Synthesis, crystal structure and optical properties of BiMgVO5

The new vanadate BiMgVO₅ has been prepared and its structure has been determined by single crystal X-ray diffraction: space group P2₁/n, , , , β=107.38(5)°, wR₂=0.0447, R=0.0255. The structure consists of [Mg₂O₁₀] and [Bi₂O₁₀] dimers sharing their corners with [VO₄] tetrahedra. The ranges of bond lengths are 2.129-2.814 Å for Bi-O; 2.035-2.167 Å for Mg-O and 1.684-1.745 Å for V-O. V-O bond lengths determined from Raman band wavenumbers are between 1.679 and 1.747 Å. An emission band overlapping the entire visible region with a maximum around 650 nm is observed.     

Synthesis and single crystal structures of ternary phosphides Li4SrP2 and AAeP (A=Li, Na; Ae=Sr, Ba)

Two new (NaSrP, Li₄SrP₂) and two known (LiSrP, LiBaP) ternary phosphides have been synthesized and characterized using single crystal X-ray diffraction studies. NaSrP crystallizes in the non-centrosymmetric hexagonal space group (#189, a=7.6357(3) Å, c=4.4698(3) Å, V=225.69(2) Å³, Z=3, and R/wR=0.0173/0.0268). NaSrP adopts an ordered Fe₂P structure type. PSr₆ trigonal prisms share trigonal (pinacoid) faces to form 1D chains. Those chains define large channels along the [001] direction through edge-sharing. The channels are filled by chains of PNa₆ face-sharing trigonal prisms. Li₄SrP₂ crystallizes in the rhombohedral space group (#166, a=4.2813(2) Å, c=23.437(2) Å, V=372.04(4) Å³, Z=3, and R/wR=0.0142/0.0222). In contrast to previous reports, LiSrP and LiBaP crystallize in the centrosymmetric hexagonal space group P6₃/mmc (#194, a=4.3674(3) Å, c=7.9802(11) Å, V=131.82(2) Å³, Z=2, and R/wR=0.0099/0.0217 for LiSrP; a=4.5003(2) Å, c=8.6049(7) Å, V=150.92(2) Å³, Z=2, and R/wR=0.0098/0.0210 for LiBaP). Li₄SrP₂, LiSrP, and LiBaP can be described as Li₃P derivatives. Li atoms and P atoms make a graphite-like hexagonal layer, . In LiSrP and LiBaP, Sr or Ba atoms reside between layers to substitute for two Li atoms of Li₃P, while in Li₄SrP₂, Sr substitutes only between every other layer.     

Three-dimensional molecular network, [{Cu(dps)2(SO4)}·3H2O·DMF]n, and its different third-order NLO performance (dps=4,4′-dipyridyl sulfide)

A new three-dimensional non-interpenetrating coordination polymer, [{Cu(dps)₂(SO₄)}·3H₂O·DMF]_n (1) (dps=4,4′-dipyridyl sulfide) was synthesized and structurally characterized. 1 crystallizes in triclinic system, space group P−1 with cell parameters of a=10.9412(1) Å, b=11.8999(1) Å, c=12.5057(1) Å, V=1400.7(3) Å³, Z=2, D_c=1.573 g cm⁻³, F(0 0 0)=686, μ=1.059 mm⁻¹. R₁=0.0436, wR₂=0.1148. In the polymeric architecture, serve as bridging coligands to connect highly puckered [Cu₂(dps)₂]_n frameworks resulting in a 3D motif containing channels for guest molecule inclusion. Quantum chemistry calculation shows that the third-order NLO properties of polymer 1 are controlled by groups and dps ligands, and metal ions have less influence on the third-order NLO properties.     

Sr10[(PO4)5.5(BO4)0.5](BO2): Growth and crystal structure of a strontium phosphate orthoborate metaborate closely related to the apatite-type crystal structure

Single crystals of the strontium phosphate orthoborate metaborate, Sr₁₀[(PO₄)_5.5(BO₄)_0.5](BO₂), were grown from the melt and investigated by X-ray diffraction (space group , No. 147; a=9.7973(8) Å, c=7.3056(8) Å, V=607.29(10) Å³, Z=1). The crystal structure is closely related to apatite and contains linear metaborate groups, [BO₂]⁻ (point group D_∞h, B-O=1.284(11) Å) taking positions within the channels running along the three-fold inversion axis. Strontium sites are found to be fully occupied while [PO₄]³⁻ tetrahedra are partially replaced by [BO₄]⁵⁻ groups.     

Polyoxometalate-based eight-connected self-catenated network and fivefold interpenetrating framework

Two entangled compounds [(bpy)₆Cu^I₆Cl₃(Mo^VW₅O₁₉)] (1) and [(bpy)₇Cu^I₇Cl₂(BW₁₂O₄₀)]·H₂O (2) (bpy=4,4′-bipyridine), have been successfully synthesized under hydrothermal conditions and characterized by element analysis, IR spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy, and single crystal X-ray diffraction analyses. Compound 1 represents the first eight-connected self-penetrating network constructed from cuprous chloride clusters [Cu₆Cl₃] and Lindquist-type polyoxoanions. Compound 2 exhibits an interesting fivefold interpenetrating network consisting of Keggin polyoxoanions and Cu⁺-metal-organic framework. Crystal data of the two compounds are following: 1, triclinic, , a=11.502(2) Å, b=13.069(3) Å, c=13.296(3) Å, α=90.55(3)°, β=113.74(3)°, γ=110.48(3)°, Z=1; 2, triclinic, , a=12.341(3) Å, b=13.119(3) Å, c=15.367(3) Å, α=99.12(3)°, β=90.53(3)°, γ=104.49(3)°, Z=1.     

Crystal chemistry and ion-exchange properties of the layered uranyl iodate K[UO2(IO3)3]

Single crystals of the potassium uranyl iodate, K[UO₂(IO₃)₃] (1), have been grown under mild hydrothermal conditions. The structure of 1 contains two-dimensional sheets extending in the [ab] plane that consist of approximately linear UO₂²⁺ cations bound by iodate anions to yield UO₇ pentagonal bipyramids. There are three crystallographically unique iodate anions, two of which bridge between uranyl cations to create sheets, and one that is monodentate and protrudes in between the layers in cavities. K⁺ cations form long ionic contacts with oxygen atoms from the layers forming an eight-coordinate distorted dodecahedral geometry. These cations join the sheets together. Ion-exchange reactions have been carried out that indicate the selective uptake of Cs⁺ over Na⁺ or K⁺ by 1. Crystallographic data (193 K, MoKα, ): 1, orthorhombic, Pbca, a=11.495(1) Å, b=7.2293(7) Å, c=25.394(2) Å, Z=8, R(F)=1.95% for 146 parameters with 2619 reflections with I>2σ(I).     

Synthesis, structure, magnetic susceptibility and Mössbauer and Raman spectroscopies of the new oxyphosphate Fe0.50TiO(PO4)

A new iron titanyl oxyphosphate Fe_0.50TiO(PO₄) was synthesized by both solid-state reaction and Cu²⁺-Fe²⁺ ion exchange method. The material was then characterized by X-ray diffraction, Mössbauer spectroscopy, magnetic susceptibility measurements and Raman spectroscopy. The crystal structure of the compound was refined, using X-ray powder diffraction data, by Rietveld profile method; it crytallizes in the monoclinic system, space group P2₁/c (No.14), with , , , β=120.36°(1), and Z=4. The volume of the title compound is comparable to those of the M_0.50^IITiO(PO₄) series, where M^II=Mg, Co, Ni and Zn. The framework is built up from [TiO₆] octahedra and [PO₄] tetrahedra. [TiO₆] octahedra are linked together by corners and form infinite chains along the c-axis. Ti atoms are displaced from the center of octahedral units showing an alternating short distance (1.73 Å) and a long one (2.22 Å). These chains are linked together by [PO₄] tetrahedra. Fe²⁺ cations occupy a triangle-based antiprism sharing two faces with two [TiO₆] octahedra. Mössbauer and magnetic measurements show the existence of iron only in divalent state, located exclusively in octahedral sites with high spin configuration (t_2g⁴e_g²). Raman study confirms the existence of Ti-O-Ti chains.     

[Zn(H2PO4)4] clusters and ∞[Zn2(HPO4)3(H2PO4)2] layers in two new zinc phosphates templated by [H2(4-amino-2.2.6.6-tetramethylpiperidine)] cations

Two zinc phosphates (ZnPO), [H₂(N₂C₉H₂₀)]·[Zn(H₂PO₄)₄] (I) and [H₂(N₂C₉H₂₀)]₂·[Zn₂(HPO₄)₃(H₂PO₄)₂]·H₂O (II), are synthesized under hydrothermal conditions using 4-amino-2.2.6.6-tetramethylpiperidine as organic template. I crystallizes in space group with , , , α=92.57(1)°, β=89.76(1)°, γ=102.16(2)°, and Z=2. Its structure, refined to R=0.029 and R_w=0.076 for 4279 independent reflections, consists of [Zn(H₂PO₄)₄]²⁻ clusters held together through strong hydrogen bonds to form pseudo-layers between which the doubly protonated amine molecules are inserted. II is monoclinic, C2, with , , , β=103.72(5)°, and Z=4 (R=0.079, R_w=0.268, 2477 independent reflections). The structure of II consists of _∞[Zn₂(HPO₄)₃(H₂PO₄)₂]⁴⁻ inorganic (2D) layers built up from vertex-sharing [ZnO₄] and [(H₂/H)PO₄] tetrahedra. Organic cations and water molecules ensure the connection between these layers via hydrogen bonds. It is shown that numerous (1D), (2D), e.g., [H₂(N₂C₉H₂₀)]₂·[Zn₂(HPO₄)₃(H₂PO₄)₂]·H₂O, and (3D) (ZnPO) result from the condensation of the [Zn(H₂PO₄)₄]²⁻ clusters.     

Syntheses and crystal structures of three new borates templated by transition-metal complexes in situ

Three new cobalt borate compounds, [Co(DIEN)₂][B₅O₆(OH)₄]₂ (DIEN=diethylenetriamine) (1), [B₅O₇(OH)₃Co(TREN)] (TREN=tris(2-aminoethyl)amine) (2), and [Co₂(TETA)₃][B₅O₆(OH)₄]₄ (TETA=triethylenetetramine) (3) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR, elemental analysis and thermogravimetry. The structures exhibit interesting 3D supramolecular hydrogen-bonded architectures, involving the similar borate polyanion [B₅O_6+n(OH)_4−n]⁽ⁿ⁺¹⁾⁻(n=0 for 1 and 3, and n=1 for 2) and the templating transition metal complexes which are generated in situ under mild solvothermal conditions. Crystal data: 1, monoclinic, space group C2/m (No. 12), , , , β=93.601(4)°, , Z=2; 2, monoclinic, P2₁/c (No. 14), , , , β=99.926(4)°, , Z=4; 3, triclinic, space group P-1 (No. 2), , , , α=77.009(5)°, β=80.095(2)°, γ=82.334(3)°, , Z=2.     

Hydrothermal synthesis and structure determination of the new vanadium molybdenum mixed oxide V1.1Mo0.9O5 from synchrotron X-ray powder diffraction data

A new vanadium molybdenum mixed oxide V_1.1Mo_0.9O₅ [V(V)_0.2V(IV)_0.9Mo(VI)_0.9O₅] has been synthesized, as a pure phase, via hydrothermal methods in the presence of molybdic acid and vanadyl sulfate. Its crystal structure has been solved ab initio from high-resolution powder diffraction data collected at the ESRF beamline ID31. This compound crystallizes in the monoclinic symmetry, space group C2/m, with cell dimensions , , , β=90.625(3)° and Z=2 per formula. The structure consists of double strings of VO₅ square pyramids sharing edges and corners along [100] and [010], and more weakly bound along [001]. In this latter direction, the bond (V,Mo)-O=2.377 Å, while remaining long, leads for the first time to the interpenetration of the apical oxygens of the [(V,Mo)₂O₅]_n layers, resulting in a three-dimensional (3D) structure closely related to R-Nb₂O₅. This structure will be compared to the pure layer structure of V₂O₅ where this bond reaches 2.793 Å.