Hydrothermal Synthesis and Crystal Structure of [(CH3NH3)1.03K2.97]Sb12S20·1.34H2O

A novel thioantimonate(III) [(CH₃NH₃)_1.03K_2.97]Sb₁₂S₂₀·1.34H₂O was synthesized hydrothermally. It crystallizes in space groupP , witha=11.9939(7) Å,b=12.8790(8) Å,c=14.9695(9) Å,α=100.033(1)°,β=99.691(1)°,γ=108.582(1)°,V=2095.3(2) ų, andZ=2. The structure is determined from single crystal X-ray diffraction data collected at room temperature and refined toR(F)=0.037. In the crystal structure, each Sb(III) atoms has short bonds (2.37–2.58 Å) to three S atoms. The pyramidal [SbS₃] groups share common S atoms forming two types of centrosymmetric [Sb₁₂S₂₀] rings with the same topology. These rings are interconnected by weaker Sb–S bonds (2.92–3.29 Å) into 2-dimensional layers. Adjacent layers are parallel with K⁺and CH₃NH⁺₃ions and H₂O molecules located between them. Variation of bond valence sums calculated for the Sb(III) cations is found to be correlated with the coordination geometry. This is interpreted as due to the stereochemical activity of their lone electron pairs.     

Ba5Ti12Sb19+x, a polar intermetallic compound with a stuffed γ-brass structure

The polar intermetallic compound Ba₅Ti₁₂Sb_19+x (x0.2) has been synthesized by reaction of the elements. Single-crystal X-ray diffraction analysis revealed that it adopts a new structure type (Ba₅Ti₁₂Sb_19.102(6), space group , Z=2, a=12.4223(11) Å, V=1916.9(3) Å³). The set of Ba and Sb sites corresponds to the structure of Cu₉Al₄, a γ-brass type with a primitive cell. A complex three-dimensional framework of Ti atoms, in the form of linked planar Ti₉ clusters, is stuffed within the γ-brass-type Ba–Sb substructure. Notwithstanding its relationship to the γ-brass structure, the compound does not appear to conform to the Hume–Rothery electron concentration rules. Band structure calculations on an idealized Ba₅Ti₁₂Sb₁₉ model suggest that the availability of bonding states above the Fermi level is responsible for the partial occupation, but only to a limited degree, of an additional Sb site within the structure. Magnetic measurements indicated Pauli paramagnetic behaviour.     

Dy5Ni0.66Bi2.34 and Lu5Ni0.56Sb2.44 – Substitution derivatives with the orthorhombic Yb5Sb3-type structure. Magnetocaloric effect of Dy5Ni0.66Bi2.34

Dy₅Ni_0.66Bi_2.34 and Lu₅Ni_0.56Sb_2.44 were synthesized by arc-melting and were found to adopt an orthorhombic Yb₅Sb₃-type structure. Cell parameters are a = 12.075(2), b = 9.165(2), c = 8.072(1) Å for Dy₅Ni_0.66Bi_2.34 and a = 11.6187(9), b = 8.933(1) and c = 7.8377(6) Å for Lu₅Ni_0.56Sb_2.44. Dy₅Ni_0.66Bi_2.34 undergoes a step-like ferromagnetic transition around 66 K. Magnetocaloric effect in terms of the magnetic entropy change, ΔS, reaches −3.73 J/kg K at 75 K for Dy₅Ni_0.66Bi_2.34.     

Ternary Antimonide EuSn3Sb4 and Related Metallic Zintl Phases

The ternary Zintl compound europium tin antimonide, EuSn₃Sb₄, has been synthesized at 900°C in the presence of a tin flux, and its structure has been determined by single-crystal X-ray diffraction methods. It crystallizes in the orthorhombic space group D¹⁶_2h-Pnma with a=9.954(2), b=4.3516(7), c=22.650(4) Å, and Z=4 at 22°C. EuSn₃Sb₄ is isostructural to SrSn₃Sb₄; it possesses channels defined by an anionic framework of shared SnSb₄ tetrahedra, SnSb₃ trigonal pyramids, and Sb–Sb zigzag chains, and it is filled by Eu²⁺ cations. Resistivity measurements indicate weakly metallic behavior for ASn₃Sb₄ (A=Eu, Sr) and the structurally related Ba₂Sn₃Sb₆. The anisotropic metallic nature of these compounds is explained through extended Hückel band structure calculations.     

Synthesis and crystal structure analysis of Sr8Cu3In4N5 and Sr0.53Ba0.47CuN

Single crystals of new quaternary compounds Sr₈Cu₃In₄N₅ and Sr_0.53Ba_0.47CuN were prepared, respectively, from a Sr–Cu–In–Na melt under 7 MPa of N₂ and from a Sr–Ba–Cu–In–Na melt under 0.5 MPa of N₂ by slow cooling from 1023 to 823 K. The crystal structures were determined by single-crystal X-ray diffraction. Sr₈Cu₃In₄N₅ has an orthorhombic structure (space group, Immm, Z=2, a=3.8161(5) Å, b=12.437(2) Å, c=18.902(2) Å), and is isostructural with Ba₈Cu₃In₄N₅. It contains nitridocuprates of isolated units ⁰[CuN₂] and one-dimensional linear chains _∝¹[CuN_2/2] and one-dimensional indium clusters _∝¹[In₂In_2/2]. Sr_0.53Ba_0.47CuN crystallizes in an orthorhombic cell, space group Pbcm, Z=4, a=5.4763(7) Å, b=9.2274(12) Å, c=9.0772(12) Å. The structure contains infinite zig-zag chains _∝¹[CuN_2/2] which kink at every second nitrogen atom.     

Crystal structure, magnetic properties and conductivity of CuSbTeO3Cl2

CuSbTeO₃Cl₂ has been isolated during an investigation of the system Cu₂O:TeCl₄:Sb₂O₃:TeO₂. The new compound is light yellow and crystallises in the monoclinic system, space group C2/m, a=20.333(5) Å, b=4.0667(9) Å, c=10.778(2) Å, Z=6. The structure is layered and is built up from corner and edge sharing [(Sb,Te)O₄E] trigonal bipyramids that have the lone pair (E) directed towards one of the equatorial positions, those groups build up [(Sb,Te)₂O₃E₂⁺]_n layers. The copper and the chlorine atoms are located in between those layers. There are two different Cu positions. The [Cu1Cl₄] group is a slightly distorted tetrahedron and these tetrahedra make up chains by corner sharing. The electron density for the half occupied Cu2 atom is spread out in the structure like a worm that run along the b-axis in the space in between two chains of [Cu1Cl₄] tetrahedrons. Analysis of the diamagnetic response in magnetic susceptibility measurements is in perfect agreement with a Cu⁺ valence. Conductivity measurements in the temperature range 355–590 K gives an activation energy of 0.55 eV. The delocalised Cu2 position in the structure suggests that the compound is a Cu⁺ ionic conductor along the b-axis.     

(Nb2W4O19), TMA2, Na4(OH2)14(SO4): a new layered structure with Lindqvist heteropolyanions, XAS characterization of the HPAs

The new (Nb₂W₄O₁₉),TMA₂, Na₄(OH₂)₁₄(SO₄) has been evidenced as a minor phase during the Nb₂W₄O₁₉TMA (tetramethylammonium) salt synthesis. Its crystal structure has been refined from single crystal X-ray diffraction data, system monoclinic, a=10.166(5) Å, b=17.93(1) Å, c=24.81(1) Å, β=93.057(7)°, space group (S.G.) C2/c, Z=4, R₁=3.96%, wR₁=4.50%. It shows the stacking of cationic and anionic bidimensional layers. The anionic layer of formula [(Nb₂W₄O₁₉), TMA₂ ]²⁻ is formed of isolated Lindqvist HPAs surrounded by TMA groups. The isolated layers adopt a trigonal symmetry that is lost in the crystal by the association of the cationic sheets. These later, of formula [Na₄(OH₂)₁₄(SO₄)]²⁺ form porous net-like sheets with nearly circular cavities of diameter 7.5 Å. groups host the available cavities in a disordered manner. The cohesion between the sheets is performed by both electrostatic interactions and a set of hydrogen bonds. In the cationic layers, the highly symmetrical surrounding of HPAs by TMA groups yields a homogeneous electrostatic field at their external surface leading to a statistic Nb/W disorder over the three available independent metallic positions. Then, XAS experiments at the L₁/L₃-W edge complementarily helped to highlight the preferential cis configuration of (Nb₂W₄O₁₉)⁴⁻ anions, help to the strong Nb vs W contrast in their contribution to the backscattering paths. Previously to these experiments, it was of course checked that both the two phases present in the prepared sample contain Nb₂W₄O₁₉ anions with nearly unchanged geometry.     

An XRPD ab-initio structural determination of La2RuO5

The crystal structure of a new oxide, La₂RuO₅, was determined ab initio using conventional laboratory X-ray powder diffraction. Combining X-ray and electron diffraction techniques, we found that the new phase crystallized in the monoclinic system with the space group P2₁/c (SG no.14) and the cell parameters a=9.1878(2) Å, b=5.8313(2) Å, c=7.9575(2) Å and β=100.773(2)° (V=418.8 ų, Z=4). The structural determination with the Patterson method and Fourier difference syntheses and the final Rietveld refinement were performed by means of the JANA2000 program. The structure is built up from the regular stacking of a two octahedra thick [LaRuO₄]_∞ zigzag perovskite slab and an original 3.4 Å thick [LaO]_∞ slab which constitutes the key feature of this new structure.     

New Layered Materials in the K–In–Ge–As System: K8In8Ge5As17and K5In5Ge5As14

Exploratory synthesis in the K–In–Ge–As system has yielded the unusual layered compounds K₈In₈Ge₅As₁₇(1) and K₅In₅Ge₅As₁₄(2), both of which contain In–Ge–As layers with interleaved potassium ions, Ge–Ge bonds, InAs₄tetrahedra, As–As bonds, and rows of Ge₂As₆dimers. Compound 1 has As₃groups, while compound 2 has infinite As ribbons on both faces of each layer. Unlike compound 1, compound 2 has substitutional defects where indium partially occupies each of the three independent germanium sites in the ratio of 1:5 for In:Ge. This partial occupancy makes 2 an electron-precise compound. The Ge(In)–Ge(In) bond of 2 is longer than the Ge–Ge bond of 1, and this bond lengthening effect was confirmed by performing DFT-MO calculations on the model compounds H₃Ge–GeH₃and H₃Ge–InH⁻₃. Possible implications of electron imprecise formulas determined by X-ray crystal structure determinations are discussed. Compound 1: space groupP2₁/cwitha=18.394 (8) Å,b=19.087 (7) Å,c=25.360 (3) Å,β=105.71 (2)°,V=8571 (4) ų, andD_calcd=4.45g/cm³forZ=4. Refinement on 4455 reflections yieldedR(R_w)=6.8%(7.8%). Compound 2: space groupC2/mwitha=40.00 (1) Å,b=3.925 (2) Å,c=10.299 (3),β=99.97 (2)°,V=1592 (1) ų, andD_calcd= 4.55g/cm³forZ=8. Refinement on 1206 reflections yieldedR(R_w)=5.6% (5.7%).     

Synthesis and characterization of [Zn(2,2′-bipy)]2(H2PO3)4: A neutral zinc phosphite cluster containing ZnO3N2 and H2PO3 units

The hydrothermal synthesis, crystal structure and some properties of a zinc phosphite with a neutral cluster, [Zn(2,2′-bipy)]₂(H₂PO₃)₄, are reported. This compound crystallizes in the triclinic system of space group P-1 (No. 2), a=8.3067(5) Å, b=8.9545(4) Å, c=10.0893(6) Å, α=95.448(2)°, β=99.7530(10)°, γ=103.461(2)°, V=712.23(7) ų, Z=1. The cluster consists of 4-membered rings formed by alternating ZnO₃N₂ square pyramids and H₂PO₃ pseudo pyramids, with two “hanging” H₂PO₃ groups attached to each of the Zn centers. The clusters are linked together by extensive multipoint hydrogen bonding involving the phosphite units to form a sheet-like structure. This compound represents the first example of zinc phosphite with P---OH bonds. An intense photoluminescence was observed from this compound upon photoexcitation at 388 nm.     

Synthesis, crystal structures, phase transition characterization and thermal decomposition of a new dabcodiium hexaaquairon(II) bis(sulfate): (C6H14N2)[Fe(H2O)6](SO4)2

The crystal structures of 1,4-diazabicyclo[2.2.2]octane (dabco)-templated iron sulfate, (C₆H₁₄N₂)[Fe(H₂O)₆](SO₄)₂, were determined at room temperature and at −173 °C from single-crystal X-ray diffraction. At 20 °C, it crystallises in the monoclinic symmetry, centrosymmetric space group P2₁/n, Z=2, a=7.964(5), b=9.100(5), c=12.065(5) Å, β=95.426(5)° and V=870.5(8) ų. The structure consists of [Fe(H₂O)₆]²⁺ and disordered (C₆H₁₄N₂)²⁺ cations and (SO₄)²⁻ anions connected together by an extensive three-dimensional H-bond network. The title compound undergoes a reversible phase transition of the first-order at −2.3 °C, characterized by DSC, dielectric measurement and optical observations, that suggests a relaxor–ferroelectric behavior. Below the transition temperature, the compound crystallizes in the monoclinic system, non-centrosymmetric space group Cc, with eight times the volume of the ambient phase: a=15.883(3), b=36.409(7), c=13.747(3) Å, β=120.2304(8)°, Z=16 and V=6868.7(2) ų. The organic moiety is then fully ordered within a supramolecular structure. Thermodiffractometry and thermogravimetric analyses indicate that its decomposition proceeds through three stages giving rise to the iron oxide.     

An extended open framework based on disordered [Nb6Cl9O3(CN)6] cluster units: Synthesis and crystal structure of Cs3Mn[Nb6Cl9O3(CN)6]0.6H2O

The synthesis and crystal structure of Cs₃Mn[Nb₆Cl₉O₃(CN)₆]0.6H₂O are described in this work. It crystallizes in the cubic system (space group Fm-3m; a=15.708(5) Å) and is characterized by a static orientational disorder of the [Nb₆Cl₉O₃(CN)₆]⁵⁻ cluster units. It results in a framework structurally related to that encountered in the well known Prussian Blue family prepared for different hexacyanometallates. The charge of the framework is compensated by cesium cations that are located in the tetrahedral cavities of the c.f.c. lattice of units along with water molecules. We will evidence the features that act in the crystallization of solid state compounds built up from ordered or disordered units as well as the influence of orientational disorder on interatomic distances obtained from single-crystal X-ray diffraction investigations.     

New complex oxides of the A3n+3mA′nB3m+nO9m+6n family: Ba6A′Mn4O15 (A′=Mg, Ni)

Complex oxides Ba₆AMn₄O₁₅, where A=Mg (I) and Ni (II), belonging to the homologous series A_3n+3mA′_nB_3m+nO_9m+6n (n=1, m=1) were obtained by solid state reaction method from Ba carbonate and oxides MgO, NiO, MnO₂. Both new oxides are incommensurate. Their crystal structures were interpreted as composite ones with two subcells: a=10.042(3) Å, c₁=4.318(2) Å, c₂=2.565(1) Å, c₁/c₂=1.6834 for (I) and a=10.044(3) Å, c₁=4.308(2) Å, c₂=2.551(1) Å, c₁/c₂=1.6887 for (II). Magnetic susceptibility measurements in the range 2–850 K revealed antiferromagnetic correlations in Ba₆MgMn₄O₁₅ (T_N=7 K) and a pseudo-square-planar environment of some Ni²⁺ cations in Ba₆NiMn₄O₁₅.     

Niobium Thiobromide, Nb3SBr7, with Triangle Nb3 Cluster: Structure and Bonding

The reaction of Nb, S, and Br₂ in a sealed quartz ampoule at 550°C yielded Nb₃SBr₇. The structure of Nb₃SBr₇ determined by the single-crystal X-ray diffraction method (P3m1, a= 7.1012(6) Å, c = 6.3040(9) Å, V = 275.30(9) ų, Z = 1, d_calc = 5.248(2) g/cm³, R = 0.0395, R_w = 0.0392) consists of one-layer packing of {[Nb₃SBr₃]Br_6/2Br_3/3}²_∞ layers. The molecular orbitals of the model anions [Nb₃Br₁₃]^5- and [Nb₃SBr₁₂]^5-, which involve the triangle Nb₃ cluster with the nearest ligand environment in the structures of Nb₃Br₈ and Nb₃SBr₇, respectively, were calculated by applying the extended Hückel method. The HOMO in [Nb₃Br₁₃]^5- has slightly metal-metal bonding character which is consistent with an Nb-Nb bond length increase from 2.88 Å in a seven-electron Nb₃Br₈ to 2.896(1) Å in a six-electron Nb₃SBr₇. The bonding schemes are in accordance with magnetic properties of Nb₃Br₈, which is paramagnetic, and Nb₃SBr₇, which is diamagnetic.     

Syntheses, crystal structures and spectroscopic properties of KEu[AsS4], K3Dy[AsS4]2 and Rb4Nd0.67[AsS4]2

Three rare earth compounds, KEu[AsS₄] (1), K₃Dy[AsS₄]₂ (2), and Rb₄Nd_0.67[AsS₄]₂ (3) have been synthesized employing the molten flux method. The reactions of A₂S₃ (A = K, Rb), Ln (Ln = Eu, Dy, Nd), As₂S₃, S were accomplished at 600 °C for 96 h in evacuated fused silica ampoules. Crystal data for these compounds are: 1, monoclinic, space group P2₁/m (no. 11), a = 6.7276(7) Å, b = 6.7190(5) Å, c = 8.6947(9) Å, β = 107.287(12)°, Z = 2; 2, monoclinic, space group C2/c (no. 15), a = 10.3381(7) Å, b = 18.7439(12) Å, c = 8.8185(6) Å, β = 117.060(7)°, Z = 4; 3, orthorhombic, space group Ibam (no. 72), a = 18.7333(15) Å, b = 9.1461(5) Å, c = 10.2060(6) Å, Z = 4. 1 is a two-dimensional structure with ²_∞[Eu(AsS₄)]⁻ layers separated by potassium cations. Within each layer, distorted bicapped trigonal [EuS₈] prisms are linked through distorted [AsS₄]³⁻ tetrahedra. Each Eu²⁺ cation is coordinated by two [AsS₄]³⁻ units by edge-sharing and bonded to further two [AsS₄]³⁻ units by corner-sharing. Compound 2 contains a one-dimensional structure with ¹_∞[Dy(AsS₄)₂]³⁻ chains separated by potassium cations. Within each chain, distorted bicapped trigonal prisms of [DyS₈] are linked by slightly distorted [AsS₄]³⁻ tetrahedra. Each Dy³⁺ ion is surrounded by four [AsS₄]³⁻ moieties in an edge-sharing fashion. For compound 3 also a one-dimensional structure with ¹_∞[Nd₀.₆₇(AsS₄)₂]⁴⁻ chains is observed. But the Nd position is only partially occupied and overall every third Nd atom is missing along the chain. This cuts the infinite chains into short dimers containing two bridging [As₄]³⁻ units and four terminal [AsS₄]³⁻ groups. 1 is characterized with UV/vis diffuse reflectance spectroscopy, IR, and Raman spectra.     

Synthesis, crystal structure, and preliminary study of luminescent properties of InTbGe2O7

A new indium terbium germanate InTbGe₂O₇, which is a member of the thortveitite family, was prepared as a polycrystalline powder material by high-temperature solid-state reaction. This new compound crystallizes in the monoclinic system, space group C2/c (No. 15), with unit cell parameters a=6.8818(2) Å, b=8.8774(3) Å, c=9.7892(4) Å, β=101.401(1)°, V=586.25(4) ų and Z=4. Its structure was characterized by Rietveld refinement of powder laboratory X-ray diffraction data. It consists of octahedral sheets that are held together by sheets of isolated Ge₂O₇ diorthogroups composed of two tetrahedra sharing a common vertex. It contains only one octahedral site occupied by In³⁺ and Tb⁺³ cations. The characteristic mirror plane in the thortveitite (Sc₂Si₂O₇) space group (C2/m, No. 12) is not present in this new compound. Besides, in InTbGe₂O₇, the Ge–O–Ge angle bridging two diorthogroups is 156.8(2)° as compared to the one in thortveitite, which is 180°. On the other hand, luminescent properties were observed when it is excited with 376.5 nm wavelength. The luminescence spectrum shows typical transitions from the ⁵D₄ multiplet belonging to the trivalent terbium ion.     

Ba2(VO2)(PO4)(HPO4)·H2O, a New Barium Vanadium(V) Phosphate Hydrate Containing Trigonal Bipyramidal VO5Groups

The hydrothermal synthesis, single crystal structure, and some physical properties of Ba₂(VO₂)(PO₄)(HPO₄)·H₂O, a new barium vanadium(V) phosphate hydrate, are reported. This phase is built up from one-dimensional chains of unusual VO₅trigonal bipyramids and (H)PO₄tetrahedra, fused together via V–O–P linkages. These anionic chains propagate along the polar [010] direction. 11-Coordinate barium cations and water molecules occupy the interchain regions and link the chains together. Structural data for this phase and other known barium vanadium phosphates are briefly compared. Crystal data: Ba₂(VO₂)(PO₄)(HPO₄)·H₂O,M_r=566.57, monoclinic, space groupP2₁(No. 4),a=5.0772(5) Å,b=8.724(2) Å,c=10.806(1) Å,β=90.795(8)°,V=478.6(1) ų,Z=2,R=2.65%,R_w=2.89% [147 parameters, 1893 observed reflections withI>3σ(I)].     

Synthesis, structure characterization and fluorescence property of a new fluoride borate crystal, CdZn2KB2O6F

A new fluoride borate crystal, CdZn₂KB₂O₆F, has been synthesized by flux-supported solid-state reaction. The crystal structure has been determined by single-crystal X-ray diffraction. It crystallizes in the trigonal space group with a=5.0381(6) Å, b=5.0381(6) Å, c=15.1550(19) Å, α=90.00°, β=90.00°, γ=120.00°, Z=2. The crystal represents a new structure type in which ZnBO₃ layers are connected through bridging fluorine and cadmium atoms alternately along the c-axis. K⁺ cations are filled in the intralayer open channels to balance charge. IR and Raman spectra further confirm the crystal structure. Photoluminescent measurement reveals that CdZn₂KB₂O₆F exhibits blue fluorescence at room temperature in the solid-state.     

Syntheses and characterization of two oxoborates, (Pb3O)2(BO3)2MO4 (M=Cr, Mo)

Two oxoborates, (Pb₃O)₂(BO₃)₂MO₄ (M=Cr, Mo), have been prepared by solid-state reactions below 700 °C. Single-crystal XRD analyses showed that the Cr compound crystallizes in the orthorhombic group Pnma with a=6.4160(13) Å, b=11.635(2) Å, c=18.164(4) Å, Z=4 and the Mo analog in the group Cmcm with a=18.446(4) Å, b=6.3557(13) Å, c=11.657(2) Å, Z=4. Both compounds are characterized by one-dimensional chains formed by corner-sharing OPb₄ tetrahedra. BO₃ and CrO₄ (MoO₄) groups are located around the chains to hold them together via Pb–O bonds. The IR spectra further confirmed the presence of BO₃ groups in both structures and UV–vis diffuse reflectance spectra showed band gaps of about 1.8 and 2.9 eV for the Cr and Mo compounds, respectively. Band structure calculations indicated that (Pb₃O)₂(BO₃)₂MoO₄ is a direct semiconductor with the calculated energy gap of about 2.4 eV.     

[{(NiOH)2Mo10O36(PO4)Ti2}n]: a novel chainlike trimetal heteropolyanion based on pseudo-keggin fragments

A new mixed Mo/Ni/Ti heteropoly compound [C₅H₅NH]₅ [(NiOH)₂Mo₁₀O₃₆(PO₄)Ti₂] has been hydrothermally synthesized and structurally determined by the single-crystal X-ray diffraction. Black prismatic crystals crystallize in the monoclinic system, space group P2(1)/n, a=11.2075(2), b=37.8328(5) c=13.0888(1) Å, β=101.4580(10)°, M=2276.13, V=5439.19(13) ų, Z=4. Data were collected on a Siemens SMART CCD diffractometer at 293(2) K in the range of 1.68<θ<25.09° using the ω-scan technique (λ=0.71073 Å R(F)=0.0872 for 9621 reflections). The title compound contains a trimetal heteropolyanion polymer and “trans-titanium”-bridging pseudo-Keggin fragments linked to a chain.