Synthese und Kristallstruktur von K2(HSO4)(H2PO4), K4(HSO4)3(H2PO4) und Na(HSO4)(H3PO4)

Synthesis and Crystal Structure of K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄), and Na(HSO₄)(H₃PO₄) Mixed hydrogen sulfate phosphates K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄) and Na(HSO₄)(H₃PO₄) were synthesized and characterized by X‐ray single crystal analysis. In case of K₂(HSO₄)(H₂PO₄) neutron powder diffraction was used additionally. For this compound an unknown supercell was found. According to X‐ray crystal structure analysis, the compounds have the following crystal data: K₂(HSO₄)(H₂PO₄) (T = 298 K), monoclinic, space group P 2₁/c, a = 11.150(4) Å, b = 7.371(2) Å, c = 9.436(3) Å, β = 92.29(3)°, V = 774.9(4) ų, Z = 4, R₁ = 0.039; K₄(HSO₄)₃(H₂PO₄) (T = 298 K), triclinic, space group P 1, a = 7.217(8) Å, b = 7.521(9) Å, c = 7.574(8) Å, α = 71.52(1)°, β = 88.28(1)°, γ = 86.20(1)°, V = 389.1(8)ų, Z = 1, R₁ = 0.031; Na(HSO₄)(H₃PO₄) (T = 298 K), monoclinic, space group P 2₁, a = 5.449(1) Å, b = 6.832(1) Å, c = 8.718(2) Å, β = 95.88(3)°, V = 322.8(1) ų, Z = 2, R₁ = 0,032. The metal atoms are coordinated by 8 or 9 oxygen atoms. The structure of K₂(HSO₄)(H₂PO₄) is characterized by hydrogen bonded chains of mixed H_nS/PO₄^– tetrahedra. In the structure of K₄(HSO₄)₃(H₂PO₄), there are dimers of H_nS/PO₄^– tetrahedra, which are further connected to chains. Additional HSO₄^– tetrahedra are linked to these chains. In the structure of Na(HSO₄)(H₃PO₄) the HSO₄^– tetrahedra and H₃PO₄ molecules form layers by hydrogen bonds.     

Doppelkettenstruktur von (pipzH2)[MnF2(HPO4)(H2O)](H2PO4)

By adding piperazine to a hydrofluoric and phosphoric acid solution of Manganese(III) fluoride, the fluoride phosphate (pipzH₂)[MnF₂(HPO₄)(H₂O)](H₂PO₄) can be crystallized. Its structure is built by piperazinium(2+) cations, (H₂PO₄)^? anions, and an anionic double‐chain of [HPO₄] tetrahedra and [MnO₃F₂(H₂O)] octahedra. The structure is triclinic, space group P , Z = 2, a = 622.97(4), b = 923.46(6), c = 1183.62(7) pm, α = 98.343(6)°, β = 100.747(7)°, γ = 107.642(5)°, R = 0.0289. It is worth noting that a ferrodistortive Jahn‐Teller order is observed with [MnO₃F₂(H₂O)] octahedra strongly elongated along the F–Mn–OH₂ axes perpendicular to the chain plane. The structure is stabilized by very strong hydrogen bonds.     

Pseudo‐Isomerie durch unterschiedliche Jahn‐Teller‐Ordnung: Die Kristallstrukturen des Hemihydrats und des Monohydrats von (pyH)[MnF(H2PO4)(HPO4)]

Pseudo‐Isomerism by Different Jahn‐Teller Ordering: Crystal Structures of the Hemihydrate and the Monohydrate of (pyH)[MnF(H₂PO₄)(HPO₄)] With pyridinium counter cations (pyH⁺) the Mn^III fluoride phosphate anion [MnF(H₂PO₄)(HPO₄)]^— can be stabilized. It forms a chain structure with Mn³⁺ ions bridged by a fluoride ion and two bidentate phosphate groups. Under sleightly differing conditions either the hemihydrate (pyH)[MnF(H₂PO₄)(HPO₄)]·0.5H₂O ( 1 ) or the monohydrate (pyH)[MnF(H₂PO₄)(HPO₄)]·H₂O ( 2 ) is formed. The hemihydrate 1 crystallizes monoclinic in space group P2₁/n, Z = 8, a = 7.295(1), b = 17.052(2), c = 18.512(3) Å, β = 100.78(1)°, R = 0.033, the monohydrate triclinic in space group P1¯, Z = 2, a = 7.374(1), b = 8.628(1), c = 10.329(1) Å, α = 83.658(8)°, β = 77.833(9)°, γ = 68.544(8)°, R = 0.025. Whereas the topology of the chain anions is identical in both structures, the Jahn‐Teller effect is expressed in different ordering patterns: in 1 antiferrodistortive ordering of [MnF₂O₄] octahedra is observed, with alternating elongation of an F—Mn—F‐axis or a O—Mn—O‐axis, respectively. This leads to asymmetrical Mn—F—Mn‐bridges. In 2 ferrodistortive ordering is found, with elongation of all octahedra along the F—Mn—F‐axis. Thus, symmetrical bridges are formed with long Mn—F distances. This unusual pseudo‐isomerism is attributed to the differing influence of inter‐chain hydrogen bonds.     

Preparation,Single Crystal Structure Analysis,and Thermal Behaviour of the Acidic Mercury(I) Phosphate (Hg2)2(H2PO4)(PO4)

Yellowish single crystals of acidic mercury(I) phosphate (Hg₂)₂(H₂PO₄)(PO₄) were obtained at 200 °C under hydrothermal conditions in 32% HF from a starting complex of microcrystalline (Hg₂)₂P₂O₇. Refinement of single crystal data converged at a conventional residual R[F² > 2σ(F²)] = 3.8% (C2/c, Z = 8, a = 9.597(2) Å, b = 12.673(2) Å, c = 7.976(1) Å, β = 110.91(1)°, V = 906.2(2) ų, 1426 independent reflections > 2σ out of 4147 reflections, 66 variables). The crystal structure consists of Hg₂²⁺‐dumbbells and discrete phosphate groups H₂PO₄^– and PO₄^3–. The Hg₂²⁺ pairs are built of two crystallographically independent Hg atoms with a distance d(Hg1–Hg2) = 2.5240(6) Å. The oxygen coordination sphere around the mercury atoms is asymmetric with three O atoms for Hg1 and four O atoms for Hg2. The oxygen atoms belong to the different PO₄ tetrahedra, which in case of H₂PO₄‐groups are connected by hydrogen bonding. Upon heating over 230 °C, (Hg₂)₂(H₂PO₄)(PO₄) condenses to (Hg₂)₂P₂O₇, which in turn disproportionates at higher temperatures into Hg₂P₂O₇ and elemental mercury.     

The Oxidation of Heterogeneous Tl/Ni/P‐Alloys — Preparation and Crystal Structures of the Thallium Nickel Phosphates TlNi4(PO4)3, Tl4Ni7(PO4)6, and Tl2Ni4(P2O7)(PO4)2

Single crystals of the first anhydrous thallium nickel phosphates were prepared by reaction of heterogeneous Tl/Ni/P alloys with oxygen. TlNi₄(PO₄)₃ (pale‐yellow, orthorhombic, space group Cmc2₁, a = 6.441(2)Å, b = 16.410(4)Å, c = 9.624(2)Å, Z = 4) crystallizes with a structure closely related to that of NaNi₄(PO₄)₃. Tl₄Ni₇(PO₄)₆ (yellow‐brown, monoclinic, space group Cm, a = 10.711(1)Å, b = 14.275(2)Å, c = 6.688(2)Å, β = 103.50(2)°, Z = 8) is isotypic with Na₄Ni₇(PO₄)₆, and Tl₂Ni₄(P₂O₇)(PO₄)₂ (brown, monoclinic, space group C2/c, a = 10.389(2)Å, b = 13.888(16)Å, c = 18.198(3)Å, β = 103.1(2)°, Z = 8) adopts the K₂Ni₄(P₂O₇)(PO₄)₂ structure. Tl₂Ni₄(P₂O₇)(PO₄)₂ could also be prepared in nearly single phase form by reaction of Tl₂CO₃, NiO, and (NH₄)₂HPO₄.     

Potassium gallium hydrogenphosphate fluoride,K2Ga[H(HPO4)2]F2

Hydrothermally synthesized dipotassium gallium {hydrogen bis[hydrogenphosphate(V)]} difluoride, K₂Ga[H(HPO₄)₂]F₂, is isotypic with K₂Fe[H(HPO₄)₂]F₂. The main features of the structure are ([Ga{H(HPO₄)₂}F₂]²⁻)_n columns consisting of centrosymmetric Ga(F₂O₄) octahedra [average Ga—O = 1.966 (3) Å and Ga—F = 1.9076 (6) Å] stacked above two HPO₄ tetrahedra [average P—O = 1.54 (2) Å] sharing two O‐atom vertices. The charge‐balancing seven‐coordinate K⁺ cations [average K—O,F = 2.76 (2) Å] lie in the intercolumn space, stabilizing a three‐dimensional structure. Strong [O...O = 2.4184 (11) Å] and medium [O...F = 2.6151 (10) Å] hydrogen bonds further reinforce the connections between adjacent columns.     

Oxyfluorinated compounds with an open structure XVI. Synthesis,structure determination and magnetic properties of Fe4F3(PO4)(HPO4)4(H2O)4(N2C3H12) [ULM-15]

Fe₄F₃(PO₄)(HPO₄)₄(H₂O)₄(N₂C₃H₁₂) (labelled ULM-15) was prepared hydrothermally (7 days, 453 K, autogenous pressure) in the presence of 1,3-diaminopropane as organic template. Its structure was determined by single crystal X-ray diffraction. ULM-15 is monoclinic (Space group C2/c (no 15)) with lattice parameters a = 24.176(1) , b = 14.558(1) , c = 7.186(1) , β = 102.3(1)°, V = 2470.8(3) ³, Z = 4. Its three-dimensional framework is constituted from corner-sharing FeX₆ (X = O, F, H₂O) octahedra and tetrahedral PO₄ and HPO₄ groups. The structure presents trans-chains of FeO₄F₂ octahedra related to ferric dimers [Fe₂O₈F₂(H₂O)₂] by tetrahedral units. They delimit 16-membered rings channels along [001] in which the diprotonated amines are inserted. ULM-15 shows 3D antiferromagnetic behaviour below T_N ≈ 22 K.     

Investigation of mixed alkaline earth phosphates. Synthesis and crystal structure of CaBa(HPO4)2: A new mixed alkaline earth hydrogenmonophosphate

Hydrothermal synthesis, IR characterization and X-ray single-crystal structure are reported for CaBa(HPO₄)₂. It crystallizes in the monoclinic system, space group P2₁/a (N∘14) with a = 9.470(2) Å, b = 7.930(1) Å, c = 9.865(1) Å, β = 115.78(1)°, V = 667.1(2) ų and Z = 4. The refinement of data leads to R = 0.0331 for 1131 observed reflections [I > 4σ(I)]. The crystal structure of CaBa(HPO₄)₂ is built up from corner-and/or edge-sharing BaO₉ polyhedra, CaO₇ pentagonal bipyramids and (H)PO₄ tetrahedra giving rise to a three-dimensional network. The HPO₄²⁻ groups are located in layers parallel to the ab plane at z ~ 0 and z ~ 1/2. Interleaved barium and calcium cations ensure the cohesion between these sheets. Hydrogen bonds contribute to the stability of the structure.     

Preparation and Structure Determination of SrMn2(PO4)2 and Redetermination of b ′‐Mn3(PO4)2

Pale rose single crystals of SrMn₂(PO₄)₂ were obtained from a mixture of SrCl₂ · 6 H₂O, Mn(CH₃COO)₂, and (NH₄)₂HPO₄ after thermal decomposition and finally melting at 1100 °C. The new crystal structure of strontium manganese orthophosphate [P‐1, Z = 4, a = 8.860(6) Å, b = 9.054(6) Å, c = 10.260(7) Å, α = 124.27(5)°, β = 90.23(5)°, γ = 90.26(6)°, 4220 independent reflections, R1 = 0.034, wR2 = 0.046] might be described as hexagonal close‐packing of phosphate groups. The octahedral, tetrahedral and trigonal‐bipyramidal voids within this [PO₄] packing provide different positions for 8‐ and 10‐fold [SrO_x] and distorted octahedral [MnO₆] coordination according to a formulation Mn Mn Mn Sr (PO₄)₄. Single crystals of β′‐Mn₃(PO₄)₂ (pale rose) were grown by chemical vapour transport (850 °C → 800 °C, P/I mixtures as transport agent). The unit cell of β′‐Mn₃(PO₄)₂ [P2₁/c, Z = 12, a = 8.948(2) Å, b = 10.050(2) Å, c = 24.084(2) Å, β = 120.50°, 2953 independent reflections, R1 = 0.0314, wR2 = 0.095] contains 9 independent Mn²⁺. The reinvestigation of the crystal structure led to distinctly better agreement factors and significantly reduced standard deviations for the interatomic distances.     

Synthesis,Magnetism, and Crystal Structure of Li2Fe[(PO4)(HPO4)] and its Hydrogen Position Refinement

Lithium iron(III) monophosphate-monohydrogen-monophosphate, Li₂Fe[(PO₄)(HPO₄)], was synthesized under mild hydrothermal conditions and its crystal structure was determined by single crystal X-ray diffraction methods. Crystallographic data: monoclinic, P12₁/n1 (no. 14), a = 4.8142(2) Å, b = 7.9898(4) Å, c = 7.4868(4) Å, β = 104.398(3)°, V = 278.93(2) ų, Z = 2, D_x = 3.104 g · cm^-3. The structure is characterized by FeO₆ octahedra sharing common O-corners with six neighbouring PO₄ tetrahedra to form a three-dimensional framework. Lithium cations are located within channels running along [100]. The channels are formed by eight-membered rings resulting from the connection of alternating FeO₆ octahedra (4×) and phosphate tetrahedra (4×). High-resolution diffraction data allowed to refine a split model for the position of the hydrogen atom. Magnetization data confirm the valence state 3+ for iron and detect an antiferromagnetic ordering of the iron moments below 23.6 K. Thermal decomposition of the compound was investigated by DTA/TG methods.     

Preparation and Crystal Structure of Potassium Iron Hydrogen Phosphate,KFe3(HPO4)2(H2PO4)6 · 4 H2O

Single crystals of potassium iron hydrogen phosphate, KFe₃(HPO₄)₂(H₂PO₄)₆ · 4 H₂O, were prepared hydrothermally by heating a mixture of Fe₂O₃, H₃PO₄ and K₂CO₃ with a small amount of water. It crystallizes monoclinic, space group C2/c (N° 15 Int. Tab.) with Z = 4 and a = 1701(2), b = 960.4(5), c = 1750(1) pm, β = 90.88(7)°. The crystal structure was solved by using 1716 unique reflections F₀ > 4σ(F₀) with a final wR2 value of 0.126 (SHELXL-93). The main feature of the crystal structure are layers formed by PO₄-tetrahedra around the FeO₆-octahedra parallel to (001). K⁺ and H₂O molecules connect these layers. Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), Charge Distribution (CHARDI) and the Madelung Part of Lattice Energy (MAPLE) are calculated for the title compound. The existence of hydrogen bonds is confirmed by these calculations.     

Beiträge zum thermischen Verhalten und zur Kristallchemie von wasserfreien Phosphaten XXXII [1] Neue Orthophosphate des zweiwertigen Chroms — Mg3Cr3(PO4)4, Mg3, 75Cr2, 25(PO4)4, Ca3Cr3(PO4)4 und Ca2, 00Cr4, 00(PO4)4

Contributions on Crystal Chemistry and Thermal Behaviour of Anhydrous Phosphates. XXXII. New Orthophosphates of Divalent Chromium — Mg₃Cr₃(PO₄)₄, Mg_{3, 75}Cr_{2, 25}(PO₄)₄, Ca₃Cr₃(PO₄)₄ and Ca_{2, 00}Cr_{4, 00}(PO₄)₄ Solid state reactions via the gas phase led in the systems A₃(PO₄)₂ / Cr₃(PO₄)₂ (A = Mg, Ca) to the four new compounds Mg₃Cr₃(PO₄)₄ ( A ), Mg_3.75Cr_2.25(PO₄)₄ ( B ), Ca₃Cr₃(PO₄)₄ ( C ), and Ca_2.00Cr_4.00(PO₄)₄ ( D ). These were characterized by single crystal structure investigations [( A ): P2₁/n, Z = 1, a = 4.863(2) Å, b = 9.507(4) Å, c = 6.439(2) Å, β = 91.13(6)°, 1855 independend reflections, 63 parameters, R1 = 0.035, wR2 = 0.083; ( B ): P2₁/a, Z = 2, a = 6.427(2) Å, b = 9.363(2) Å, c = 10.051(3) Å, β = 106.16(3)°, 1687 indep. refl., 121 param., R1 = 0.032, wR2 = 0.085; ( C ): P‐1, Z = 2, a = 8.961(1) Å, b = 8.994(1) Å, c = 9.881(1) Å, α = 104.96(2)°, β = 106.03(2)°, γ = 110.19(2)°, 2908 indep. refl., 235 param., R1 = 0.036, wR2 = 0.111; ( D ): C2/c, Z = 4, a = 17.511(2) Å, b = 4.9933(6) Å, c = 16.825(2) Å, β = 117.95(1)°, 1506 indep. refl., 121 param., R1 = 0.034, wR2 = 0.098]. The crystal structures contain divalent chromium on various crystallographic sites, each showing a (4+n)‐coordination (n = 1, 2, 3). For the magnesium compounds and Ca_2.00Cr_4.00(PO₄)₄ a disorder of the divalent cations Mg²⁺/Cr²⁺ or Ca²⁺/Cr²⁺ is observed. Mg_3.75Cr_2.25(PO₄)₄ adopts a new structure type, while Mg₃Cr₃(PO₄)₄ is isotypic to Mg₃(PO₄)₂. Ca₃Cr₃(PO₄)₄ and Ca_2.00Cr_4.00(PO₄) ₄ are structurally very closely related and belong to the Ca₃Cu₃(PO₄)₄‐structure family. The orthophosphate Ca₉Cr(PO₄)₇, containing trivalent chromium, has been obtained besides C and D .     

Fe6.67(PO4)5.35(HPO4)0.65 and Fe6.23(PO4)4.45(HPO4)1.55: two new mixed‐valence iron phosphates

Two new mixed‐valence iron phosphates, namely heptairon pentaphosphate hydrogen phosphate, Fe_6.67(PO₄)_5.35(HPO₄)_0.65, and heptairon tetraphosphate bis(hydrogen phosphate), Fe_6.23(PO₄)_4.45(HPO₄)_1.55, have been synthesized hydrothermally at 973 K and 0.1 GPa. The structures are similar to that of Fe^II₃Fe^III₄(PO₄)₆ and are characterized by infinite chains of Fe polyhedra parallel to the [101] direction. These chains are formed by the Fe1O₆ and Fe2O₆ octahedra, alternating with the Fe4O₅ distorted pentagonal bipyramids, according to the stacking sequence ...Fe1–Fe1–Fe4–Fe2–Fe2.... The Fe3O₆ octahedra and PO₄ tetrahedra connect the chains together. Fe^II is localized on the Fe3 and Fe4 sites, whereas Fe^III is found in the Fe1 and Fe2 sites, according to bond‐valence calculations. Refined site occupancies indicate the presence of vacancies on the Fe4 site, explained by the substitution mechanism Fe^II + 2(PO₄³⁻) = vacancies + 2(HPO₄²⁻).     

New complex ytterbium molybdophosphates M 2 I Yb(PO4)(MoO4) (MI = K, Na): Synthesis and structure solution

Complex rare-earth molybdophosphates of sodium and potassium (Na₂Yb(PO₄)(MoO₄) (I) and K₂Yb(PO₄)(MoO₄) (II) are synthesized by solid-phase reactions at 600°C (for I) and 750°C (for II). The molybdophosphates are characterized using powder X-ray diffraction, laser second harmonic generation (SHG), IR spectroscopy, and differential thermal analysis. Their structures are refined using the Rietveld technique. The compounds are isostructural and crystallize in an orthorhombic system (space group Ibca, Z = 8). The unit cell parameters are a = 18.0086(1) Å, b = 12.0266(1) Å, c = 6.7742(1) Å for compound I and a = 19.6646(1) Å, b = 12.0570(1) Å, c = 6.8029(1) Å for compound II. The structures are built of YbO₈ chains extended along axis c and linked into layers through PO₄ tetrahedra. The Na⁺ cations (CN = 6) and the K⁺ cations (CN = 8) reside in the interlayer spaces.     

Two Modifications of NH4HPO3F: Synthesis and Crystal Structure

The α and β modifications of NH₄HPO₃F were synthesized and characterized with single crystal X‐ray diffraction. The crystal structure of α‐NH₄HPO₃F determined at 180 K is monoclinic, space group P2₁/n, with a = 7.4650(1), b = 15.586(2), c = 7.5785(9) Å, β = 108.769(9)°, V = 834.9(2) ų, Z = 8, and R₁ = 0.0376 and wR₂ = 0.0818. β‐NH₄HPO₃F measured at 310 K crystallizes in the triclinic space group, P 1, with a = 7.481(1), b = 7.511(1), c = 7.782(1) Å, α = 84.31(1), β = 84.20(1), γ = 68.67(2)°, V = 404.31(9) ų, Z = 4, and R₁ = 0.0254 and wR₂ = 0.0735. A phase transition was not observed between 180 and 310 K for β‐NH₄HPO₃F. Both modifications of NH₄HPO₄F consist of HPO₃F^– and NH₄⁺ units. Two pairs of two unique anions are linked to each other by O–H…O hydrogen bonds to form cyclic tetramers held together by N–H…O bonds. No O–H…F or N–H…F bonds were observed.     

Hydrothermal synthesis and crystal structure of a new ammonium gallium hydroxyphosphate (NH4)Ga(OH)PO4

A new ammonium gallium hydroxyphosphate (NH₄)Ga(OH)PO₄ was synthesized under mild hydrothermal conditions (200°C, τ = 168 h). The equimolar content of Ga and P was determined by chemical analysis and electron probe X-ray microanalysis. The presence of NH₄ and OH groups was demonstrated by IR and Raman spectroscopy. An ab initio model of the crystal structure was refined by the Rietveld method (space group P2₁/m, Z = 2): a = 4.4832(1) Å, b = 6.0430(1) Å, c = 8.5674(1) Å, β = 98.019(1)°, R _p = 0.0552, R _wp = 0.0723. A zero SHG signal (T = 300 K) confirmed a centrosymmetric structure of the compound. The structure contains layers composed of GaO₄(OH)₂ octahedra and PO₄ tetrahedra. The interlayer space accommodates ammonium cations. The layer is based on linear chains of edge-sharing GaO₄(OH)₂ octahedra with a zigzag trans-arranged-Ga-(OH)-Ga-(OH)-backbone. The construction of the layer in (NH₄)Ga(OH)PO₄ was found to be topologically related to that in (En)_0.5Fe(OH)PO₄. The effect of the gradual F^? → OH^? substitution in the quasi-morphotropic series (NH₄)GaF_1-δ(OH)_δPO₄ (δ = 0, 0.5, 1.0) on the degree of polarization of the mixed anionic radical was considered. (NH₄)Ga(OH)PO₄ is thermally unstable: removal of NH₃ and H₂O molecules in the range 170–450°C is accompanied by the formation of two polymorphs of GaPO₄.     

Synthesis and Structure of a Molecular Zinc Phosphate [(C12H8N2Zn)2(HPO4)(H2PO4)2]

A hydrothermal reaction of a mixture of ZnCO₃, phosphoric acid, 1, 10‐phenanthroline in H₂O gave rise to large plates of a new zinc phosphate, [(C₁₂H₈N₂Zn)₂(HPO₄)(H₂PO₄)₂], I . The structure consists of ZnO₃N₂ distorted trigonal‐bipyramidal and PO₄ tetrahedral units linked through their vertices to give rise to a zero‐dimensional molecular solid (monomer). The structure of the monomer appears to be similar to the secondary building unit (SBU) 4 = 1, commonly found in many fibrous zeolites. To our knowledge, this is the first time this building unit has been isolated. The structure, with a unique composition, is stabilized by hydrogen bond interactions between the terminal —OH groups forms a one‐dimensional molecular wire and also by strong π…π interactions between the 1, 10‐phenanthroline units. Photoluminescence studies show that there is a ligand‐to‐metal charge transfer (LMCT). Crystal data: orthorhombic, space group = Fdd2 (no. 43), a = 40.4669(1), b = 7.4733(2), c = 17.4425(5)Å, V = 5274.9(2)ų, Z = 8.     

Hydrothermal Synthesis and Crystal Structure of CaIn2(PO4)2(HPO4): An octahedral-tetrahedral framework ternary calcium indium(III) phosphate

The new ternary calcium indium(III) phosphate CaIn₂(PO₄)₂(HPO₄) with mixed octahedral-tetrahedral framework was synthesized through hydrothermal reaction of stoichiometric amounts of CaO and InCl₃ with excess of H₃PO₄ and H₂O at pH = 1. Single crystal x-ray diffraction studies show the compound to crystallize in monoclinic symmetry, space group P2₁/n (#14) with a = 657.08(6), b = 2023.7(2), c = 665.72(7) pm, β = 91.20(1)°, Z = 4 and R = 0.043. The framework is built up of dimers of edge-sharing InO₆ octahedra forming In₂O₁₀ units sharing all their OXO ligands with PO₄ tetrahedra, and HPO₄ groups.     

Structure,infrared and Raman spectroscopic studies of newly synthetic AII(SbV0.50FeIII0.50)(PO4)2 (ABa,Sr, Pb) phosphates with yavapaiite structure

The synthesis and structural study of three new A^II(Sb^V_0.5Fe^III_0.5)(PO₄)₂ (ABa, Sr, Pb) phosphates belonging to the ASbFePO system were reported here for the first time. Structures of [Ba], [Sr] and [Pb] compounds, obtained by solid state reaction in air atmosphere, were determined at room temperature from X-ray powder diffraction using the Rietveld method. Ba^II(Sb^V_0.5Fe^III_0.5)(PO₄)₂ features the yavapaiite-type structure, with space group C2/m, Z = 2 and a = 8.1568(4) Å; b = 5.1996(3) Å c = 7.8290(4) Å; β = 94.53(1)°. A^II(Sb^V_0.5Fe^III_0.5)(PO₄)₂ (ASr, Pb) compounds have a distorted yavapaiite structure with space group C2/c, Z = 4 and a = 16.5215(2) Å; b = 5.1891(1) Å c = 8.0489(1) Å; β = 115.70(1)° for [Sr]; a = 16.6925(2) Å; b = 5.1832(1) Å c = 8.1215(1) Å; β = 115.03(1)° for [Pb]. Raman and Infrared spectroscopic study was used to obtain further structural information about the nature of bonding in selected compositions.     

Hydrothermal synthesis and structural determination of a three-dimensional microporous iron(III)phosphate: [H3N(CH2)4NH3]3[Fe8(HPO4)12(PO4)2(H2O)6]

A new microporous iron (III) phosphate, [H₃N(CH₂)₄NH₃]₃[Fe₈(HPO₄)₁₂(PO₄)₂(H₂O)₆], has been prepared using low temperature hydrothermal methods and characterized by single-crystal X-ray diffraction, EDAX, infrared spectroscopy, thermogravimetric analysis and bond valence sums. The title compound crystallizes as light pink hexagonal-shaped tabs in the centrosymmetric hexagonal space group 3¯ (No.147) with a = b = 13.495(2) Å, c = 9.396(2) Å, V = 1481.9(4) ų and Z = 4 with R/R_w = 0.044/0.048. The compound exhibits a complicated three-dimensional microporous structure with quaternary ammonium ions acting as a template for the framework. It is similar to previously reported [HN(CH₂CH₂)₃NH]₃[Fe₈(HPO₄)₁₂(PO₄)₂(H₂O)₆].