Two tetravalent uranium silicate and germanate crystals with three membered single-ring by molten salt method: K2USi3O9 and Cs2UGe3O9

Two tetravalent uranium silicate and germanate M₂U^IVT₃O₉ (M = K, Cs; T = Si, Ge) crystals were crystalized under inert gas by molten salt flux growth method. K₂USi₃O₉ (1) crystallizes in the monoclinic space group P1₂₁/n1 with lattice parameters a = 7.1076 Å, b = 10.4776 Å, c = 12.2957 Å, γ = 120° and V = 915.67 Å³. Cs₂UGe₃O₉ (2) crystallizes in a hexagonal space group P-6 with lattice constants of a = 7.5138 Å, b = 7.5138 Å, c = 11.0114 Å, γ = 120° and V = 538.38 ų. Bond valence calculations indicate tetravalent uranium in both structures, which contain three-membered single-ring T₃O₉^6? trimers. K₂USi₃O₉ is the first uranium silicate that contains the Si₃O₉^6? trimers.     

Crystal structures and properties of SrLnCuS3 (Ln = La,Pr)

The crystal structures of SrLnCuS₃ (Ln = La, Pr) have been refined using X-ray powder diffraction data and the derivative difference minimization method in the anisotropic approximation for all atoms. The crystals are orthorhombic, space group Pnma, BaLaCuS₃ structural type, unit cell parameters a = 11.2415(1) Å, b = 4.11053(6) Å, c = 11.5990(1) Å, V = 535.97(1) ų (SrLaCuS₃) and a = 11.1171(1) Å, b = 4.09492(6) Å, c = 11.5069(2) Å, V = 523.84(1) ų (SrPrCuS₃). The crystallographic positions of strontium and lanthanides are mixed by 21 and 11%, respectively. The SrLa-S and SrPr-S bond lengths range from 2.969(3) to 3.131(3) Å and from 2.924(2) to 3.056(2) Å, respectively. Distorted CuS₄ tetrahedra form chains running along the b axis. One-capped Sr/LnS₇ trigonal prisms form a three-dimensional structure with channels accommodating copper ions. The temperatures and enthalpies of incongruent melting are, respectively, 1513 K and 18 J/g (SrLaCuS₃) and 1426 K and 34 J/g (SrPrCuS₃). The compounds are IR transparent in the region of 3000–1800 cm^?1.     

Ligand-based luminescence in lead-containing complexes: The effect of conjugated organic ligands on fluorescence

The asymmetrically substituted heterocyclic alkyne 5-(pyridin-3-ylethynyl) picolinate (P3PA) was synthesized via a one-pot Sonogashira coupling. After purification, P3PA was reacted with Pb(NO₃)₂ into the two-dimensional coordination polymer Pb(P3PA)₂(H₂O)₂ (1) under hydrothermal conditions. Coordination polymer 1 crystallizes into the monoclinic space group I2/a, with a = 15.5775(10) Å, b = 5.9949(4) Å, c = 24.8380(16) Å, and β = 90.7500(10)°. In addition, the luminescent fluorene-based ligands, fluorene-9-carboxylate (FCA) and fluorenone-2,7-dicarboxylate (FDCA), were incorporated into hybrid materials via coordination to the lead (II) cation. Coordination polymer Pb(FCA)₂ (2) crystallizes in the monoclinic space group P2₁/c (a = 8.0518(9) Å, b = 25.338(3) Å, c = 10.5842(12) Å, β = 94.913(2)°), and forms a 1-D polymeric chain. Coordination polymer Pb₃(FDCA)₃(H₂O)₃ (3) crystallizes in the triclinic space group P1 (a = 6.6990(5) Å, b = 10.1529(7) Å, c = 13.6935(9) Å, α = 81.884(2)°, β = 87.260(2)°, γ = 84.399(2)°), and forms pillared 3-D layers. These three compounds have been identified via single crystal X-ray diffraction and characterized via powder X-ray diffraction, UV–Vis spectroscopy, and fluorescence spectroscopy.     

New compounds in the cesium sulfobromide rhenium octahedral cluster chemistry: syntheses and crystal structures of Cs4Re6S8Br6 and Cs2Re6S8Br4

The exploration of the CsReSBr system, in order to identify new phases based on octahedral cluster anions, has produced single crystals of Cs₄Re₆S₈Br₆ (1) (trigonal, space group P-6c2, a=9.7825 (3) Å, c=18.7843 (5) Å, V=1556.77 (1) ų, Z=2, density=5.09 g cm⁻³, μ=36.07 mm⁻¹) and Cs₂Re₆S₈Br₄ (2) (monoclinic, space group P2₁/n, a=6.3664 (1) Å, b=18.4483 (4) Å, c=9.3094 (2) Å, β=104.2618 (8)°, V=1059.69 (4) ų, Z=2, density=6.14 g cm⁻³, μ=45.83 mm⁻¹). These two compounds have been obtained by high-temperature solid state route. Their structures have been solved and refined from single crystal X-ray diffraction data. The structure of Cs₄Re₆S₈Br₆ presents isolated anionic cluster units inscribed in a (Cs⁺)₁₂ cuboctahedron and the one of Cs₂Re₆S₈Br₄ exhibits ReS^i-a,a-iRe inter-unit bridges. The framework of the latter presents then a strongly 1-D character.     

K2[Te4O8(OH)10]: synthesis,crystal structure and thermal behavior

Dipotassium octaoxodecahydroxotetratellurate, K₂[Te₄O₈(OH)₁₀], has been prepared hydrothermally in acidic medium under autogenous pressure. It crystallizes in space group P2₁/c of the monoclinic system with Z=2 in a cell of dimensions a=5.592(1) Å, b=8.283(2) Å, c=16.255(3) Å, and β=99.62(3)°. The outstanding feature of the structure is a tetrameric [Te₄O₈(OH)₁₀]^2– anion built up from edge and corner sharing TeO₆ octahedra. These anions and K⁺ cations are held together by electrostatic interactions and by hydrogen bonds. The compound decomposes in two steps at 350 and 420 °C, corresponding to a water and an oxygen loss, respectively, and affording the mixed valence oxide K₂Te^VI₃Te^IVO₁₂.     

Single crystal growth and structural characterization of ternary transition-metal uranium oxides: MnUO4, FeUO4, and NiU2O6

Single crystals of MnUO₄, FeUO₄, and NiU₂O₆ were grown for the first time. The use of chloride fluxes facilitated the crystal growth. MnUO₄, a hexavalent uranium compound, crystallizes in the orthorhombic space group, Imma, with a = 6.6421(19) Å, b = 6.978(2) Å, and c = 6.748(2) Å, and exhibits typical uranyl, UO₂²⁺, coordination. FeUO₄ and NiU₂O₆ contain pentavalent uranium and are structurally related, exhibiting three-dimensional connectivity. FeUO₄ crystallizes in the orthorhombic space group, Pbcn, with a = 4.8844(2) Å, b = 11.9328(5) Å, c = 5.1070(2) Å. NiU₂O₆ crystallizes in the trigonal space group, P321, with a = 9.0148(3) Å, c = 5.0144(3) Å.     

Syntheses,structures and magnetic properties of the alkali oxonickelates(I) A3NiO2 (A = K,Rb, Cs)

New oxonickelates(I), Rb₃NiO₂ and Cs₃NiO₂, were prepared via the azide/nitrate route, starting from stoichiometric mixtures of azides, nitrates and NiO as precursors. The mixtures were heated steadily in a controlled heating regime up to 723 K and annealed at this temperature for 50 h (30 h for cesium compound) in specially designed containers with silver inlays. The crystal structures of Rb₃NiO₂ and Cs₃NiO₂ were solved and refined by X-ray powder methods. Room temperature α-Rb₃NiO₂ (P4₁2₁2, Z = 4, a = 6.2651(2) Å, b = 14.7438(3) Å; R_wp = 6.30%) and high temperature β-Rb₃NiO₂ (at 523 K P4₂/mnm, Z = 2, a = 6.2750(2) Å, b = 7.5088(3) Å; R_wp = 7.85%) were found to be isostructural to room and high temperature α- and β-K₃NiO₂, respectively. Cs₃NiO₂ crystallizes at room temperature isostructural with the β-K₃NiO₂ (P4₂/mnm, Z = 2, a = 6.4336(3) Å, b = 8.0844(4) Å; R_wp = 5.21%). A₃NiO₂ (A = K, Rb, Cs) are paramagnetic in the whole temperature range investigated. The magnetic susceptibility data have been evaluated by the Curie–Weiss law, where the calculated magnetic moments are as expected for a d⁹ system (μ = 1.73–2.20μ_B). Negative values of Weiss constants are indicative for antiferromagnetic interactions in this family of compounds.     

Synthesis,structure and optical properties of new lanthanide-based derivatives Ln2SbS5Br (Ln=La,Ce)

The first bromothioantimonates of cerium and lanthanum, Ce₂SbS₅Br (I), CeLaSbS₅Br (II) and La₂SbS₅Br (III), have been synthesized and characterized. I and III crystallize in the Pnma (n°62) space group while the structure of II was refined in the P2₁2₁2₁ (n°19) space group probably due to an ordering between Ce and La. The cell parameters are: a=8.847(2) Å, b=5.492(1) Å, c=17.697(6) Å, V=859.9(6) ų for I; a=8.9023(9) Å, b=5.5113(6) Å, c=17.809(2) Å, V=873.8(3) ų for II and a=8.905(2) Å, b=5.526(1) Å, c=17.883(3) Å, V=880.0(5) ų for III. These three materials exhibit the same novel structural arrangement with lanthanides surrounded by sulfur and bromine anions in two different LnS₇Br₃ and LnS₈Br units. Some sulfur atoms are engaged in SS bonding dimers while antimony exhibits a SbS₄E coordination (E=lone pair), the characteristics of which hint at a stereo-active 5s² electron pair. The charge balance in the materials is written as Ln^III₂Sb^III(S₂)^–IIS^–II₃Br. The same red color of the three materials rules out the occurrence of the Ce-4f¹→Ce-5d¹ electronic transition usually observed in Ce containing sulfides. In contrast, band structure calculations (TB-LMTO-ASA) assigned the observed absorption threshold around 2.08 eV for the three phases to the existence of a VB→CB electronic transition, i.e. an unpaired S or Br→Sb or paired S charge transfer.     

Synthesis and crystal structure of Fe[(Te1.5Se0.5)O5]Cl,the first iron compound with selenate(IV) and tellurate(IV) groups

During the search for selenium analogues of FeTe₂O₅Cl, the new iron (III) tellurate(IV) selenate(IV) chloride with the composition Fe[(Te_1.5Se_0.5)O₅]Cl was synthesized by chemical vapor transport (CVT) reaction and characterized by TGA-, EDX-,SCXRD-analysis, as well as IR and Raman spectroscopy. It was found that Fe[(Te_1.5Se_0.5)O₅]Cl crystallizes in the monoclinic space group P2₁/c with unitcell parameters a = 5.183(3) Å, b = 15.521(9) Å, c = 7.128(5) Å and β = 107.16(1)°. The crystal structure of Fe[(Te_1.5Se_0.5)O₅]Cl represents a new structure type and contains electroneutral heteropolyhedral layers formed by dimers of the [FeO₅Cl]^8– octahedra, linked via common O-O edges, and mixed [Te₃SeO₁₀]^4- tetramers. Adjacent layers are stacked along the b axis and linked by weak residual bonds. The new compound is stable up to 420 °C. DFT calculations predict Fe[(Te_1.5Se_0.5)O₅]Cl to be a wide-gap semiconductor with the band gap of ca. 2.7 eV.     

Two new organic–inorganic complexes associating the radical anion ABTS·– and the inorganic cation Ca2+: Ca0.55(ABTS)(H2O)x and Ca5(ABTS)6(H2O)29

The synthesis, crystal structure determination and physical properties of two new charge transfer salts containing the azinobisethylbenzothiazoline (ABTS) anion are described. Electrochemical oxidation in water of the diammonium salt of ABTS in presence of calcium chloride yields black single crystals of two new compounds with different morphologies. The needle-like crystals with Ca_0.55(ABTS)(H₂O)_x formula (x depending on the temperature) belong to the monoclinic symmetry, space group C2/c and cell parameters a=21.568(5), b=14.535(5), c=8.0278(17) Å, β=108.32(3)° at room temperature and a=22.180(4), b=14.288(3), c=8.0823(16) Å, β=108.13(3)°, with a lowering of the symmetry, space group Cc, at 200 K. The plate-shaped crystals formulated as Ca₅(ABTS)₆(H₂O)₂₉ belong also to the monoclinic symmetry with P2₁ space group and cell parameters a=11.222(2), b=37.991(8), c=19.327(4) Å, β=106.37(3)° at 200 K. The structure analysis of the first phase shows a one-dimensional character based on the stacking of organic molecules creating channels in which Ca²⁺ cations and water molecules are located. The second phase can be described as an alternation of organic and inorganic layers corresponding to a bidimensional hybrid network. The magnetic and electrical properties will be discussed.     

Synthesis,crystal structure,and magnetic properties of the oxometallates KBaMnO4 and KBaAsO4

Single crystals of KBaMnO₄ and KBaAsO₄ were grown using the hydroflux method and characterized by single crystal X-ray diffraction. Both compounds crystallize in the orthorhombic space group Pnma with a = 7.7795(4) Å, b = 5.8263(3) Å, and c = 10.2851(5) Å for the manganate and a = 7.7773(10) Å, b = 5.8891(8) Å, and c = 10.3104(13) Å for the arsenate. The materials exhibit a three-dimensional crystal structure consisting of isolated MnO₄³⁻ or AsO₄³⁻ tetrahedra, with the charge balance maintained by K⁺ and Ba²⁺. Each tetrahedron is surrounded by six K⁺ and five Ba²⁺, and shares its corner/edge with KO₁₀ polyhedra and corner/edge/face with BaO₉ polyhedra, respectively. The crystal growth, crystal structure and magnetic properties are discussed.     

Crystal structure,electronic structure and electrical conductivity of the antimony selenide BaLaSb2Se6

BaLaSb₂S₆ and BaLaSb₂Se₆ were prepared by heating the elements in the stoichiometric ratio under exclusion of air at 850 °C. Both chalcogenides adopt the KThSb₆Se₆ structure type, crystallizing in the space group P2₁/c (Z = 4) with a = 4.324(3) Å, b = 14.7057(16) Å, c = 15.910(2) Å, β = 92.741(3)°, Z = 4 for the sulfide and a = 4.4173(3) Å, b = 15.333(1) Å, c = 16.816(1) Å, β = 92.545(2)°, Z = 4 for the selenide. The structure of BaLaSb₂Se₆ is composed of ribbons of distorted SbSe₆ octahedra and Se₂^2? pairs. Electronic structure calculations show that the selenide is a semiconductor, in accord with the electrical conductivity measurement.     

The structures of X2[(Mo6Cl8)Cl6]·nH2O,X=NH4, K,Rb, Cs

The title compounds were synthesized from MoCl₂ and the appropriate commercial chlorides and their structures were solved by a combination of single crystal X-ray diffraction analysis and theoretical methods. The NH₄, K and Rb compounds are essentially isostructural, and crystallize in space group Ia (No. 9) with the cell parameters (in Å) a=9.173(1), b=14.986(2), c=17.505(3), β=92.94(2)° (NH₄); a=9.140(4), b=14.852(5), c=17.445(11), β=93.48(6)° (K); a=9.215(1), b=14.941(3), c=17.532(2), β=92.70(1)° (Rb); while the Cs compound crystallizes in space group P2₁/n (No. 14) with the cell dimensions a=9.771(3), b=12.984(4), c=21.535(4), β=90.81(3)°.     

Two coordination polymers of manganese(II) isophthalate and their preparation,structures, and magnetic properties

Two manganese coordination polymers, [Mn₂(ip)₂(dmf)]·dmf (1) and [Mn₄(ip)₄(dmf)₆]·2dmf (2) (ip=isophthalate; dmf=N,N-dimethylformamide), have been synthesized and characterized. X-ray crystal structural data reveal that compound 1 crystallizes in triclinic space group P?1, a=9.716(3) Å, b=12.193(3) Å, c=12.576(3) Å, α=62.19(2)°, β=66.423(17)°, γ=72.72(2)°, Z=2, while compound 2 crystallizes in monoclinic space group Cc, a=19.80(3) Å, b=20.20(2) Å, c=18.01(3) Å, β=108.40(4)°, Z=4. Variable-temperature magnetic susceptibilities of compounds 1 and 2 exhibit overall weak antiferromagnetic coupling between the adjacent Mn(II) ions.     

Crystal structure of the new borate Li3Gd(BO3)2. Comparison with the homologous Na3Ln(BO3)2 (Ln: La,Nd) compounds

The structure of Li₃Gd(BO₃)₂ has been solved by X-ray diffraction study on single crystal. This novel borate crystallizes in the monoclinic system with the P2₁/c space group (Z=4). The cell parameters are respectively equal to a=8.724(2), b=6.425(2), c=10.095(2) Å and β=116.85(2)°. Refinements of 110 parameters using 2924 independent reflections having I>2σ(I) converged to R₁=0.028 (wR₂=0.058). The structure of Li₃Gd(BO₃)₂ is made up of double layers of eightfold coordinated Gd atoms parallel to the (bc) plane. They are linked by respectively three- and four-coordinated boron and lithium atoms. The structure is compared to that of the homologous sodium compounds, Na₃Ln(BO₃)₂ (Ln: La, Nd), in which LnO₈ polyhedra also form a bi-dimensional array.     

Crystal structures of EuLnCuS<Subscript>3</Subscript> (Ln = Nd and Sm)

The compound sulfides EuLnCuS₃ (Ln = Nd and Sm) were obtained for the first time. Their crystal structures were determined from X-ray powder diffraction data. The crystals of both compounds are orthorhombic (space group Pnma). The compound EuNdCuS₃ is isostructural with BaLaCuS₃; the unit cell parameters are a = 11.0438(2) Å, b = 4.0660(1) Å, c = 11.4149(4) Å. The compound EuSmCuS₃ is isostructural with Eu₂CuS₃; the unit cell parameters are a = 10.4202(2) Å, b = 3.9701(1) Å, c = 12.8022(2) Å.     

Synthesis,crystal growth and structure,magnetic and electrical properties of Ba4Ru2FeO10 and Ba4Ru2CoO10

Crystals of Ba₄Ru₂FeO₁₀ and Ba₄Ru₂CoO₁₀ (Cmca, Z = 4, Ba₄Ru₂FeO₁₀: a = 5.7899(1) Å, b = 13.2898(3) Å, c = 13.0098(4) Å, V = 1001.06 Å³; Ba₄Ru₂CoO₁₀: a = 5.7691(2) Å, b = 13.2061(3) Å, c = 12.9755(4) Å, V = 988.57 Å³) were obtained from binary oxides and BaCoO₃ at 1300 °C. Both compounds crystallize isostructural to Ba₄Ru₃O₁₀ with different preference of the 3d metal at the two crystallographic sites of Ru in the parent compound. Ba₄Ru₂FeO₁₀ exhibits a spin-glass like transition at 25 K, while Ba₄Ru₂CoO₁₀ does not show any magnetic order down to 2 K. According to electrical resistivity measurements performed on single crystals both compounds are semiconductors. In contrast to the variable-range hopping of the transport mechanism of Co bearing material, the electrical resistivity of Ba₄Ru₂FeO₁₀ follows an activation law resulting in a band gap of approximately 0.98 eV.     

Syntheses and structures of two new M6Li8(N3)a6 cluster-unit based compounds: Cs4Re6S8(N3)6·H2O and Na2Mo6Br8(N3)6·2H2O

The two new cluster compounds, Cs₄Re₆S₈(N₃)₆·H₂O (1) and Na₂Mo₆Br₈(N₃)₆·2H₂O (2), have been prepared via solution chemistry route, starting from the Cs₄Re₆S₈Br₆CsBr and Mo₆Br₁₂ precursors synthesized by solid state chemistry techniques, and structurally characterized (crystal data: Cs₄Re₆S₈(N₃)₆·H₂O (1): Orthorhombic, space group Pnam, a=10.0651(1) Å, b=15.8856(2) Å, c=20.1714(3) Å, V=3225.2(7) Å³, Z=4, d_calc=4.48 g cm⁻³, μ=27.43 mm⁻¹; Na₂Mo₆Br₈(N₃)₆·2H₂O (2): Orthorhombic, space group Ibam, a=11.5643(3) Å, b=14.3959(5) Å, c=17.0340(7) Å, V=2835.8(2) ų, Z=4, d_calc=3.63 g cm⁻³, μ=13.91 mm⁻¹). Their structures revealed that in both cases, the M₆Lⁱ₈ cluster core remains unchanged in the starting and final compounds whereas the bromine apical ligands (Br^a) are substituted by N₃ azide groups leading to M₆Lⁱ₈(N₃)^a₆ cluster unit. The new Cs₄Re₆S₈(N₃)₆·H₂O is the first example of a compound containing an octahedral rhenium cluster coordinated to azide groups.