Structure and luminescence properties of silver-doped NaY(PO3)4 crystal

Single crystals of NaY(PO₃)₄ and Ag_0.07Na_0.93Y(PO₃)₄ have been synthesized by flux method. These new compounds turned out to be isostructural to NaLn(PO₃)₄, with Ln=La, Nd, Gd and Er [monoclinic, P2₁/n, a=7.1615(2) Å, b=13.0077(1) Å, c=9.7032 (3) Å, β=90.55 (1)°, V=903.86(14) Å³ and Z=4]. The structure is based upon long polyphosphate chains running along the shortest unit-cell direction and made up of PO₄ tetrahedra sharing two corners, linked to yttrium and sodium polyhedra. Infrared and Raman spectra at room temperature confirms this atomic arrangement. The luminescence of silver ions was reported in metaphosphate of composition Ag_0.07Na_0.93Y(PO₃)₄. One luminescent centre was detected and assigned to single Ag⁺ ions.     

一种新型的一维杂化磷酸锌化合物(2,2′-bipy)2·Zn2(PO4H)(PO4H2)2的合成与结构表征

作为磷酸盐基空旷骨架(Open-framework)化合物的一个重要组成部分, 磷酸锌基空旷骨架化合物经过近10年的发展已经成为内涵丰富的一个族系[1～6]. 实验证明有机胺基团可以作为配体, 起到电荷平衡阳离子与磷酸锌构成骨架作用[1～6]. 我们认为, 有机胺和骨架上的部分锌原子键合方式与多金属氧酸盐中的配体-次级金属结构模型存在相似性. 因此, 将多金属氧酸盐的配体-次级金属模型向过渡金属磷酸盐领域进行"嫁接", 不仅存在着实验参考依据[3,4], 而且将会推动磷酸盐配位化学的发展. 与多面体构成的钼酸盐和钒酸盐相比较, 这种"嫁接"意味着以磷氧四面体为结构单元的过渡金属磷酸盐可能存在着新颖的拓扑结构. 我们选用2,2′-联吡啶作为螯合配体, 制备新颖的具有杂化磷酸锌骨架的化合物, 并通过刚性配体的空间效应在一定程度上限制磷酸锌聚合体的外延连接. 本文报道一种一维链状杂化磷酸盐(2,2′-bipy)2Zn2(PO4H)(PO4H2)2(以下简称FJ-10, FJ: Fujian Institute of Research on the Structure of Matter)的水热合成及单晶结构表征. 在磷酸锌体系中, FJ-10具有新颖的骨架拓扑结构和堆垛方式. 我们将对此类化合物的合成、结构与性质进行系列报道.     

Crystal structure and luminescence property of novel three-dimensional network of {Eu2(p-BDC)3(Phen)2(H2O)2}n

The single crystal of a supramolecule, {Eu₂(p-BDC)₃(Phen)₂(H₂O)₂}_n (p-BDC=1,4-benzenedicarboxylate), with characteristic luminescence of Eu³⁺ was obtained by means of soft chemistry. The crystal structure determination reveals that each Eu³⁺ ion is coordinated by five oxygen atoms of p-BDC anions, one oxygen atom from water molecule, and two nitrogen atoms of Phen, respectively, resulting in an eight-coordinated Eu³⁺ center and a distorted square antiprism coordination polyhedron. Four bridges, two carboxylates of μ₄-p-BDC and two of μ₃-p-BDC, connect two Eu atoms into a binuclear unit. Moreover, the μ₃-p-BDC integrates the binuclear building blocks at the direction of b axis and the μ₄-p-BDC polymerizes the structure roughly along the direction of the sum vector of axis b and c, respectively, forming two-dimensional layers. Hydrogen bonds between layers make the structure a three-dimensional network. The luminescence spectra measured under 77 K demonstrate the antenna effect of Phen and the ⁵D₁→⁵D₀ energy transfer path within Eu³⁺ ion. Both luminescence spectra and crystal structure lead to the conclusion that the local symmetry around the Eu³⁺ ion is C₁ and that more than one Eu³⁺ ion sites having slight environmental difference are present.     

Thermochemistry of the mixed calcium phosphate Ca8P2O7(PO4)4

The calcium mixed phosphate Ca₈P₂O₇(PO₄)₄ has been synthesized by thermal decomposition of octacalcium phosphate previously prepared by precipitation in ammoniacal phosphate solution. The enthalpy of formation at 298.15 K referenced to β-tricalcium phosphate and calcium pyrophosphate is determined. β-Tricalcium phosphate was prepared by two methods: precipitation in ammoniacal aqueous medium and high temperature solid-state reaction. Calcium pyrophosphate was prepared by high temperature solid-state reaction. All the compounds are characterized by chemical analysis, X-rays diffraction and IR spectroscopy. The enthalpy of formation +10.83 ± 0.63 kJ mol⁻¹ is obtained by solution calorimetry at 298.15 K in nitric acid.     

Hydrothermal synthesis and structures of the novel niobium phosphates [NbOF(PO4)](N2C5H7) and [(Nb0.9V1.1)O2(PO4)2(H2PO4)](N2C2H10)

Two new niobium phosphates were synthesized and their crystal structures determined from single-crystal X-ray data. [NbOF(PO₄)](N₂C₅H₇) (1) (monoclinic, space group P2₁/c, a=11.442(1), b=9.1983(7), c=9.1696(8) Å, β=109.94(1)°) has a layered structure and is the first example of a negatively charged NbOF(PO₄) layer analogous to the MO(H₂O)PO₄ (M=V, Nb) layers. The layer charge is compensated by interlayer 4-aminopyridnium cations that adopt an unusual arrangement as a consequence of H-bonding and π-π interactions. The interlayer aminopyridnium cations can be exchanged with alkylammonium ions which form bilayers inclined at ∼65° to the NbOF(PO₄) layer. [(Nb_0.9V_1.1)O₂(PO₄)₂(H₂PO₄)] (N₂C₂H₁₀) (2) (orthorhombic, space group Pbca, a=15.821(2),b=9.0295(9),c=18.301(2) Å) has a disordered three-dimensional structure based on NbO(PO₄) layers cross-linked by phosphate tetrahedra, and has a similar structure to the known vanadium analog [V₂O₂(PO₄)₂(H₂PO₄)] (N₂C₂H₁₀).     

Structural changes accompanying negative thermal expansion in Zr2(MoO4)(PO4)2

Zr₂(MoO₄)(PO₄)₂ is orthorhombic (Sc₂W₃O₁₂ structure) from 9 to at least 400 K, and shows anisotropic volume negative thermal expansion (α_a=−8.35(4)×10⁻⁶ K⁻¹; α_b=3.25(3)×10⁻⁶ K⁻¹; α_c=−8.27(5)×10⁻⁶ K⁻¹ in the range 122-400 K) similar in magnitude to A₂M₃O₁₂ (M—Mo or W) with large A³⁺. The contraction on heating is associated with a pattern of Zr-O-Mo/P bond angle changes that is somewhat similar, but not the same as that for Sc₂W₃O₁₂. On heating, the most pronounced reductions in the separation between the crystallographic positions of neighboring Zr and P are not associated with significant reductions in the corresponding Zr-O-P crystallographic bond angles, in contrast to what was seen for Sc₂W₃O₁₂.     

Synthesis, structure, and properties of the first trimetallic phosphate [Ni(H2O)4]Cd(VO)(PO4)2 with neutral 3-D pillared-layer framework

Hydrothermal reactions of VOSO₄·3H₂O, CdAc₂·2H₂O, NiCl₂·6H₂O, H₃PO₄, and H₂O yield the first example of trimetallic phosphate materials, [Ni(H₂O)₄]Cd(VO)(PO₄)₂1. The single-crystal X-ray diffraction shows that its structure consists of Cd/V/O binary metal oxide lamellas decorated by PO₄ tetrahedra, which are further pillared by NiO₂(H₂O)₄ octahedra to generate a neutral 3-D framework containing two intercrossing 8-MR channels where the coordinated water molecules protrude into. Thermal and magnetic behaviors of this material were also measured. Crystal data: CdNiVP₂O₁₃H₈, orthorhombic Ibca (No.73), a=7.1307(2) Å, b=18.6248(3) Å, c=14.8046(2) Å, V=1966.17(7) Å³, Z=8.     

A crystal structure of mixed-metal dianionic phosphate Cs3.70Mg0.60Ti2.78(TiO)3(P2O7)4(PO4)2

The single crystals of caesium magnesium titanium (IV) tri-oxo-tetrakis-diphosphate bis-monophosphate, Cs_3.70Mg_0.60Ti_2.78(TiO)₃(P₂O₇)₄(PO₄)₂, crystallize in sp. gr. P-1 (No. 2) with cell parameters a=6.3245(4), b=9.5470(4), c=15.1892(9) Å, α=72.760(4), β=85.689(5), γ=73.717(4), z=1. The titled compound possesses a three-dimensional tunnel structure built by the corner-sharing of distorted [TiO₆] octahedra, [Ti₂O₁₁] bioctahedra, [PO₄] monophosphate and [P₂O₇] pyrophosphate groups. The Cs⁺ cations are located in the tunnels. The partial substitution of Ti positions with Mg atoms is observed. The negative charge of the framework is balanced by Cs cations and Mg atoms leading to pronounced concurrency and orientation disorder in the [P₂O₇] groups, which coordinate both.     

Crystal structure and phase transformations of calcium yttrium orthophosphate, Ca3Y(PO4)3

Crystal structure and phase transformations of calcium yttrium orthophosphate Ca₃Y(PO₄)₃ were investigated by X-ray powder diffraction, selected-area electron diffraction, transmission electron microscopy and optical microscopy. The high-temperature phase is isostructural with eulytite, cubic (space group ) with a=0.983320(5) nm, V=0.950790(8) nm³, Z=4 and D_x=3.45 Mg m⁻³. The crystal structure was refined with a split-atom model, in which the oxygen atoms are distributed over two partially occupied sites. Below the stable temperature range of eulytite, the crystal underwent a martensitic transformation, which is accompanied by the formation of platelike surface reliefs. The inverted crystal is triclinic (space group P1) with a=1.5726(1) nm, b=0.84267(9) nm, c=0.81244(8) nm, α=109.739(4)°, β=90.119(5)°, γ=89.908(7)°, V=1.0134(1) nm³, Z=4 and D_x=3.24 Mg m⁻³. The crystal grains were composed of pseudo-merohedral twins. The adjacent twin domains were related by the pseudo-symmetry mirror planes parallel to with the composition surface . When the eulytite was cooled relatively slowly from the stable temperature range, the decomposition reaction of Ca₃Y(PO₄)₃→β-Ca₃(PO₄)₂+YPO₄ occurred.     

Magnetic and vibrational properties and crystal structure of Sr9.2Co1.3(PO4)7 with disordered arrangements of some strontium, cobalt, and phosphate ions

Solid solutions of Sr_9+xCo_1.5−x(PO₄)₇ were found in the compositional range of 0.05?x?0.30. The structure of Sr_9.2Co_1.3(PO₄)₇ (x=0.2) was determined from single crystal X-ray diffraction (space group (No. 166); Z=3; and ; ; ; ) and refined to R₁=0.0343 and wR₂=0.0633 for 586 reflections with I>2σ(I). Sr_9.2Co_1.3(PO₄)₇ is structurally related to β-Ca₃(PO₄)₂ and Sr₃(PO₄)₂ and has disordered arrangements of some Sr²⁺, Co²⁺, and PO₄³⁻ ions. Sr²⁺ ions at a 9e site are statistically disordered among four positions near the center of symmetry. Co²⁺ and Sr²⁺ ions are split along the c-axis to occupy a 6c site that is 75% vacant. The P1O₄ tetrahedra are orientationally disordered. Sr²⁺ ions at an 8-fold coordinated 18h site, Co²⁺ ions at an octahedral 3a site, and the P2O₄ tetrahedra are ordered in the structure of Sr_9.2Co_1.3(PO₄)₇. Features of Raman spectra are discussed in relation to the crystallographic structure of Sr_9.2Co_1.3(PO₄)₇ and in comparison with Raman spectra of β-Ca₃(PO₄)₂-type and Sr₃(PO₄)₂-type compounds. Sr_9.2Co_1.3(PO₄)₇ is paramagnetic between 2 and 300 K with an effective magnetic moment of 4.98μ_B per Co²⁺ ion.     

Synthesis and characteristics of a novel 3-D organic amine oxalate: (enH2)1.5[Bi3(C2O4)6(CO2CONHCH2CH2NH3)]·6.5H2O

A novel 3-D compound of (enH₂)_1.5[Bi₃(C₂O₄)₆(CO₂CONHCH₂CH₂NH₃)]·6.5H₂O has been hydrothermally synthesized and characterized by IR, ultraviolet-visible diffuse reflection integral spectrum (UV-Vis DRIS), fluorescence spectra, TGA and single crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with , , , β=112.419(3)°, , Z=8, R₁=0.0463 and wR₂=0.1393 for unique 7686 reflections I>2σ(I). In the title compound, the Bi atoms have eight-fold and nine-fold coordination with respect to the oxygen atoms, with the Bi atoms in distorted dodecahedron and monocapped square antiprism, respectively. The 3-D framework of the title compound contains channels and is composed of linkages between Bi atoms and oxalate units, forming honeycomb-like layers with two kinds of 6+6 membered aperture, and pillared by oxalate ligands and monamide groups. The channels have N-ethylamine oxalate monamide group ⁻CO₂CONHCH₂CH₂NH₃⁺, which is formed by the in situ reaction of en and oxalate acid. At room temperature, the complex exhibits intense blue luminescence with an emission peak at 445 nm.     

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).     

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.     

New open-framework in the uranyl vanadates A3(UO2)7(VO4)5O (A=Li, Ag) with intergrowth structure between A(UO2)4(VO4)3 and A2(UO2)3(VO4)2O

New uranyl vanadates A₃(UO₂)₇(VO₄)₅O (M=Li (1), Na (2), Ag (3)) have been synthesized by solid-state reaction and their structures determined from single-crystal X-ray diffraction data for 1 and 3. The tetragonal structure results of an alternation of two types of sheets denoted S for _∞²[UO₂(VO₄)₂]⁴⁻ and D for _∞²[(UO₂)₂(VO₄)₃]⁵⁻ built from UO₆ square bipyramids and connected through VO₄ tetrahedra to _∞¹[U(3)O₅-U(4)O₅]⁸⁻ infinite chains of edge-shared U(3)O₇ and U(4)O₇ pentagonal bipyramids alternatively parallel to a- and b-axis to construct a three-dimensional uranyl vanadate arrangement. It is noticeable that similar _∞[UO₅]⁴⁻ chains are connected only by S-type sheets in A₂(UO₂)₃(VO₄)₂O and by D-type sheets in A(UO₂)₄(VO₄)₃, thus A₃(UO₂)₇(VO₄)₅O appears as an intergrowth structure between the two previously reported series. The mobility of the monovalent ion in the mutually perpendicular channels created in the three-dimensional arrangement is correlated to the occupation rate of the sites and by the geometry of the different sites occupied by either Na, Ag or Li. Crystallographic data: 293 K, Bruker X8-APEX2 X-ray diffractometer equipped with a 4 K CCD detector, MoKα, λ=0.71073 Å, tetragonal symmetry, space group P4¯m2, Z=1, full-matrix least-squares refinement on the basis of F²; 1,a=7.2794(9) Å, c=14.514(4) Å, R1=0.021 and wR2=0.048 for 62 parameters with 782 independent reflections with I?2σ(I); 3, a=7.2373(3) Å, c=14.7973(15) Å, R1=0.041 and wR2=0.085 for 60 parameters with 1066 independent reflections with I?2σ(I).     

Dy3+离子掺杂的全色荧光粉Ca9La(PO4)7的制备及发光特性

采用高温固相法合成了Ca₉La(PO₄)₇:Dy³⁺发光材料. 荧光粉的晶体结构和微观尺寸由X射线粉末衍射(XRD)仪和扫描电子显微镜(SEM)测定. 光致激发和发射光谱发光揭示了材料的光学特性. 实验结果显示: Ca₉La(PO₄)₇:Dy³⁺能够有效吸收紫外-可见光(300-460 nm)而被激发, 呈现一系列的吸收峰. 样品在350 nm近紫外光激发下, 有较强的蓝光(481 nm)和黄光(573 nm)两个窄带发射, 混合成优质的白光发射, 该白光色坐标在国际照明委员会(CIE)色品图中分布在无色点D65 (0.313, 0329)周围. 随着掺杂Dy³⁺离子的摩尔分数的增加, 两种发射均发生浓度猝灭现象, Dy³⁺离子的最佳掺杂为0.05(摩尔分数), 电偶极-电偶极相互作用是主要的猝灭机理.     

FeCo2(CO)7(μ3-S)(O[P(SCH2)2]2)的合成与晶体结构

许多化学工作者对单齿膦配体（ＰＰｈ３,ＰＢｕｎ３,ＰＥｔ２Ｐｈ,Ｐ（ＯＥｔ）３,Ｐ（ＯＣ６Ｈ５）３）与母体簇合物ＦｅＣｏ２（ＣＯ）９（μ３－Ｓ）的取代反应进行过详细研究［１－３］,但对双齿膦配体与母体簇合物的取代反应研究报导较少．Ａｉｍｅ［４］合成了含双齿膦配体的簇合物ＦｅＣｏ２（ＣＯ）７（μ３－Ｓ）（Ｐｈ２ＰＣＨ２ＰＰｈ２）,并用１３ＣＮＭＲ和ＩＲ光谱方法对其结构进行了表征．到目前为止,含双齿膦配体的该类簇合物的晶体与分子结构还未见报导．ＲｏｓａｎｎａＲｏｓｓｅｔｔｉ［２］通过研究母体簇合物与…     

Neutron powder diffraction study of the magnetic and crystal structures of SrFe2(PO4)2

The crystal and magnetic structures of SrFe²⁺₂(PO₄)₂ have been determined by neutron powder diffraction data at low temperatures (space group P2₁/c (no. 14); Z=4; a=9.35417(13) Å, b=6.83808(10) Å, c=10.51899(15) Å, and β=109.5147(7)° at 15 K). Two magnetic phase transitions were found at T₁=7.4 K (first-order phase transition) and T₂=11.4 K (second-order phase transition). The transition at T₂ was hardly detectable by dc and ac magnetization measurements, and a small anomaly was observed by specific heat measurements. At T₁, strong anomalies were found by dc and ac magnetization and specific heat. The structure of SrFe₂(PO₄)₂ consists of linear four-spin cluster units, Fe2-Fe1-Fe1-Fe2. Below T₁, the propagation vector of the magnetic structure is k=[0,0,0]. The magnetic moments of the inner Fe1-Fe1 atoms of the four-spin cluster unit are ferromagnetically coupled. The magnetic moment of the outer Fe2 atom is also ferromagnetically coupled with that of the Fe1 atom but with spin canting. The four-spin cluster units form ferromagnetic layers parallel to the [−101] plane, while these layers are stacked antiferromagnetically in the [−101] direction. Spin canting of the outer Fe2 atoms provides a weak ferromagnetic moment of about 1 μ_B along the b-axis. The refined magnetic moments at 3.5 K are 4.09 μ_B for Fe1 and 4.07 μ_B for Fe2. Between T₁ and T₂, a few weak magnetic reflections were observed probably due to incommensurate magnetic order.     

A novel three-dimensional malonate-bridged complex {[Cu4(4,4′- bpy)8(mal)2(H2O)4](ClO4)2(H2O)4(CH3OH)2}n

A novel malonate-bridged copper (II) compound of formula {[Cu₄(4,4′-bpy)₈(mal)₂(H₂O)₄](ClO₄)₂(H₂O)₄(CH₃OH)₂}_n (4,4′-bpy = 4,4′-bipyridine; mal = malonate dianion) has been prepared and structurally characterized by X-ray crystallography. This compound exhibits a novel three-dimensional network being composed of Cu-4,4′-bipyridine layers which are pillared by malonate bridge ligands. The copper(II) ions has two different coordination environment.     

Electronic structure and photoluminescence properties of Eu-activated Ca2BN2F

The electronic structure of undoped and luminescence properties of Eu²⁺-doped Ca₂BN₂F have been investigated. First-principles calculations for Ca₂BN₂F show that the valence band is mainly composed of F and N 2p, B 2s and 2p orbitals, while the Ca 4s and 3d are almost empty, indicating that Ca₂BN₂F is a very ionic compound. The valence band close to the Fermi level is dominated by the N 2p states, and the bottom of the conduction band is determined by the Ca 3d and N/B 3s orbitals. The direct energy gap is calculated to be about 3.1 eV, in fair agreement with the experimental data of ∼3.6 eV derived from the diffuse reflection spectrum. Due to the high degree of ionic bonding of the coordinations of Eu with (N, F) on the Ca sites, Ca₂BN₂F:Eu²⁺ shows strong blue emission with a maximum at about 420 nm upon UV excitation in the absorption range of 330-400 nm.