The system YPO4Ca3(PO4)2Ca2P2O7

The ternary system YPO₄Ca₃(PO₄)₂Ca₂P₂O₇ has been investigated by differential thermal analysis, powder X-ray diffraction, and microscopy in reflected light. Its phase diagram and isothermal section at room temperature have been determined. The system contains only one double phosphate which is formed at the 1:1 molar ratio YPO₄:Ca₃(PO₄)₂, i.e., Ca₃Y(PO₄)₃.     

Sodium ion-conducting solid electrolytes in the system Na3PO4Na2SO4

In the system Na₃PO₄Na₂SO₄, the high-temperature, cubic γ form of Na₃PO₄ forms an extensive range of solid solutions: Na_3−x(P_1−xS_x)O₄, 0 < x < (0.57 to 0.70, depending on temperature). For compositions in the range x = ca. 0.33 to 0.57, these γ solid solutions are thermodynamically stable at all temperatures. The conductivity of the γ solid solutions increases with increasing x and reaches a maximum at x = 0.5 to 0.6, with values of 2 × 10⁻⁵ ohm⁻¹ cm⁻¹ at 100°C, rising to 1.3 × 10⁻² ohm⁻¹ cm⁻¹ by 300°C; this conductivity increase with x is attributed to an increase in the sodium ion vacancy concentration, associated with the solid solution mechanism Na + PS. The phase diagram for the system Na₃PO₄Na₂SO₄ is given together with lattice parameters of the γ solid solutions.     

Investigation of phase equilibria in the Er2O3–Na2O–P2O5 system: the partial system ErPO4–NaPO3–Er(PO3)3

The partial system ErPO₄–NaPO₃–Er(PO₃)₃ of the Er₂O₃–Na₂O–P₂O₅ oxide system has been investigated by thermoanalytical methods and X-ray powder diffraction. On the basis of the obtained results the phase diagram of the partial system is proposed. The system is bounded by three subsystems: (i) ErPO₄–Er(PO₃)₃, (ii) Er(PO₃)₃–NaPO₃ and (iii) ErPO₄–NaPO₃. Their phase diagrams are proposed. In the Er(PO₃)₃–NaPO₃ subsystem an intermediate compound NaEr(PO₃)₄ occurs; it melts incongruently at 655 °C. It was found that ErPO₄ and NaEr(PO₃)₄ form a section which is a real system only in the subsolidus region (below 646 °C). Two ternary invariant points (one ternary peritectic and one ternary eutectic) occur in the investigated partial system ErPO₄–NaPO₃–Er(PO₃)₃.     

An investigation of the polythermal diagram of the H2ONa2HPO4Na2SO4 system

The polythermal diagram of the ternary system H₂ONa₂HPO₄Na₂SO₄ has been established, setting up nine isotherms obtained between 0 and 25°C by conductimetric analysis. The solubility domains of the various solid phases have been determined. One eutectic, three stable and one metastable transitional transformations have been observed. Temperature and composition of the eutectic point have been obtained by thermal analysis at constant flow.     

Compound formation,crystal chemistry,and phase equilibria in the system Li3PO4Zn3(PO4)2

The system Li₃PO₄Zn₃(PO₄)₂ contains several new phases and solid solution series, some of which are interconvertible by high-temperature, composition-dependent, phase transitions. Crystal data are given for two of the new phases, α- and β-Li₄Zn(PO₄)₂. The β form appears to be structurally related to γ-Li₃PO₄, but with some cation disorder. The α form is ordered and appears to be structurally related to Li₂Zn₃(SiO₄)₂. The equilibrium phase diagram for this system has been determined.     

Phase equilibria in the system Rb3PO4–Ba3(PO4)2

The system Rb₃PO₄–Ba₃(PO₄)₂ was investigated by thermoanalytical methods, X-ray powder diffraction, ICP, and FT-IR. On the basis of the obtained results its phase diagram was proposed. For this system with one intermediate compound, BaRbPO₄, we found that this compound melts congruently at 1700 °C, exhibits a polymorphic transition at 1195 °C and is high-temperature unstable. Also, the intermediate compound was subject to gradual decomposes to Ba₃(PO₄)₂ (the solid phase) and vaporization (with conversion of phosphorus and rubidium oxides into vapor phase). We also found that Rb₃PO₄ melts congruently at 1450 °C and shows a polymorphic transition at 1040 °C. Regarding Ba₃(PO₄)₂, we have confirmed that it melts congruently at 1605 °C and exhibits a polymorphic transition at 1360 °C.     

New oxyborates in the MgMnBO system

Two new oxyborate compounds were synthesized during a study of the phase relationships between the pinakiolite-ludwigite series of compounds. The structural topologies of these previously unreported materials have been determined experimentally by comparing calculated with observed electron microscope images. Both of these structures are very similar to each other, and also closely related to pinakiolite which consists of flat walls of edge-sharing octahedra connected to zigzag chains of octahedra by triangular BO₃ groups. The two new structures contain similar infinite walls which are separated by slabs of octahedra that are wider than the zigzag chains found in pinakiolite. A new series of structurally related oxyborate compounds can be envisaged and are described.     

Thermo-Raman Studies on Dehydration of Na4P2O7⋅10H2O and Phase Transformations of Na4P2O7

In this work, dehydration of sodium diphosphate decahydrate Na₄P₂O₇⋅10H₂O and phase transformations of Na₄P₂O₇ in open air have been studied in detail by thermo-Raman spectroscopy. The spectra were measured continuously in a temperature range from room temperature up to 600°C for the bands of P₂O₇ ^4- and H₂O. The spectral variation showed one step of dehydration and four-phase transformations. The thermo-Raman intensity(TRI) and differential thermo-Raman intensity (DTRI) curves calculated from the characteristic bands of H₂O also showed one step of dehydration with the loss of all hydrated water in the temperature interval from 45 to 69°C. Thermogravimetric measurements supported this result. The thermo-Raman investigation indicated the transformation of Na₄P₂O₇ from low temperature phase to high temperature phase proceed through pre-transitional region from 75 to 410°C before the major orientational disorder at 418°C and minor structural modifications at 511,540 and 560°C. The results from differential scanning calorimetry and differential thermal analysis on Na₄P₂O₇ showed endotherms at 407,517, 523, 548, 557°C and 426, 528, 534, 555, 565°C, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hydrothermal Synthesis and Structure of a Novel Molybdenum Phosphate: Na4(H3O) [Na(HPO4)2(PO4)4Mo18O49]·16H2O①

The title compound Na5H37P6Mo18O90 1 (Mr=1658) was synthesized under hydrothermal condition and its crystal structure was determined by X-ray diffraction. It crystallized in the monoclinic system, space group P21 with a =14.957(1), b =16.535(1), c = 16.159(1)?,β=108.586(2)°, V=3787.85?3, Dc =3.040g/cm3, Z=2,μ(MoKα)=3.17mm－1, F(000)=3242. The final R and wR are 0.0500 and 0.1535 for 6643 observable reflections with I≥2σ(I), respectively. The result of structure analysis indicates that [Na(HPO4)2(PO4)4－Mo18 O49]5－anions 2 in 1 has the symmetry of C2V, in which each MoVIO6 octahedron is connected to adjacent PO4 tetrahedra through corner-sharing and to adjacent octahedra through edge-sharing or corner-sharing.     

LiTi2(PO4)3的Na/Li离子交换特征

锂离子传导材料LiTi₂(PO₄)₃能在LiCl水溶液中高选择性地与Na⁺进行离子交换. 研究了NaCl 溶液中LiTi₂(PO₄)₃上的Na/Li离子交换反应, 实验结果表明, 升高温度能显著提高LiTi₂(PO₄)₃上的Na/Li交换反应速率, 其离子交换动力学规律可近似由JMAK(Johnson-Mehl-Aurami-Kalmogorav)方程描述. 对LiTi₂(PO₄)₃在水和NaCl溶液中的溶解行为的研究结果表明, 升高温度能加快其在水中的溶解速率, pH值过大或过小及离子交换都会加剧LiTi₂(PO₄)₃的溶解.     

NH4VO3在NH4H2PO4-H2O和(NH4)3PO4-H2O体系中的溶解度

采用等温溶解法测定了偏钒酸铵(NH₄VO₃)在NH₄H₂PO₄-H₂O和(NH₄)₃PO₄-H₂O体系中T = 298.15-328.15 K时的溶解度以及溶液的密度和pH值。结果表明, NH₄VO₃的溶解度随着(NH₄)₃PO₄或NH₄H₂PO₄溶液浓度的增大,先降低后升高,这是由于同离子效应、化学反应平衡及离子活度的共同作用。比较T = 298.15K时, NH₄VO₃分别在NH₄H₂PO₄-H₂O、(NH₄)₂HPO₄-H₂O和(NH₄)₃PO₄-H₂O体系中溶解度,发现在相同的磷酸盐浓度下, NH₄VO₃的溶解度在NH₄H₂PO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在(NH₄)₂HPO₄-H₂O体系中最小。进一步地,在T = 298.15 K和磷酸盐浓度C = 0.5 mol·kg^-1时,结合pH值和反应溶度积常数K_SP等计算三个体系中的平均离子活度系数(γ_±),发现γ_±值在(NH₄)₂HPO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在NH₄H₂PO₄-H₂O体系中最小,与溶解度规律一致。     

Na3V2(PO4)2O2F的合成及其在钠离子电池中的应用

目前,合成Na3V2(PO4)2O2F(NVPF)材料的方法包括高温固相法、水热法、溶剂热法等,这些方法均不利于该材料的大规模工业化生产.本文开发了温和的低温共沉淀法合成NVPF材料,该材料首次放电容量为105.6 mAh·g-1,首次效率为90.16％.经过简单的热处理过程,可以有效去除由于液相合成带来的结晶水以及吸...     

A Novel Copper Ammonium Diphosphate--Dimorphic Cu 3 (NH 4 ) 2 (P 2 O 7 ) 2 ·3H 2 O

This article deals with the insoluble compounds, formed in CuSO 4 -(NH 4 ) 4 P 2 O 7 -H 2 O system. The solutions were analyzed by means of chemical analysis, the precipitate--by means of x-ray diffraction, chemical and thermal analysis, and FTIR spectroscopy. We have established that at least three poorly soluble compounds can form in the system CuSO 4 -(NH 4 ) 4 P 2 O 7 -H 2 O. Their chemical formulae are Cu 2 P 2 O 7 ;5H 2 O and polymorphic Cu 3 (NH 4 ) 2 (P 2 O 7 ) 2 ;3H 2 O. The first modification is most stable when |Cu + P 2 O 7 | = 0.25 M ( n = 1.0), and, in a matter of days, Dimorph A transforms to Dimorph B, which has not been described in any publications.     

新型杂多化合物[(CH3CH2)4N]4H3O· {Na[(HMo2O5)3(HPO4)(H2PO4)3]2}·(H2PO4)2·10H2O的水热合成与晶体结构

杂多化合物在催化、医药、材料及光化学等方面具有广泛的应用前景 [1～ 4 ] ,其中钼磷多金属氧酸盐具有优异的氧化催化性能 [5,6 ] .近年来合成的新奇结构的钼磷多金属氧酸盐中已测定结构的有含帽[7,8] 和非帽[9～ 12 ] 系列 .本文利用水热法合成了未见文献报道的结构新颖的夹心型磷钼多金属氧酸盐[( CH3CH2 ) 4N]4 H3O{Na[( HMo2 O5) 3( HPO4 ) ( H2 PO4 ) 3]2 }· ( H2 PO4 ) 2 · 1 0 H2 O,并测定了其晶体结构 .1　实验与晶体结构分析1 .1　仪器与试剂　元素 Na用美国原子吸收分光光度计测定 ;C,H和 N用 Perkin- Elmer 2 4 0…     

Raman spectroscopy of newberyite Mg(PO3OH)·3H2O: a cave mineral

Newberyite Mg(PO3OH)·3H2O is a mineral found in caves such as from Moorba Cave, Jurien Bay, Western Australia, the Skipton Lava Tubes (SW of Ballarat, Victoria, Australia) and in the Petrogale Cave (Madura, Eucla, Western Australia). Because these minerals contain oxyanions, hydroxyl units and water, the minerals lend themselves to spectroscopic analysis. Raman spectroscopy can investigate the complex paragenetic relationships existing between a number of 'cave' minerals. The intense sharp band at 982 cm(-1) is assigned to the PO4(3-)ν1 symmetric stretching mode. Low intensity Raman bands at 1152, 1263 and 1277 cm(-1) are assigned to the PO4(3-)ν3 antisymmetric stretching vibrations. Raman bands at 497 and 552 cm(-1) are attributed to the PO4(3-)ν4 bending modes. An intense Raman band for newberyite at 398 cm(-1) with a shoulder band at 413 cm(-1) is assigned to the PO4(3-)ν2 bending modes. The values for the OH stretching vibrations provide hydrogen bond distances of 2.728 ? (3267 cm(-1)), 2.781 ? (3374 cm(-1)), 2.868 ? (3479 cm(-1)), and 2.918 ? (3515 cm(-1)). Such hydrogen bond distances are typical of secondary minerals. Estimates of the hydrogen-bond distances have been made from the position of the OH stretching vibrations and show a wide range in both strong and weak bonds.     

The thermal transformation of Na LiA zeolites. A new polymorph in the system Li2OAl2O3SiO2

High-temperature phase transformations of A zeolite with various degrees of exchange of Na⁺ with Li⁺ ions were investigated. An increase in the number of Li⁺ ions per unit cell accelerates the thermal transformation of the zeolite framework to the amorphous state. Above 730°C, four phases (carnegieite, nepheline, β-eucryptite, and a new phase—γ-eucryptite) were identified. Only γ- and β-eucryptite phases were obtained from pure LiA zeolite. γ-eucryptite is a new metastable polymorph in the system Li₂OAl₂O₃SiO₂. γ-eucryptite a₀ = 7.231(3)Å, b₀ = 10.270(6) Å, c₀ = 12.054(7) Å) is transformed to β-eucryptite (a₀ = 10.533(5) Å, c₀ = 11.148(5) Å) above 840°C.     

The synthesis and crystal structure of a hydrated magnesium phosphate Mg3(PO4)2·4H2O

The synthesis and crystal structure of a novel hydrated magnesium phosphate is described. The crystal structure was solved from powder X-ray diffraction data. Mg₃(PO₄)₂·4H₂O crystallizes in the orthorhombic space group Cmc2₁ (No. 36) with a=8.41087(9) Å, b=17.3850(2) Å, c=12.8034(1) Å, V=1872.15(4) ų and Z=8. The structure consists of sheets stacked along [010], which are linked by edge sharing octahedral Mg₂O₆(H₂O)₄ dimers. Within the sheets there are infinite edge-sharing chains of Mg octahedra along [100]. The compound has been further characterized by ³¹P MAS NMR spectroscopy and thermogravimetric analysis. The crystal structure of two dehydrated variants existing around 200 (Mg₃(PO₄)₂·2.5H₂O) and 275 °C (Mg₃(PO₄)₂·2H₂O) remain unknown.     

K3[Fe3.26V0.74(OH)O(PO4)4(H2O)2]·2H2O: a synthetic leucophosphite

A new iron(III)/vanadium(III) phosphate, K₃[Fe_3.26V_0.74(OH)O(PO₄)₄(H₂O)₂]·2H₂O (1), has been obtained by hydrothermal synthesis and characterized by single crystal X-ray diffraction, Scanning electron microscopy–energy dispersive X-ray spectroscopy, Inductively coupled plasma atomic emission spectroscopy (ICP), thermogravimetric analysis, and FTIR spectroscopy. Single crystal X-ray diffraction reveals a 3D open framework (monoclinic, space group P2₁/n, a?=?9.6391(7)?Å, b?=?9.8063(7)?Å, c?=?9.7268(7)?Å, β?=?100.71(1)°, and V?=?903.38(11)?ų). This structure presents Fe^III and V^III in a 4.4?:?1?M ratio with the metal ions in two different crystallographic sites. Both metallic centers have distorted octahedral environments, linked by PO₄ tetrahedra, forming channels along the a-axis. The asymmetric unit of K₃[Fe_3.26V_0.74(OH)O(PO₄)₄(H₂O)₂]·2H₂O presents a {M₄(OH)O(PO₄)₄(H₂O)₂}^3? anionic entity, charge balanced by three K⁺, which are located within the channels. It is also possible to distinguish M₄O₂ units whose M^III polyhedra are linked by vertex and edges.     

Phase formation along the PO 4 3− /Zr = 1.5–2.0 section of the ZrO(NO3)2-KF-H3PO4-H2O) system

The phase composition of precipitates at 20°C along the PO ₄ ^3? /Zr = 1.5–2.0 section at KF/Zr = 1–5 (mol/mol) of the ZrO(NO₃)₂-H₃PO₄-KF-H₂O system has been investigated. Phases in these precipitates have been identified by X-ray powder diffraction, crystal-optical, chemical, and thermal analyses and by IR spectroscopy. The previously known potassium zirconates K₃ZrF₇ and K₂ZrF₆ have been revealed, and crystalline fluorophosphate zirconate K₃Zr₃F₃(HPO₄)₃(PO₄)₂ and a phosphate nitrate of unknown formula have been obtained for the first time.     

Hydrothermal synthesis and structure determination of Ag3(VVO2){O3PCH2PO3} or MIL-42: a new vanadium(V) methylendiphosphonate inserting silver cations

A new formulated compound, Ag₃(V^VO₂){O₃PCH₂PO₃} or MIL-42, was synthesized hydrothermally at 170 °C. It crystallizes in the monoclinic system (space group P2₁/n (n°14)) with lattice parameters a=8.9404(2) Å, b=8.0226(2) Å, c=11.7395(1) Å and β=100.720(1)°, V=827.32(3) ų, Z=4. Its structure was determined from single crystal X-ray diffraction data (R₁(F_o)=0.0231, wR₂(F_o²)=0.0588 for 2126 unique reflections with I≥2σ(I)). MIL-42 is three-dimensional with one-dimensional chains of corner linked trimeric units related by sheets of Ag⁺ in tetrahedral and five-fold coordination. The chains are built up from V^VO₅ trigonal bipyramids; one edge of their equatorial plane is chelated by one methylendiphosphonate group. The silver sheets are built up from corner-sharing hexamers in which silver exhibits tetrahedral and five-fold coordination.