6 17H2O (Sr-VBPO2) (2), and (NH4)3(C4H14N2)4.5[Sr(H2O)5]2[Sr(H2O)4][V2P2BO12]6 10H2O (Sr-VBPO3) (3) have been synthesized by interdiffusion methods in the presence of diprotonated ethylenediamine, 1,3-diaminopropane, and 1,4-diaminobutane. Compound 1 has a chain structure, whereas 2 and 3 have layered structures with different arrangements of [(NH4) [symbol: see text] [V2P2BO12]6] cluster anions within the layers. Crystal data: (NH4)2(C2H10N2)6[Sr(H2O)5]2[V2P2BO12]6 10H2O, monoclinic, space group C2/c (no. 15), a = 21.552(1) A, b = 27.694(2) A, c = 20.552(1) A, beta = 113.650(1) degrees, Z = 4; (NH4)2(C3H12N2)6[Sr(H2O)4]2[V2P2BO12]6 17H2O, monoclinic, space group I2/m (no. 12), a = 15.7618(9) A, b = 16.4821(9) A, c = 21.112(1) A, beta = 107.473(1) degrees, Z = 2; (NH4)3(C4H14N2)4.5[Sr(H2O)5]2[Sr(H2O)4] [V2P2BO12]6 10H2O, monoclinic, space group C2/c (no. 15), a = 39.364(2) A, b = 14.0924(7) A, c = 25.342(1) A, beta = 121.259(1) degrees, Z = 4. The differences in the three structures arise from the different steric requirements of the amines that lead to different amine-cluster hydrogen bonds.     

A hydrothermal investigation of the 1/2V2O5-H2C2O4/H3PO4/NH4OH system: synthesis and structures of (NH4)VOPO(4).1.5H2O, (NH4)0.5VOPO(4).1.5H2O, (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2](2).3H2O, and (NH4)2[VO(HPO4)]2(C2O4).5H2O

The 1/2V2O5-H2C2O4/H3PO4/NH4OH system was investigated using hydrothermal techniques. Four new phases, (NH4)VOPO(4).1.5H2O (1), (NH4)0.5VOPO(4).1.5H2O (2), (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O (3), and (NH4)2[VO(HPO4)]2(C2O4).H2O (4), have been prepared and structurally characterized. Compounds 1 and 2 have layered structures closely related to VOPO(4).2H2O and A0.5VOPO4.yH2O (A = mono- or divalent metals), whereas 3 has a 3D open-framework structure. Compound 4 has a layered structure and contains both oxalate and phosphate anions coordinated to vanadium cations. Crystal data: (NH4)VOPO(4).1.5H2O, tetragonal (I), space group I4/mmm (No. 139), a = 6.3160(5) A, c = 13.540(2) A, Z = 4; (NH4)0.5VOPO(4).1.5H2O, monoclinic, space group P2(1)/m (No. 11), a = 6.9669(6) A, b = 17.663(2) A, c = 8.9304(8) A, beta = 105.347(1) degrees, Z = 8; (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O, triclinic, space group P1 (No. 2), a = 10.2523(9) A, b = 12.263(1) A, c = 12.362(1) A, alpha = 69.041(2) degrees, beta = 65.653(2) degrees, gamma = 87.789(2) degrees, Z = 2; (NH4)2[VO(HPO4)]2(C2O4).5H2O, monoclinic (C), space group C2/m (No. 12), a = 17.735(2) A, b = 6.4180(6) A, c = 22.839(2) A, beta = 102.017(2) degrees, Z = 6.     

K_2NiF_4型Dy_(0.5)Sr_(1.5)MO_4(M=Mn,Fe,Co,Ni)稀土复合氧化物的合成和催化性能考察

用重稀土镝的氧化物与锶、锰、铁、钴、镍的硝酸盐为原料,制备了A_2BO_4型Dy_(0.5)Sr_(1.5)MO_4(M=Mn,Fe,Co,Ni)稀土复合氧化物,用XRD技术考察了物相,合成了K_2NiF_4型四方结构的Dy_(0.5)Sr_(1.5)MO_4,并研究了其催化性能。对结构容纳因子的适用性作了讨论。     

Doping effects in single-layered La0.5Sr1.5MnO4 manganite

In this paper we report the results of the synthesis and structural, transport, and magnetic characterization of pure La(0.5)Sr(1.5)MnO(4) and B-site lightly doped samples, i.e. La(0.5)Sr(1.5)Mn(0.95)B(0.05)O(4), where B = Ru, Co, and Ni. The choice was made in order to probe the charge ordering/orbital ordering ground state of the monolayered La(0.5)Sr(1.5)MnO(4) manganite as a consequence of the cation doping. It is shown that even a light doping is successful in suppressing the charge and orbital order found in pure La(0.5)Sr(1.5)MnO(4). No long-range magnetic order has been detected in any of the doped samples but the setup of a spin-glass state with a common freezing temperature ( approximately 22 K). Structural parameters show an anisotropy in the lattice constant variation, with the tetragonal distortion increasing as the cell volume reduces, which may suggest a variation in the orbital character of the e(g) electrons along with the overall cation size.     

High-pressure synthesis, crystal structure, and properties of BiPd2O4 with Pd2+ and Pd4+ ordering and PbPd2O4

BiPd(2)O(4) and PbPd(2)O(4) were synthesized at high pressure of 6 GPa and 1500 K. Crystal structures of BiPd(2)O(4) and PbPd(2)O(4) were studied with synchrotron X-ray powder diffraction. BiPd(2)O(4) is isostructural with PbPt(2)O(4) and crystallizes in a triclinic system (space group P1, a = 5.73632(4) ?, b = 6.02532(5) ?, c = 6.41100(5) ?, α = 114.371(1)°, β = 95.910(1)°, and γ = 111.540(1)° at 293 K). PbPd(2)O(4) is isostructural with LaPd(2)O(4) and BaAu(2)O(4) and crystallizes in a tetragonal system (space group I4(1)/a, a = 5.76232(1) ?, and c = 9.98347(2) ? at 293 K). BiPd(2)O(4) shows ordering of Pd(2+) and Pd(4+) ions, and it is the third example of compounds with ordered arrangements of Pd(2+) and Pd(4+) in addition to Ba(2)Hg(3)Pd(7)O(14) and KPd(2)O(3). In PbPd(2)O(4), the following charge distribution is realized Pb(4+)Pd(2+)(2)O(4). PbPd(2)O(4) shows a structural phase transition from I4(1)/a to I2/a at about 240 K keeping basically the same structural arrangements (space group I2/a, a = 5.77326(1) ?, b = 9.95633(2) ?, c = 5.73264(1) ?, β = 90.2185(2)° at 112 K). BiPd(2)O(4) is nonmagnetic while PbPd(2)O(4) exhibits a significant temperature-dependent paramagnetic moment of 0.46μ(B)/f.u. between 2 and 350 K. PbPd(2)O(4) shows metallic conductivity, and BiPd(2)O(4) is a semiconductor between 2 and 400 K.     

New vanadium selenites: centrosymmetric Ca2(VO2)2(SeO3)3(H2O)2, Sr2(VO2)2(SeO3)3, and Ba(V2O5)(SeO3), and noncentrosymmetric and polar A4(VO2)2(SeO3)4(Se2O5) (A = Sr2+ or Pb2+)

Five new vanadium selenites, Ca(2)(VO(2))(2)(SeO(3))(3)(H(2)O)(2), Sr(2)(VO(2))(2)(SeO(3))(3), Ba(V(2)O(5))(SeO(3)), Sr(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)), and Pb(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)), have been synthesized and characterized. Their crystal structures were determined by single crystal X-ray diffraction. The compounds exhibit one- or two-dimensional structures consisting of corner- and edge-shared VO(4), VO(5), VO(6), and SeO(3) polyhedra. Of the reported materials, A(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)) (A = Sr(2+) or Pb(2+)) are noncentrosymmetric (NCS) and polar. Powder second-harmonic generation (SHG) measurements revealed SHG efficiencies of approximately 130 and 150 × α-SiO(2) for Sr(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)) and Pb(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)), respectively. Piezoelectric charge constants of 43 and 53 pm/V, and pyroelectric coefficients of -27 and -42 μC/m(2)·K at 70 °C were obtained for Sr(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)) and Pb(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)), respectively. Frequency dependent polarization measurements confirmed that the materials are not ferroelectric, that is, the observed polarization cannot be reversed. In addition, the lone-pair on the Se(4+) cation may be considered as stereo-active consistent with calculations. For all of the reported materials, infrared, UV-vis, thermogravimetric, and differential thermal analysis measurements were performed. Crystal data: Ca(2)(VO(2))(2)(SeO(3))(3)(H(2)O)(2), orthorhombic, space group Pnma (No. 62), a = 7.827(4) ?, b = 16.764(5) ?, c = 9.679(5) ?, V = 1270.1(9) ?(3), and Z = 4; Sr(2)(VO(2))(2)(SeO(3))(3), monoclinic, space group P2(1)/c (No. 12), a = 14.739(13) ?, b = 9.788(8) ?, c = 8.440(7) ?, β = 96.881(11)°, V = 1208.8(18) ?(3), and Z = 4; Ba(V(2)O(5))(SeO(3)), orthorhombic, space group Pnma (No. 62), a = 13.9287(7) ?, b = 5.3787(3) ?, c = 8.9853(5) ?, V = 673.16(6) ?(3), and Z = 4; Sr(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)), orthorhombic, space group Fdd2 (No. 43), a = 25.161(3) ?, b = 12.1579(15) ?, c = 12.8592(16) ?, V = 3933.7(8) ?(3), and Z = 8; Pb(4)(VO(2))(2)(SeO(3))(4)(Se(2)O(5)), orthorhombic, space group Fdd2 (No. 43), a = 25.029(2) ?, b = 12.2147(10) ?, c = 13.0154(10) ?, V = 3979.1(6) ?(3), and Z = 8.     

Synthesis and characterization of protonated zirconium trisilicate and its exchange phases with strontium

A partially protonated form of the mineral umbite has been prepared by ion exchange of K2ZrSi3O9 x H2O with acetic acid. The protonated phase, compound 1, is assigned the formula H1.45K0.55ZrSi3O9 x 2 H2O and crystallizes in the space group P2(1)/c with unit cell dimensions of a = 7.1002(2), b = 10.1163(3), c = 13.1742(5), and beta = 91.181(1) degrees. The characteristic building blocks of the acid phase are almost identical to those of the parent compound. The framework is composed of polymeric chains of trisilicate groups linked by zirconium atoms, resulting in zeolite-type channels. When viewed down the a axis, two unique ion-exchange channels can be seen. Site 1 is marked by a 12-membered ring and contains 2 cations. Site 2, a 16-membered ring, contains 4 water molecules. Compound 2, consists of a mixed Sr2+ and K+ phase synthesized from 1 by ion exchange with Sr(NO3)2. Compound 2 has the formula K0.34Sr0.83ZrSi3O9 x 1.8 H2O and crystallizes in the same space group P2(1)/c. It has cell dimensions of a = 7.1386(3), b = 10.2304(4), c = 13.1522(4), and beta = 90.222(1) degrees. The Sr2+ cations are distributed evenly among the two exchange sites, showing no preference for either cavity. Compound 3 is the fully substituted Sr phase, SrZrSi3O9 x 2 H2O, and retains the same space group as that of the previous two compounds having unit cell dimensions of a = 7.1425(5), b = 10.2108(8), c = 13.0693(6), and beta = 90.283(1) degrees. The strontium cations show a slight affinity for ion-exchange site 2, having a higher occupancy of 0.535, while site 1 is occupied by the remainder of the Sr2+ cations with an occupancy of 0.465. Batch uptake studies demonstrate a selectivity series among alkaline earth cations of Ba2+ > Sr2+ > Ca2+ > Mg2+.     

Synthesis, structure, and magnetic properties of the oxalate-based bimetallic ferromagnetic chain {[K(18-crown-6)][Mn(H2O)2Cr(ox)3]}infinity (18-crown-6 = C12H24O6, ox = C2O4(2-))

The salt [K(18-crown-6)][Mn(H2O)2Cr(ox)3.0.5(18-crown-6) (1) has been prepared and structurally and magnetically characterized. It crystallizes in the P2(1)/c space group [a = 21.011(2) A, b = 11.265(2) A, c = 15.748(3) A, beta = 105.952(6) degrees , V = 3584(1) A3, and Z = 4] and contains [Mn(H2O)2Cr(ox)3]infinity chains connected through hydrogen bonding to form 2D anionic networks. The magnetic exchange is ferromagnetic [J = +2.23(2) cm(-1)] in the chain and also in between chains, reaching bulk ferromagnetic ordering below 3.5 K.     

Polar intermetallic compounds as catalysts for hydrogenation reactions: synthesis, structures, bonding, and catalytic properties of Ca(1-x)Sr(x)Ni4Sn2 (x=0.0, 0.5, 1.0) and catalytic properties of Ni3Sn and Ni3Sn2

The potential of polar intermetallic compounds to catalyze hydrogenation reactions was evaluated. The novel compounds CaNi4Sn2, SrNi4Sn2, and Ca(0.5)Sr(0.5)Ni(4)Sn(2) were tested as unsupported alloys in the liquid-phase hydrogenation of citral. Depending on the reaction conditions, conversions of up to 21.0 % (253 K and 9.0 MPa hydrogen pressure) were reached. The binary compounds Ni3Sn and Ni3Sn2 were also tested in citral hydrogenation under the same conditions. These materials gave conversions of up to 37.5 %. The product mixtures contained mainly geraniol, nerol, citronellal, and citronellol. The isotypic stannides CaNi4Sn2, Ca(0.5)Sr(0.5)Ni4Sn2, and SrNi4Sn2 were obtained by melting mixtures of the elements in an arc-furnace under an argon atmosphere. Single crystals were synthesized in tantalum ampoules using special temperature modes. The novel structures were established by single-crystal X-ray diffraction. They crystallize in the tetragonal space group I4/mcm with parameters: a=7.6991(7), c=7.8150(8) A, wR2=0.034, 162 F(2) values, 14 variable parameters for CaNi4Sn2; a=7.7936(2), c=7.7816(3) A, wR2=0.052, 193 F(2) values, 15 variable parameters for Ca(0.5)Sr(0.5)Ni4Sn2; and a=7.8916(4), c=7.7485(5) A, wR2=0.071, 208 F(2) values, 14 variable parameters for SrNi4Sn2. The Ca(1-x)Sr(x)Ni(4)Sn(2) (x=0.0, 0.5, 1.0) structures can be represented as a stuffed variant of the CuAl2 type by the formal insertion of one-dimensional infinite Ni-cluster chains [Ni4] into the Ca(Sr)Sn2 substructure. The Ni and Sn atoms form a three-dimensional infinite [Ni4Sn2] network in which the Ca or Sr atoms fill distorted octagonal channels. The densities of states obtained from TB-LMTO-ASA calculations show metallic character for both compounds.     

New metalloligands [M(SC[O]Ph)(4)](-): synthesis and characterization of polymeric [A(MeCN)(x)[M(SC[O]Ph)(4)]] compounds (A = Li,Na and K; M = Ga and In; x = 0-2)

Exploiting the ability of the [M(SC[O]Ph)(4)](-) anion to behave like an anionic metalloligand, we have synthesized [Li[Ga(SC[O]Ph)(4)]] (1), [Li[In(SC[O]Ph)(4)]] (2), [Na[Ga(SC[O]Ph)(4)]] (3), [Na(MeCN)[In(SC[O]Ph)(4)]] (4), [K[Ga(SC[O]Ph)(4)]] (5), and [K(MeCN)(2)[In(SC[O]Ph)(4)]] (6) by reacting MX(3) and PhC[O]S(-)A(+) (M = Ga(III) and In(III); X = Cl(-) and NO(3)(-); and A = Li(I), Na(I), and K(I)) in the molar ratio 1:4. The structures of 2, 4, and 6 determined by X-ray crystallography indicate that they have a one-dimensional coordination polymeric structure, and structural variations may be attributed to the change in the alkali metal ion from Li(I) to Na(I) to K(I). Crystal data for 2 x 0.5MeCN x 0.25H(2)O: monoclinic space group C2/c, a = 24.5766(8) A, b = 13.2758(5) A, c = 19.9983(8) A, beta = 108.426(1) degrees, Z = 8, and V = 6190.4(4) A(3). Crystal data for 4: monoclinic space group P2(1)/c, a = 10.5774(7) A, b = 21.9723(15) A, c = 14.4196(10) A, beta = 110.121(1) degrees, Z = 4, and V = 3146.7(4) A(3). Crystal data for 6: monoclinic space group P2(1)/c, a = 12.307(3) A, b = 13.672(3) A, c = 20.575(4) A, beta = 92.356(4) degrees, Z = 4, and V = 3458.8(12) A(3). The thermal decomposition of these compounds indicated the formation of the corresponding AMS(2) materials.     

类钙钛矿结构新钽酸盐KSr2Ta3O10的合成、结构与层间特性

类钙钛矿结构氧化物是由钙钛矿结构基元与其它类型结构基元组合而成的一种超结构复合氧化物.