Synthesis and structure of [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)]·H2O: An expanded open-framework amine-bearing uranyl phosphate

A new open-framework compound, [C₆H₁₄N₂][(UO₂)₄(HPO₄)₂(PO₄)₂(H₂O)]·H₂O, (DUP-1) has been synthesized under mild hydrothermal conditions. The resulting structure consists of diprotonated DABCOH₂²⁺ (C₆H₁₄N₂²⁺) cations and occluded water molecules occupying the channels of a complex uranyl phosphate three-dimensional framework. The anionic lattice contains uranophane-like sheets connected by hydrated pentagonal bipyramidal UO₇ units. [C₆H₁₄N₂][(UO₂)₄(HPO₄)₂(PO₄)₂(H₂O)]·H₂O possesses five crystallographically unique U centers. U(VI) is present here in both six- and seven-coordinate environments. The DABCOH₂²⁺ cations are held within the channels by hydrogen bonds to both two uranyl oxygen atoms and a μ₂-O atom. Crystallographic data (193 K, Mo Kα, λ=0.71073 Å): DUP-1, monoclinic, P2₁/n, a=7.017(1) Å, b=21.966(4) Å, c=17.619(3) Å, β=90.198(3)°, Z=4, R(F)=4.76% for 382 parameters with 6615 reflections with I>2σ(I).     

Synthesis and characterization of hetero-binuclear Co-Rh complexes [CpCoS2C2(B9H10)][Rh(COD)] and [CpCoSe2C2(B10H10)][Rh(COD)]

Two hetero-binuclear complexes [Cp^∗CoS₂C₂(B₉H₁₀)][Rh(COD)] (2a) and [Cp^∗CoSe₂C₂(B₁₀H₁₀)][Rh(COD)] (2b) [Cp^∗ = η⁵-pentamethylcyclopentadienyl, COD = cyclo-octa-1,5-diene (C₈H₁₂)] were synthesized by the reactions of half-sandwich complexes [Cp^∗CoE₂C₂(B₁₀H₁₀)] [E = S (1a), Se (1b)] with low valent transition metal complexes [Rh(COD)(OEt)]₂ and [Rh(COD)(OMe)]₂. Although the reaction conditions are the same, the structures of two products for dithiolato carborane and diselenolato carborane are different. The cage of the carborane in 2a was opened; However, the carborane cage in 2b was intact. Complexes 2a and 2b have been fully characterized by ¹H, ¹¹B NMR and IR spectroscopy, as well as by elemental analyses. The molecular structures of 2a and 2b have been determined by single-crystal X-ray diffraction analyses and strong metal-metal interactions between cobalt and rhodium atoms (2.6260 Å (2a) and 2.7057 Å (2b)) are existent.     

Synthesis and properties of pyrazine-pillared Ag3Mo2O4F7 and AgReO4 layered phases

The new pyrazine-pillared solids, AgReO₄(C₄H₄N₂) (I) and Ag₃Mo₂O₄F₇(C₄H₄N₂)₃ (C₄H₄N₂=pyrazine, pyz) (II), were synthesized by hydrothermal methods at 150 °C and characterized using single crystal X-ray diffraction (I—P2₁/c, No. 14, Z=4, a=7.2238(6) Å, b=7.4940(7) Å, c=15.451(1) Å, β=92.296(4)°; II—P2/n, No. 13, Z=2, a=7.6465(9) Å, b=7.1888(5) Å, c=19.142(2) Å, β=100.284(8)°), thermogravimetric analysis, UV-Vis diffuse reflectance, and photoluminescence measurements. Individual Ag(pyz) chains in I are bonded to three perrhenate ReO₄^- tetrahedra per layer, while each layer in II contains sets of three edge-shared Ag(pyz) chains (π-π stacked) that are edge-shared to four Mo₂O₄F₇^3- dimers. A relatively small interlayer spacing results from the short length of the pyrazine pillars, and which can be removed at just slightly above their preparation temperature, at >150-175 °C, to produce crystalline AgReO₄ for I, and Ag₂MoO₄ and an unidentified product for II. Both pillared solids exhibit strong orange-yellow photoemission, at 575 nm for I and 560 nm for II, arising from electronic excitations across (charge transfer) band gaps of 2.91 and 2.76 eV in each, respectively. Their structures and properties are analyzed with respect to parent ‘organic free’ silver perrhenate and molybdate solids which manifest similar photoemissions, as well as to the calculated electronic band structures.     

New organically templated gallium oxalate-phosphate structures based on Ga4(PO4)4(C2O4) building unit

Five organic-inorganic hybrid gallium oxalate-phosphates, [Ga₂(PO₄)₂(H₂O)(C₂O₄)_0.5](C₃N₂H₁₂)_0.5(H₂O) (1), [Ga₂(PO₄)₂(C₂O₄)_0.5](C₂N₂H₁₀)_0.5(H₂O) (2), [Ga₂(PO₄)₂(C₂O₄)_0.5](C₃N₂H₁₂)_0.5 (3), [Ga₂(PO₄)₂(H₂PO₄)_0.5(C₂O₄)_0.5](C₄N₃H₁₆)_0.5 (H₂O)_1.5 (4) and [Ga_2.5(PO₄)_2.5(H₂O)_1.5(C₂O₄)_0.5](C₄N₃H₁₅)_0.5 (5), have been synthesized by using 1,3-diaminopropane, ethylenediamine and diethylene triamine as structure-directing agents under hydrothermal condition. The structures of 1-5 are based on Ga₄(PO₄)₄(C₂O₄) building unit made up from Ga₂O₈(C₂O₄) oxalate-bridging dimer and alternating PO₄ and GaO₄ tetrahedral units. Compound 1 is layered structure where the building units link together in the same orientation. Corner sharing of these similar layers result in three-dimensional (3-D) structure 2. However, in compound 3, the building units arrange in a wave-like way to generate two types of eight member ring (8MR) channels. Both 4 and 5 contain the layers where the building units have an opposite orientation. Those layers are linked by H₂PO₄ group and Ga(PO₄)(H₂O)₃ cluster, respectively, to form 3-D frameworks with 12MR large pore channels. Compounds 2-5 exhibit intersecting 3-D channels where the protoned amines are located.     

Synthesis and structural characterization of two polymorphs of Fe(2,2′-bpy)(HPO4)(H2PO4)

Two polymorphs of an organic-inorganic hybrid compound, Fe(2,2′-bpy)(HPO₄)(H₂PO₄) (1 and 2) (2,2′-bpy=2,2′-bipyridine), have been synthesized by hydrothermal methods and structurally characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic susceptibility. Crystal data are as follows: Polymorph 1, monoclinic, space group P2₁/n (No. 14), a=10.904(2) Å, b=6.423(1) Å, c=19.314(3) Å, β=101.161(3)°, and Z=4; Polymorph 2, monoclinic, space group P2₁/c (No. 14), a=11.014(1) Å, b=15.872(2) Å, c=8.444(1) Å, β=109.085(3)°, and Z=4. Polymorph 1 adopts a chain structure in which each iron atom is coordinated by two nitrogen atoms from 2,2′-bpy ligand and four phosphate oxygen atoms. These infinite chains are extended into a 3-D supramolecular array via π-π stacking interactions of the lateral 2,2′-bpy ligands. The structure of polymorph 2 consists of the same building units, namely FeO₄N₂ octahedron, HPO₄ and H₂PO₄ tetrahedra, and 2,2′-bpy ligand, which are linked through their vertices forming an undulated sheetlike structure with 4,12 network. Adjacent layers are extended into a 3-D array via π-π stacking interactions of the aromatic groups. Magnetic susceptibility measurement results confirm that the iron atoms in both compounds are present in the +3 oxidation state.     

Metal phosphonates containing pyridyl N-oxide groups: Syntheses of Cd{(2-C5H4NO)CH(OH)PO3}(H2O)2 and Zn{(4-C5H4NO)CH(OH)PO3} with chain and layer structures

This paper reports the syntheses and characterization of two phosphonate compounds Cd{(2-C₅H₄NO)CH(OH)PO₃}(H₂O)₂ (1) and Zn{(4-C₅H₄NO)CH(OH)PO₃} (2) based on hydroxy(2-pyridyl N-oxide)methylphosphonic and hydroxy(4-pyridyl N-oxide)methylphosphonic acids. Compound 1 has a chain structure in which dimers of edge-shared {CdO₆} octahedra are linked by {CPO₃} tetrahedra through corner-sharing. The pyridyl rings reside on the two sides of the inorganic chain. Compound 2 has a layer structure where the inorganic chains made up of corner-sharing {ZnO₄} and {CPO₃} tetrahedra are covalently connected by pyridyl N-oxide groups. Crystal data for 1: triclinic, space group , a=6.834(1) Å, b=7.539(1) Å, c=10.595(2) Å, α=84.628(3)°, β=74.975(4)°, γ=69.953(4)°. For 2: triclinic, space group , a=5.219(1) Å, b=8.808(2) Å, c=9.270(2) Å, α=105.618(5)°, β=95.179(4)°, γ=94.699(4)°.     

New binuclear vanadium(III) and (IV) squarate species: synthesis, structure and characterization of [V(OH)(H2O)2(C4O4)]2·2H2O and (NH4)[(VO)2(OH)(C4O4)2(H2O)3]·3H2O

Two new vanadium squarates have been synthesized, characterized by infrared and thermal behavior and their structures determined by single crystal X-ray diffraction. Both structures are made of discrete, binuclear vanadium entity but in 1, [V(OH)(H₂O)₂(C₄O₄)]₂·2H₂O the vanadium atom is trivalent and the entity is neutral while in 2, (NH₄)[(VO)₂(OH)(C₄O₄)₂(H₂O)₃]·3H₂O, the vanadium atom is tetravalent and the entity is negatively charged, balanced by the presence of one ammonium ion. Both molecular anions are bridged by two terminal μ₂ squarate ligands. 1 crystallizes in the triclinic system, space group P-1, with lattice constants a=7.5112(10) Å, b=7.5603(8) Å, c=8.2185(8) Å, α=106.904(8)°, β=94.510(10)°, γ=113.984(9)° while 2 crystallizes in the monoclinic system, space group C2/c, with a=14.9340(15) Å, b=6.4900(9) Å, c=17.9590(19) Å and β=97.927(12)°. From the magnetic point of view, V(III) binuclear species show ferromagnetic interactions at low temperatures. However, no anomalies pointing to magnetic ordering are observed down to 2 K.     

[Co(en)3][In3(H2PO4)6(HPO4)3]·H2O: A new layered indium phosphate templated by cobalt complex

A new layered indium phosphate [Co(en)₃][In₃(H₂PO₄)₆(HPO₄)₃]·H₂O (1) has been synthesized solvothermally by using a racemic mix of chiral metal complex Co(en)₃Cl₃ as a template. Its structure is determined by single-crystal X-ray diffraction analysis and further characterized by X-ray powder diffraction, ICP, NMR and TG analyses. The inorganic layer is built up by alternation of In-centred octahedra (InO₆) and P-centered tetrahedra (PO₃(OH), PO₂(OH)₂, PO₂(=O)(OH) and PO(=O)(OH)₂) forming a 4.12-net. The metal complex cations locate in the interlayer region and interact with the host network through H-bonds. It is the first indium phosphate compound templated by a transition-metal complex and is isostructural with GaPO-CJ14. Crystal data: 1, monoclinic, space group P2₁/m (No. 11), a=9.1700(18) Å, b=22.6923(5) Å, c=9.9116(2) Å, β=107.87(3)°, Z=4, R_1[I>2σ(I)]=0.0287 and wR_{2(all data)}=0.0939.     

(C6H17N3)[Zn4(PO4)2(HPO3)2]: a new layered zinc phosphate-phosphite templated by 1-(2-Aminoethyl) piperazine

Employing 1-(2-Aminoethyl) piperazine as a template, a new organically templated layered zinc phosphate-phosphite (C₆H₁₇N₃)[Zn₄(PO₄)₂(HPO₃)₂] has been prepared hydrothermally. Single-crystal X-ray diffraction analysis shows that it crystallizes in the monoclinic space group Cc with a=5.3272(11) Å, b=17.146(3) Å, c=22.071(4) Å, β=94.58(3)°, V=2009.5(7) Å³, Z=4, R₁=0.0201 (I>2σ(I)) and wR₂=0.0812 (all data). The inorganic network is based on strictly alternating ZnO₄ tetrahedral units and P-centered units including PO₄ tetrahedra and HPO₃ pseudo-pyramids forming a double layered structure that contains columns of double six-membered rings. The diprotonated 1-(2-Aminoethyl) piperazine molecules reside in the interlayer region and interact with the inorganic network through H-bonds.     

Combinatorial topology of uranyl molybdate sheets: syntheses and crystal structures of (C6H14N2)3[(UO2)5(MoO4)8](H2O)4 and (C2H10N2)[(UO2)(MoO4)2]

Two new mixed organic-inorganic uranyl molybdates, (C₆H₁₄N₂)₃[(UO₂)₅(MoO₄)₈](H₂O)₄ (1) and (C₂H₁₀N₂)[(UO₂)(MoO₄)₂] (2), have been obtained by hydrothermal methods. The structure of 1 [triclinic, , Z=1, a=11.8557(9), b=11.8702(9), c=12.6746(9) Å, α=96.734(2)°, β=91.107(2)°, γ=110.193(2)°, V=1659.1(2) Å] has been solved by direct methods and refined on the basis of F² for all unique reflections to R1=0.058, which was calculated for the 5642 unique observed reflections (|F_o|?4σ_F). The structure contains topologically novel sheets of uranyl square bipyramids, uranyl pentagonal bipyramids, and MoO₄ tetrahedra, with composition [(UO₂)₅(MoO₄)₈]⁶⁻, that are parallel to (−101). H₂O groups and 1,4-diazabicyclo [2.2.2]-octane (DABCO) molecules are located in the interlayer, where they provide linkage of the sheets. The structure of 2 [triclinic, , Z=2, a=8.4004(4), b=11.2600(5), c=13.1239(6) Å, α=86.112(1)°, β=86.434(1)°, γ=76.544(1)°, V=1203.14(10) Å] has been solved by direct methods and refined on the basis of F² for all unique reflections to R1=0.043, which was calculated for 5491 unique observed reflections (|F_o|?4σ_F). The structure contains topologically novel sheets of uranyl pentagonal bipyramids and MoO₄ tetrahedra, with composition [(UO₂)(MoO₄)₂]²⁻, that are parallel to (110). Ethylenediamine molecules are located in the interlayer, where they provide linkage of the sheets. All known topologies of uranyl molybdate sheets of corner-sharing U and Mo polyhedra can be described by their nodal representations (representations as graphs in which U and Mo polyhedra are given as black and white vertices, respectively). Each topology can be derived from a simple black-and-white graph of six-connected black vertices and three-connected white vertices by deleting some of its segments and white vertices.     

Synthesis, crystal structure and NLO property of a nonmetal pentaborate [C6H13N2][B5O6(OH)4]

A nonmetal pentaborate [C₆H₁₃N₂][B₅O₆(OH)₄] (1) has been synthesized by 1,4-diazabicyclo[2.2.2] octane (DABCO) and boric acid, and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis, and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic system with space group Cc (no. 9), a=10.205(2) Å, b=14.143(3) Å, c=11.003(2) Å, β=113.97(3)°, V=1451.1(5) Å³, Z=4. The anionic units, [B₅O₆(OH)₄]⁻, are interlinked via hydrogen bonding to form a three-dimensional (3D) supramolecular network containing large channels, in which the protonated [C₆H₁₃N₂]⁺ cations are located. Second-harmonic generation (SHG) measurements on the powder samples reveal that 1 exhibits SHG efficiency approximately 0.9 times that of potassium dihydrogen phosphate (KDP).     

Synthesis and Structure of a New Layered Zincophosphate Zn6(PO4)5(HPO4)·C8N5H28·5H2O, Intercalated with Quintuply Protonated Tetraethylenepentamine

A new two-dimensional zinc phosphate Zn₆(PO₄)₅(HPO₄)·C₈N₅H₂₈·5H₂O has been synthesized hydrothermally using tetraethylenepentamine (TEPA) as structure-directing agent and its structure was determined by means of single-crystal X-ray diffraction. The title compound crystallizes in the orthorhombic system, space group Pca2₁ (No.29) with lattice parameters a=18.6286(12) Å, b=8.0804(5) Å, c=22.5019(15) Å, V= 3387.1(4) ų, Z=4, R₁=0.0389 and wR₂=0.0862 [4042 observed reflections with I>2σ(I)]. The structure involves a network of ZnO₄, PO₄, and PO₃(OH) tetrahedra forming macroanionic inorganic layers with eight-membered apertures. The charge compensation is achieved by the quintuply protonated TEPA molecule in interlamellar space, which interact with the inorganic layers via hydrogen bonding.     

Hydrothermal synthesis, crystal structure, thermal behavior and spectroscopic and magnetic properties of two new organically templated fluoro-vanadyl-hydrogenarsenates: (R)0.5[(VO)(HAsO4)F] (R: Ethylenediammonium and piperazinium)

Two new fluoro-vanadyl-hydrogenarsenate compounds templated by ethylenediamine and piperazine with formula, (C₂N₂H₁₀)_0.5[(VO)(HAsO₄)F] (1) and (C₄N₂H₁₂)_0.5[(VO)(HAsO₄)F] (2), respectively, have been synthesized by using mild hydrothermal conditions under autogenous pressure. The crystal structures have been solved from single-crystal X-ray diffraction data. The phases crystallize in the P2₁/c monoclinic space group with the unit-cell parameters a=7.8634(4) Å, b=7.7658(4) Å, c=10.4195(6) Å, β=101.524(5)° for compound (1) and a=6.301(1) Å, b=10.244(1) Å, c=10.248(1) Å and β=95.225(1)° for compound (2). These phases exhibit a layered inorganic framework. In both cases, the structure is built from secondary building units (SBU) which are formed by [V₂O₈F₂] edge-shared dimeric vanadyl octahedra, connected by the vertices to two hydrogenarsenate tetrahedra. The repetition of this SBU unit originates sheets along the [1 0 0] direction. The ethylenediammonium and piperazinium cations are located inside the interlayer space. The limit of thermal stability for compounds (1) and (2) is, approximately, 250 and 230 °C, respectively. Near this temperature, both phases loose their organic cations and the fluoride anions. The diffuse reflectance spectra confirm the presence of vanadyl ions, in which the vanadium(IV) cations have a d¹ electronic configuration in a slightly distorted octahedral environment. ESR spectra of both phases are isotropic with mean g-values of 1.93 and 1.96 for ethylendiamine and piperazine phases, respectively. Magnetic measurements for (1) and (2) indicate the existence of antiferromagnetic exchange couplings.     

[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.     

Solvothermal synthesis and characterisation of new one-dimensional indium and gallium sulphides: [C10N4H26]0.5[InS2] and [C10N4H26]0.5[GaS2]

Two new main group metal sulphides, [C₁₀N₄H₂₆]_0.5[InS₂] (1) and [C₁₀N₄H₂₆]_0.5[GaS₂] (2) have been prepared solvothermally in the presence of 1,4-bis(3-aminopropyl)piperazine and their crystal structures determined by single-crystal X-ray diffraction. Both compounds are isostructural and crystallise in the monoclinic space group P2₁/n (Z=4), with a=6.5628(5), b=11.2008(9), c=12.6611(9) Å and β=94.410(4)° (wR=0.035) for compound (1) and a=6.1094(5), b=11.2469(9), c=12.7064(10) Å and β=94.313(4)° (wR=0.021) for compound (2). The structure of [C₁₀N₄H₂₆]_0.5[MS₂] (M=In,Ga) consists of one-dimensional [MS₂]⁻ chains which run parallel to the crystallographic a axis and are separated by diprotonated amine molecules. These materials represent the first example of solvothermally prepared one-dimensional gallium and indium sulphides.     

A sodium gallophosphate with an original tunnel structure: NaGa2(OH)(PO4)2

A new sodium gallophosphate, NaGa₂(OH)(PO₄)₂, has been obtained by hydrothermal synthesis under autogeneous pressure at 473 K. It crystallizes in the P2₁/n space group with the cell parameters a=8.9675(8) Å, b=8.9732(5) Å, c=9.2855(7) Å, β=114.812(6)°, V=678.2 Å³ (Z=4). In its original three-dimensional framework, monophosphate groups share their apices with [Ga₄O₁₆(OH)₂] tetrameric units, which are built from two GaO₅(OH) octahedra and two GaO₄(OH) trigonal bipyramids. The sodium cations are located in tunnels running along a, whereas the tunnels running along b are empty.     

A new sodium hydroxygallophosphate containing tetrameric gallium units: Na3[Ga4O(OH)(H2O)(PO4)4]·H2O

A new sodium hydroxygallophosphate, Na₃Ga₄O(OH)(H₂O)(PO₄)₄·H₂O, has been prepared by hydrothermal synthesis. Its structure has been determined from a single-crystal X-ray diffraction study. It crystallizes in the P2₁/c space group with the cell parameters a=9.445(2) Å, b=9.028(1) Å, c=19.209(3) Å, β=102.08(2), V=1603.4(4) Å³. Its three-dimensional framework can be described from PO₄ monophosphate groups sharing their apices with original Ga₄O₁₆(OH)(H₂O) tetrameric building units, which result from the assembly of one GaO₄ tetrahedron, one GaO₅ trigonal bipyramid and two octahedra: GaO₅(OH) and GaO₄(OH)(H₂O). The sodium cations and one water molecule are located in tunnels running along b.     

New Gallium Phosphate Frameworks Containing 1,4-Diaminobutane and 1,5-Diaminopentane: [NH3(CH2)xNH3][Ga4(PO4)4(HPO4)] and [NH3(CH2)xNH3][Ga(PO4)(HPO4)] (x=4 and 5)

Two new gallium phosphates, [NH₃(CH₂)₄NH₃][Ga₄(PO₄)₄ (HPO₄)] (I) and [NH₃(CH₂)₄NH₃][Ga(PO₄)(HPO₄)] (II), have been synthesized under solvothermal conditions in the presence of 1,4-diaminobutane and their structures determined using room-temperature single-crystal X-ray diffraction data. Compound (I) (M_r=844.90, triclinic, space group P-1, a=9.3619(3), b=10.1158(3) and c=12.6456(5) Å, α=98.485(1), β=107.018(2) and γ=105.424(1)°; V=1070.39 ų, Z=2, R=3.68% and R_w=4.40% for 2918 observed data [I>3(σ(I))]) consists of GaO₄ and PO₄ tetrahedra and GaO₅ trigonal bipyramids linked to generate an open three-dimensional framework containing 4-, 6-, 8-, and 12-membered rings of alternating Ga- and P-based polyhedra. 1,4-Diaminobutane dications are located in channels bounded by the 12-membered rings in the two-dimensional pore network and are held to the framework by hydrogen bonding. Compound (II) (M_r=350.84, monoclinic, space group P2₁/c, a=4.8922(1), b=18.3638(6) and c=13.7468(5) Å, β=94.581(1)°; V=1227.76 ų, Z=4, R=2.95% and R_w=3.37% for 2050 observed data [I>3(σ(I))]) contains chains of edge-sharing 4-membered rings of alternating GaO₄ and PO₄ tetrahedra constituting a backbone from which hang ‘pendant’ PO₃(OH) groups. Hydrogen bonding between the GaPO framework and the diamine dications holds the structure together. A previously reported phase, [NH₃(CH₂)₄NH₃][Ga₄(PO₄)₄(HPO₄)] (V), structurally related but distinct from its stoichiometric equivalent, (I), has been prepared as a pure phase by this method. Two further materials, [NH₃(CH₂)₅NH₃][Ga₄(PO₄)₄(HPO₄)] (III) (tricli- nic, lattice parameters from PXD: a=9.3565(4), b=5.0156(2) and c=12.7065(4) Å, α=96.612(3), β=102.747(4) and γ=105.277(3)°) and [NH₃(CH₂)₅NH₃][Ga(PO₄)(HPO₄)] (IV) (M_r=364.86, monoclinic, space group P2₁/n, a=4.9239(2), b=13.2843(4) and c=19.5339(7) Å, β=96.858(1)°; V=1268.58 ų, Z=4, R=3.74% and R_w=4.44% for 2224 observed room-temperature data [I>3(σ(I))]), were also prepared under similar conditions in the presence of 1,5-diaminopentane. (III) and (IV) are structurally related to, yet distinct from (I) and (II) respectively.     

Two isotypic diphosphates LiM2H3(P2O7)2 (M=Ni, Co) containing ferromagnetic zigzag MO6 chains

Two new isotypic phosphates LiNi₂H₃(P₂O₇)₂ (1) and LiCo₂H₃(P₂O₇)₂ (2) have been hydrothermally synthesized and structurally characterized by the single-crystal X-ray diffraction technique. They crystallize in the monoclinic space group C2/c with the lattice: a=10.925(2) Å, b=12.774(3) Å, c=8.8833(18) Å, β=123.20(3)° for 1 and a=10.999(2) Å, b=12.863(3) Å, c=8.9419(18) Å, β=123.00(3)° for 2. The transition metal atoms are octahedrally coordinated, whereas the lithium and phosphorus atoms are all tetrahedrally coordinated. As the lithium-induced derivatives of MH₂P₂O₇ (M=Ni, Co), 1 and 2 possess the same structure with MH₂P₂O₇ in terms of topology, comprising the MO₆ zigzag chains and P₂O₇ as the interchain groups. The magnetisms of 1 and 2 could be interpreted by adopting a quasi-one-dimensional (1D) zigzag chain model as that in their parent compounds: both 1 and 2 have ferromagnetic (FM) NiO₆/CoO₆ chains; 1 shows a FM cluster glass behavior at low temperatures, which is originated from the possible antiferromagnetic (AFM) next-nearest-neighbour intrachain interactions; 2 shows a AFM ordering at T_N=2.6 K and a metamagnetic transition at H_C=4.2 kOe at 1.8 K.     

Hydrothermal syntheses and structures of the uranyl tellurates AgUO2(HTeO5) and Pb2UO2(TeO6)

Two uranyl tellurates, AgUO₂(HTeO₅) (1) and Pb₂UO₂(TeO₆) (2), were synthesized under hydrothermal conditions and were structurally, chemically, and spectroscopically characterized. 1 crystallizes in space group Pbca, a=7.085(2) Å, b=11.986(3) Å, c=13.913(4) Å, V=1181.5(5) Å³, Z=8; 2 is in P2(1)/c, a=5.742(1) Å, b=7.789(2) Å, c=7.928(2) Å, V=90.703(2) Å³, and Z=2. These are the first structures reported for uranyl compounds containing tellurate. The U⁶⁺ cations are present as (UO₂)²⁺ uranyl ions that are coordinated by O atoms to give pentagonal and square bipyramids in compounds 1 and 2, respectively. The structural unit in 1 is a sheet consisting of chains of edge-sharing uranyl pentagonal bipyramids that are one bipyramid wide, linked through the dimers of TeO₆ octahedra. In 2, uranyl square bipyramids share each of their equatorial vertices with different TeO₆ octahedra, giving a sheet with the autunite-type topology. Sheets in 1 and 2 are connected through the low-valence cations that are located in the interlayer region. The structures of 1 and 2 are compared to those of uranyl compounds containing octahedrally coordinated cations.