High-Temperature Synthesis of the Mg2-x Ca xP4O12 and Cd2-x CaxP4O12

Abstract

The cyclo-tetraphosphates of the M^II _2-xCa_xP₄O₁₂ type (MI^II = Mg, Cd) have been synthetized as new binary compounds, and their existence for x ε (0; 1 > (Mg) or for x ε (0; 0.7 > (Cd) has been proved. The synthesis is based on a two-step thermal process. The first step starts from pure cyclo-tetraphosphates of the two divalent metals and Ca(PO₃)₂ which are melted in normal atmosphere and then abruptly cooled to give a vitreous amorphous product composed of higher linear phosphates of the summary formula (M^II _2-x Ca_x)_n/4H₂P_nO_3n+1 · In the second step, this product is repeatedly heated to a suitable temperature and recrystallized to give microcrystalline product M^II _2-x Ca_xP₄O₁₂ · The colourless (white) products crystallize in the monoclinic aystem, C2c group. Their structural parameters have the values for Mg_2-x Ca_xP₄O₁₂: a = 11.749(5) to 12.063(4) Å, b = 8.278(4) to 8.635(4) Å c = 9.905(4) to 9.875(3) Å and β = 118.92(2)° to 118.03(2)°; or for Cd_2-x Ca_xP₄O₁₂: a = 12.328(4) to 12.457(5) Å b = 8.639(3) to 8.732(4) Å c = 10.388(3) to 10.443(4) Å and β = 119.33(2)° to 119.45(2)°.     

(Mg1–xCrx)2P2O7, CaCrP2O7, SrCrP2O7 und BaCrP2O7 – Neue Diphosphate des zweiwertigen Chroms

Contributions on Crystal Chemistry and Thermal Behaviour of Anhydrous Phosphates. XXXI. (Mg_1–xCr_x)₂P₂O₇, CaCrP₂O₇, SrCrP₂O₇ and BaCrP₂O₇ – New Diphosphates of Divalent Chromium In the quasi‐binary systems A₂P₂O₇/Cr₂P₂O₇ (A = Mg, Ca, Sr, Ba) the solid solution (Mg_1–xCr_x)₂P₂O₇ as well as the new compounds CaCrP₂O₇, SrCrP₂O₇, and BaCrP₂O₇ have been synthesized and characterized for the first time. In the whole experimental range (0.01 < x < 0.94; T = 950 °C) the solid solution (Mg_1–xCr_x)₂P₂O₇ is isotypic to the pure phases β‐Mg₂P₂O₇ and β‐Cr₂P₂O₇; but no phase transition (β → α) to a low‐temperature modification, as in Mg₂P₂O₇ and Cr₂P₂O₇, was found. CaCrP₂O₇ ( A ), SrCrP₂O₇ ( B ), and BaCrP₂O₇ ( C ), phases without detectable homogenity range in the other quasi‐binary systems are not structurally related to each other, but are isotypic to the corresponding compounds containing cobalt. [( A ): P‐1, Z = 2, a = 6.312(2) Å, b = 6.499(2) Å, c = 6.916(2) Å, α = 83.12(3)°, β = 88.37(3)°, γ = 67.72(3)°, 3235 independent reflections, R1 = 0.041, wR2 = 0.112; ( C ): P‐1, Z = 2, a = 5.382(8) Å, b = 7.271(8) Å, c = 7.589(4) Å, α = 103.33(7)°, β = 89.91(9)°, γ = 93.6(1)°, 1571 independent reflections, R1 = 0.085, wR2 = 0.31]. We have reported earlier details on SrCrP₂O₇. The coordination of Cr²⁺ by oxygen is distorted octahedral in ( A) , while in the structures of ( B) and ( C) square‐pyramidal environment is found. The results of UV/VIS‐spectroscopic and magnetic measurements as well as IR‐spectra of the diphosphates are reported.     

Die Kristallstruktur des Bleicyclotetraphosphat-2-Hydrats,Pb2P4O12 · 2H2O

Crystal Structure of Lead Cyclotetraphosphate-2-Hydrate, Pb₂P₄O₁₂ · 2H₂O By heating of Pb₂P₄O₁₂ · 4 H₂O crystals at 100°C, Pb₂P₄O₁₂ · 2 H₂O is formed topotactically. The triclinic crystals are twinned on (010). Space group: P1 , unit cell: a = 8.02 ± 0.02, b = 10.58 ± 0.02, c = 7.53 ± 0.02 Å, α = 98.8 ± 0.2, β = 108.7 ± 0.2, γ = 82.6 ± 0.3°. The crystal structure was determined by Patterson and Fourier methods and refined by least-squares calculations. The structure consists of two crystallographically different P₄O₁₂^4? ring anions, point symmetry 1 , connected by Pb and hydrogen bonds. Both Pb atoms are coordinated by eight oxygen atoms. The polyhedra of either Pb are interconnected by common edges forming sheets and chains. Pb(1) is joined with four, Pb(2) with five P₄O₁₂^4? anions.     

Beiträge zum Koordinationsverhalten von Oxidionen in anorganischen Feststoffen. III [1] Mn2P2O7, Mn2P4O12 und Mn2Si(P2O7)2 — Kristallzüchtung,Strukturverfeinerungen und Elektronenspektren von Mangan(II)‐Phosphaten

Contributions on the Bonding Behaviour of Oxygen in Inorganic Solids. III [1] Mn₂P₂O₇, Mn₂P₄O₁₂ und Mn₂Si(P₂O₇)₂ — Crystal Growth, Structure Refinements and Electronic Spectra of Manganese(II) Phosphates By chemical vapour transport reactions in a temperature gradient single crystals of Mn₂P₂O₇ (1050 → 950 °C) and Mn₂P₄O₁₂ (850 → 750 °C) have been obtained using P/I mixtures as transport agent. Mn₂Si(P₂O₇)₂ was crystallized by isothermal heating (850 °C, 8d; NH₄Cl as mineralizer) of Mn₂P₄O₁₂ und SiO₂. In Mn₂Si(P₂O₇)₂ [C 2/c, a = 17.072(1)Å, b = 5.0450(4)Å, c = 12.3880(9)Å, β = 103.55(9)°, 1052 independent reflections, 97 variables, R1 = 0.023, wR2 = 0.061] the Mn²⁺ ions show compressed octahedral coordination (d¯_Mn—O = 2.19Å). The mean distance d¯_Mn—O = 2.18Å was found for the radially distorted octahedra [MnO₆] in Mn₂P₄O₁₂ [C 2/c, Z = 4, a = 12.065(1)Å, b = 8.468(1)Å, c = 10.170(1)Å, β = 119.29(1)°, 2811 independent reflections, 85 variables, R1 = 0.025, wR2 = 0.072]. Powder reflectance spectra of the three pink coloured manganese(II) phosphates have been measured. The spectra show clearly the influence of the low‐symmetry ligand fields around Mn²⁺. Observed d—d electronic transition energies and the results of calculations within the framework of the angular overlap model (AOM) are in good agreement. Bonding parameters for the manganese‐oxygen interaction in [Mn²⁺O₆] chromophors as obtained from the AOM treatment (B, C, Trees correction α, e_σ, e_π) are discussed.     

Neue Oxocuprate (I). Über Cs3Cu5O4, Rb2KCu5O4, RbK2Cu5O4 und K3Cu5O4

New Oxocuprates(I). On Cs₃Cu₅O₄, Rb₂KCu₅O₄, RbK₂Cu₅O₄ and K₃Cu₅O₄ Cs₃Cu₅O₄ light yellow, powder as well as single crystals [a = 10.313(9), b = 7.630(1), c = 14.750(4) Å, β = 106.48(6)°], Rb₂KCu₅O₄ [a = 9.724(2), b = 7.443(0), c = 14.246(2) Å, β = 106.78(8)°], RbK₂Cu₅O₄ [a = 9.561(1), b = 7.411(0), c = 14.111(1) Å, β = 106.76(7)°] and K₃Cu₅O₄ [a = 9.422(1), b = 7.364(1), c = 13.995(2) Å, β = 107.00(2)°] are new prepared. The colour of the powders becomes lighter according to the sequence showed above. K₃Cu₅O₄ shows pale yellow. The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Beiträge zum thermischen Verhalten und zur Kristallchemie von wasserfreien Phosphaten. XV. Darstellung,Kristallstruktur und Eigenschaften von Kupfer(II)-ultraphosphat CuP4O11 (≙ Cu2P8O22)

Synthesis, Crystal Structure, and Properties of Copper(II) Ultraphosphate CuP₄O₁₁ CuP₄O₁₁ was synthesised from Cu₂P₄O₁₂ and P₄O₁₀ (500°C, sealed silica ampoules) using iodine and a few mg of CuP₂ or phosphorus as mineraliser. Chemical transport reactions in a temperature gradient 600 → 500°C led to the formation of well developed, colourless, transparent crystals with edge-lengths up to 5 mm (deposition rate m ≈? 2 mg/h). The crystal structure of copper(II) ultraphosphate (C1 ; Z = 8; a = 13.084(3) Å, b = 13.024(2) Å, c = 10.533(2) Å, α = 89.28(2)°, β = 118.42(2)°, γ = 90.30(2)°) has been determined and refined from X-ray data obtained from a pseudo-merohedrally twinned crystal (twin element two-fold rotation axis // b; volume ratio: 17/3; 3063 independent reflections with 2θ ? 53.4°; 291 variables; conventional residual (based on F) R1 = 0.038, wR2 = 0.101 (based on F²), GooF = 1.10). The crystal structure of CuP₄O₁₁ is built from four crystallographically independent ten-membered polyphosphate rings of very similar conformation. These rings are linked to form two-dimensional nets parallel (?2 0 1) planes. There is a close topological relationship between these nets and those formed in polyphosphides CdP₄ and CuP₂. Copper on two crystallographic sites (Cu₂P₈O₂₂) is coordinated by oxygen thus forming elongated [CuO₆] octahedra (d_eq(Cu? O) ≈? 1.96 Å; d_ax(Cu? O) ≈? 2.34 Å). The crystal g-tensor of CuP₄O₁₁ has been determined from powder samples to g₁ = 2.09, g₂ = 2.24, g₃ = 2.36. These values are in good agreement with molecular g-values from calculations within the framework of the angular overlap model on the two independent CuO₆ octahedra (Cu²⁺(1): g_x = 2.09, g_y = 2.10, g_z = 2.52; Cu²⁺(2): g_x = 2.08, g_y = 2.11, g_z = 2.52) assuming exchange coupling. The observed broad absorption band (7000 cm^?1 to 13000 cm^?1) from powder reflectance measurements (4000–28000 cm^?1) and the bulk magnetic susceptibility of μ_exp = 1.99 μ_B is also reproduced nicely by this calculations.     

Crystal structure of the cyclotetraphosphate Ca2[P4O12] · 4 H2O

Ca₂[P₄O₁₂] · 4 H₂O crystallizes in the monoclinic space group P2₁/n, a = 7.668, b = 12.895, c = 7.144 Å, β 107.00°, D_x = 2.28 g · cm^?3, Z = 2. In the structure there are ringlike anions, which are composed of 4 PO₄ tetrahedra connected by oxygen bridges. The Ca²⁺ are surrounded by 7 oxygen atoms. Each two cation polyhedra are connected by a common edge to pairs which are isolated from one another. The water molecules form hydrogen bridges with one another and with the anion rings.     

Die Kristallstruktur des Bleicyclotetraphosphat-4-Hydrats,Pb2P4O12 · 4H2O

Crystal Structure of Lead Cyclotetraphosphate-4-Hydrate, Pb₂P₄O₁₂·4 H₂O Pb₂P₄O₁₂·4 H₂O is the starting product of a series of solid state reactions with the final product cyclooctaphosphate. Pb₂P₄O₁₂·4 H₂O crystallizes in the monoclinic space group P2₁/n, with a = 8.07 ± 0.02, b = 11.76 ± 0.03, c = 7.50 ± 0.02 Å and β = 108.2 ± 0.3°. The crystal structure has been solved by Patterson and Fourier methods and refined by least squares calculations to an R-index of 0.07. The structure consists of P₄0₁₂^4? ringanions, which are connected by Pb and hydrogen bonds. Lead is coordinated by eight oxygen atoms.     

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.     

Synthese und Kristallstruktur von Pb2P4O12 · 3 H2O

Synthesis and Crystal Structure Determination of Pb₂P₄O₁₂ · 3 H₂O Pb₂P₄O₁₂ · 3 H₂O precipitates at mixing aqueous solutions of Pb(NO₃)₂ and Na₄P₄O₁₂ (25°C). Crystal growth was achieved by applying gel-techniques (Agar-Agar-gel). The crystal structure (P1 , a = 786.4(3), b = 914.4(3), c = 1021.6(3) pm, α = 97.42(2)°, β = 100.63(2)°, γ = 114.92(2)°; Z = 2; 4160 unique diffractometer data, R = 0.05) contains cyclo-tetraphosphate anions with point symmetry D_2d. Lead is coordinated by eight oxygen, the polyhedra deriving from a square antiprism.     

The Ring Acid,H6P6O12 and Ring Acid,H4P4O10 and Their Salts

Abstract

The hydrated salts of the acid H₆P₆O₁₂, Rb₆P₆O·aq and M₃P₆O₁₂·aq (M = Ca, Sr, Ba), that have so far been unknown, have been prepared and studied by X-ray methods, thermal analysis and molecular spectroscopy. It has been found that the anion structure exhibits a chair form with the D_3d symmetry. All the salts are stable at laboratory temperature and are completely decomposed on prolonged heating to 80°C prior to complete dehydration. The newly prepared salts of the acid H₄P₄O₁₀ involve Cs₄P₄0₁₀·1.5 H₂O, Tl₄P₄O₁₀, M₂P₄O₁₀·x H₂O (M = Cu, Ni, Co; x = 10, 2, 6, respectively), Na₂MP₄O₁₀·x H₂O (M = Cu, Ni, Co; x = 8, 8, 4, respectively). They have been studied using X-ray methods, thermal analysis, molecular and reflectance spectra and the magnetic susceptibility. The dehydration of the salts starts at 30 to 40°C and ends by complete decomposition before the completion of dehydration at 150°C. The anion structure for the salt CS₄P₄O₁₀ in the crystalline state has a chair form with C₂ symmetry. However, the anion structure in aqueous solutions approaches a planar arrangement with the D_2h symmetry.     

Verbesserte Darstellung,Kristallzüchtung und Strukturanalyse von P4O6S2 und P4O6S3

Improved Syntheses, Crystal Growth, and Crystal Structure Determination of P₄O₆S₂ and P₄O₆S₃ Syntheses and single crystal growths of the title compounds are described. Both compounds crystallize in the space group P2₁/c (P₄O₆S₂: a = 11.293(4); b = 6.457(3); c = 11.588(4) Å; β = 90.29(2)°, 2 450 diffractometer data, R_w = 0.035/P₄O₆S₃: a = 15.611(5); b = 8,303(3); c = 9.697(4) Å; β = 127.12(2)°, 2 481 diffractometer data, R_w = 0.034). The structural data for the series P₄O₆S_n (n = 1 – 4) thus completed are compared to their oxide analogues P₄O₆O_n (n = 1 – 4). The changes in the geometry of the P₄O₆-cage in course of its successive oxidation are discussed.     

Synthesis,Crystal Structure and Characterization of the Copper Iron Phosphate Cu8Fe2O5(PO4)4

The system CuO‐Fe₂O₃‐P₂O₅ has been investigated by means of the solid state reaction between CuO, Fe₂O₃ and (NH₄)₂HPO₄ in quartz crucibles at 900 °C. The powder samples were characterized by X‐ray diffraction, IR spectroscopy and TG/DTA. Single crystals of a new quaternary phase Cu₈Fe₂P₄O₂₁ were achieved by cooling from the melt of the compound in a sealed, evacuated quartz ampoule. Cu₈Fe₂O₅(PO₄)₄ crystallizes in the monoclinic space group C2/m (No 12) with a = 15.9733(8) Å, b = 5.9438(3) Å, c = 9.5530(5) Å, β = 113.76(1)°, Z = 2. The three‐dimensional framework consists of [FeO₆] octahedra, three different [CuO₅] polyhedra and [PO₄] tetrahedra. Cu₈Fe₂P₄O₂₁ exhibits an incongruently melting point at 945 °C.     

Chemische,thermoanalytische und röntgenorgraphische Untersuchungen zur Bildung des β-Ca2[P2O7] aus dem Ca2[P4O12] · 4 H2O

Chemical, Thermoanalytical, and X-ray Investigations to the Formation of the β-Ca₂[P₂O₇] from the Ca₂[P₄O₁₂] · 4 H₂O The formation of β-Ca₂[P₂O₇] from Ca₂[P₄O₁₂] · 4 H₂O (modification I) proceeds crystallographically oriented in several steps: In one of these steps an X-ray amorphous phase is formed and simultaneously cyclotetraphosphate reorganizes to polyphosphate. The dehydration proceeds in 2 steps: At 120°C 3 molecules and at 220°C 1 molecule are lost, respectively. The formation of diphosphate from polyphosphate, which is connected with the loss of P₂O₅, takes place at 850°C according to high temperature Guinier.     

Crystal structures of CrH2P3O10 and InH2P3O10

The crystal structures of chromium and indium dihydrogen triphosphates, CrH₂P₃O₁₀ and InH₂P₃O₁₀, in modification II are refined by the Rietveld method using X-ray powder diffraction data. The compounds crystallize in the monoclinic crystal system, space group P21/n. Z = 4, a = 7.3225(4)Å, b = 8.6835(6)Å, c = 11.6599(7) Å, and b = 102.388(3)° for CrH₂P₃O₁₀, and a = 7.5332(1)Å, b = 9.0841(1)Å, c = 11.8600(1) Å, and b = 103.9596(7)° for InH₂P₃O₁₀. The structures are refined in the isotropic approximation (pseudo-Voigt profile function): R_p = 4.8%, R_wp = 6.9%, R_Bragg = 7.5%, R_F = 9.9% for CrH₂P₃O₁₀; R_p = 6.3%, R_wp = 8.3%, R_Bragg = 6.2%, R_F = 4.1% for InH₂P₃O₁₀. The crystal structures of compounds in the isostructural series M^IIIH₂P₃O₁₀-II, where M^III = Al, Ga, Cr, V, Fe, and In, are examined and compared.     

Etude des spectres vibrationnels et des proprietes physico-chimiques du cyclotriphosphate mixte de nickel et de sodium hexahydrate,NiNa4(P3O9)2.6H2O

A study of the vibrational spectra and physico-chemical properties of nickel and sodium cyclotriphosphate hexahydrate, NiNa₄(P₃O₉)₂.6H₂O. We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate hexahydrate of nickel and sodium, NiNa₄(P₃O₉)₂.6H₂O, between 25 and 700°C by infrared spectrometry, X-ray diffraction, TGA and DTA thermal analyses. This study allows the identification and the crystallographic characterization of a new phase, NiNa₄(PO₃)₆, obtained between 350 and 450°C. NiNa₄(PO₃)₆ crystallizes in the triclinic system, P₋₁, with the following unit cell parameters a = 6.157(3)Å, b = 6.820(6)Å, c = 10.918(6)Å, α = 80.21(5)°, β= 97.80(9)°, γ = 113.49(3)°, V = 409.8 ų, Z = 1, M(19) = 25 and F(19) = 48 (0.0095; 42). The calcination of NiNa₄(PO₃)₆, between 500 and 600°C, leads to a mixture of long-chain polyphosphates NiNa(PO₃)₃ and NaPO₃. The kinetic characteristics of the dehydration of NiNa₄(P₃O₉)₂.6H₂O were determined and discussed. The vibrational spectrum of the title compound, NiNa₄(P₃O₉)₂.6H₂O, was interpreted in the domain of the stretching vibrations of the P₃O₉ rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P₃O₉ ring with D_3h symmetry.     

(Ni3–xMgx)[B3P3O12(OH)6] · 6 H2O (x ≈ 1.5): A Novel BorophosphateHydrate Containing Isolated Six‐Membered Rings of Tetrahedra

A novel borophosphate‐hydrate, (Ni_3–xMg_x)[B₃P₃O₁₂(OH)₆] · 6 H₂O (x ≈ 1.5), has been prepared by hydrothermal synthesis (T = 170 °C) from a mixture of NiCl₂ · 6 H₂O, Mg(OH)₂, B₂O₃ and H₃PO₄. The crystal structure was determined at 293 K from single‐crystal X‐ray diffraction data (trigonal, R3c (no. 167), a = 14.957(10) Å, c = 13.812(6) Å, V = 2676(2) ų, Z = 6, R₁ = 0.0276, wR₂ = 0.0714 for 779 observed reflections with I > 2σ(I)). The crystal structure contains unbranched six‐membered rings [B₃P₃O₁₂(OH)₆]^6– of alternating corner linked borate and phosphate tetrahedra, which are stacked along [001] and connected via M^IIO₂(OH)₂(H₂O)₂ coordination polyhedra. Hydrogen bonding between the tetrahedral six‐membered rings and M^IIO₂(OH)₂(H₂O)₂ octahedra leads to a further cross‐linking. With respect to the arrangement of isolated six‐membered tetrahedral rings the crystal structure of this borophosphate‐hydrate is closely related to the cyclo‐hexasilicate dioptase, Cu₆[Si₆O₁₈] · 6 H₂O.     

Crystal structure of zinc-tetrametaphosphate octahydrate: Zn2P4O12 · 8 H2O

Crystal structure of zinc tetrametaphosphate octahydrate: Zn₂P₄O₁₂ · 8 H₂O has been solved using 1888 X-ray reflections with a final R value: 0.031. This salt is triclinic, P1 , with Z = 1 and the following unit cell dimensions: a = 8.610(5), b = 7.137(5), c = 7.108(5) Å, α = 96.09(5), β = 105.99(5), γ = 100.49(5)°. This salt is the third example of an hydrated tetrametaphosphate of a bivalent cation. The two zinc atoms are octahedrally coordinated. A complete hydrogen bond scheme is given.     

The Synthesis and Characterization of a New Cobalt Dimethylphenylpiperazinium Cyclotetraphosphate Hexahydrate,Co[C12 H19 N2]2 P4 O12.6 H2 O

Cobalt dimethylphenylpiperazinium cyclotetraphosphate hexahydrate, Co[C₁₂H₁₉N₂]₂P₄O₁₂.6H₂O, was synthesized by a reaction between cyclotetraphosphoric acid H₄P₄O₁₂, cobalt carbonate, and 1-(2,4-dimethylphenylpiperazine). It crystallizes in the triclinic system, space group P, with the following unit cell parameters: a = 7.336(1), b = 8.413(1), c = 14.926(2) Å, α = 87.46(1), β = 83.13(1), γ = 82.98(1)°, V = 907.3(2) ų, and Z = 1. The atomic arrangement can be described as layers containing P₄O₁₂ rings a and Co(H₂O)₆ octahedra spreading in the (001) planes between which are located the dimethylphenylpiperazinium groups via H-bonds. The synthesis and characterization by X-ray diffraction, IR absorption, and thermal analysis are described.