铈及氟铈联用对CaHPO_4·2H_2O在水溶液中的转化产物的影响

以XRD和IR为表征手段 ,以恒pH法为溶解实验方法 ,研究了 37℃下以铈单独处理和氟铈联用处理对二水磷酸氢钙 (CaHPO4 ·2H2 O ,DCPD)的水化产物及其溶解性质的影响。Ce3 不能促进DCPD向磷灰石转化 ,氟铈联用可加快DCPD的转化。随着Ce3 浓度的提高 ,DCPD经含Ce溶液单独处理后的产物主要为CaHPO4 (DCPA) Ce(PO4 )和Ce(PO4 )。DCPD经氟铈联用处理后的产物主要为DCPA (Ca2 ,Ce3 ) 1 0 -x(PO4 ) 6 -yF2 (F Ce HAP) Ce(PO4 )和F Ce HAP Ce(PO4 )。经 1?Cl3溶液单独处理后的DCPD的抗酸能力已有显著提高。氟铈联用促进溶解度更低的F Ce HAP的形成 ,因此效果优于铈单独处理 ,有可能成为一种有效的防龋方法。     

ASb2(SO4)2(PO4) (A = H3O+, K,Rb): Layered Structure Containing Ordered Sulfate and Phosphate Anions

Three compounds ASb₂(SO₄)₂(PO₄) (A = H₃O⁺, K, Rb) were obtained from the reactions of Sb₂O₃, A₂CO₃ (A = Li, Rb) or K₂SO₄ and NH₄H₂PO₄ in H₂SO₄ (98 %) at 220–250 °C. Their structures were determined by single‐crystal X‐ray diffraction. All compounds crystallize in the triclinic space group P$\bar{1}$ (no.2) and are isostructural. The crystal structures consist of two‐dimensional ²_∞[Sb₂(SO₄)₂(PO₄)]^– anionic layers and alkali cations, which are located between anionic layers. The anionic layers are composed of [SbO₄] ψ‐trigonal bipyramids, [SbO₅] ψ octahedra, [SO₄] tetrahedra, and [PO₄] tetrahedra. All compounds are characterized by solid state UV/Vis/NIR diffuse reflectance spectra, FT‐IR spectroscopy, and Raman spectroscopy.     

Crystal structures of Th(OH)PO4, U(OH)PO4 and Th2O(PO4)2. Condensation mechanism of MIV(OH)PO4 (M = Th,U) into M2O(PO4)2

Three new crystal structures, isotypic with β-Zr₂O(PO₄)₂, have been resolved by the Rietveld method. All crystallize with an orthorhombic cell (S.G.: Cmca) with a = 7.1393(2) Å, b = 9.2641(2) Å, c = 12.5262(4) Å, V = 828.46(4) Å³ and Z = 8 for Th(OH)PO₄; a = 7.0100(2) Å, b = 9.1200(2) Å, c = 12.3665(3) Å, V = 790.60(4) Å³ and Z = 8 for U(OH)PO₄; a = 7.1691(3) Å, b = 9.2388(4) Å, c = 12.8204(7) Å, V = 849.15(7) Å³ and Z = 4 for Th₂O(PO₄)₂. By heating, the M(OH)PO₄ (M = Th, U) compounds condense topotactically into M₂O(PO₄)₂, with a change of the environment of the tetravalent cation that lowers from 8 to 7 oxygen atoms. The lower stability of Th₂O(PO₄)₂ compared to that of U₂O(PO₄)₂ seems to result from this unusual environment for tetravalent thorium.     

磷酸钡钙:铈、锰红色荧光粉的研制

采用高温固相反应合成了磷酸钡钙：铈、锰红色荧光粉. 借助TG, XRD, 荧光粉相对亮度仪、荧光分光光度仪等手段系统研究了合成过程中原料化学组成及配比、合成条件对磷酸钡钙：铈、锰发光性能的影响. 结果表明, 荧光粉基质 （BaxCa1-x）3（PO4）2具有畸变的Ca3（PO4）2结构. 该荧光粉中Ce^3＋是助激活剂, Mn^2＋是激活剂, 由Ce3＋→Mn^2＋ 的能量传递使Mn^2＋激发产生650 nm左右的发射, 当Ce^3＋和Mn^2＋浓度相等且都为0.15时, 荧光粉有最高的红色发射亮度.     

具有新结构类型的化合物Csln[PO3(OH)]2的合成与结构

水热法合成了新结构类型化合物CsIn[P03(0H)]2,并通过单晶X-射线衍射表征结构.标题化合物空间群为P121/c1(No.14),晶体学参数为:M=439.69,mP56,a=0.532 86(6)nm,b=0.91653(7)nm,c=1.478 39(14)nm,β=93.849(9).,V=0.7204(1)nm3,Z=4,Dx=4.054 g·cm-3,μ=8.713 mm-1,F(000)=800,R1= 0.0325,wR2=0.0874.在该化合物中,2个In06八面体和4个PO4四面体形成交连的六元环柱,并沿a轴方向形成近六方密堆积并连接成Cs+离子占据的十二元环结构隧道,六元环和十二元环连接构筑了三维网络结构.与类似化学计量比化合物Na2In2[PO3(0H)]4·H2O比较,标题化合物中十二元环的形成明显取决于隧道阳离子的大小,其拓扑构造可看作扩展的6,3-网格连接,化合物RbIn[PO3(0H)]2与之同构.     

Hydrothermal Synthesis and Structure of a New Molybdenum Phosphate: (NH_3CH_2CH_2NH_3)_(2.5)[Mo_5O_(15)(PO_4) (HPO_4)]·7.5H_2O

1 INTRODUCTION A new class of materials of metal oxide clusters based on anionic molybdenum phosphate frameworks has received much attention as a consequence of their potential applications in catalysis and materials science [1]. As a result, some molybdenum phosphates have been studied [2,3]. Recently we have studied the structure of NaPMO material[4] and the spectrum of multicomponent compound with Keggin struc- ture [5]. Here we report the synthesis and crystal structure of a new…     

Lone-Pair Enhanced Birefringence in an Alkaline-Earth Metal Tin(II) Phosphate BaSn2(PO4)2

The first alkaline-earth metal tin(II) phosphate, BaSn₂(PO₄)₂, has been discovered, which consists of layered structures constructed from strictly alternating [SnO₃]⁴⁻ and [PO₄]³⁻ moieties. This compound is expected to have a large birefringence with Δn≈0.071 at 1064 nm, owing to the presence of stereochemically active lone pair metal cations.     

Hydrothermal Synthesis and Crystal Structure of a Three-dimensional Compound {Mn（H2O）4（VO）2（PO4）2}n

1 INTRODUCTION Current research interest is focused on the designof structures built up from octahedral and tetrahedralbuilding blocks[1]. During the wide investigations intransition-metal phosphates for many years, a num-ber of new mixed transition-metal phosphates havebeen reported[2]. A great number of manganese phos-phates were largely discovered as minerals[1]. On theother hand, many vanadium phosphates have alsobeen prepared recently partly because of their poten-tial applications …     

A first Mn member in the struvite morphotropic series,CsMn(H2O)6(PO4): hydrothermal synthesis,crystal structure and interconnections within the family of related phosphates

Caesium manganese hexahydrate phosphate, CsMn(H₂O)₆(PO₄), was synthesized under hydrothermal conditions. Its crystal structure was determined from single‐crystal X‐ray diffraction data. The novel phase crystallizes in the hexagonal space group P6₃mc and represents the first manganese member in the struvite morphotropic series, AM(H₂O)₆(TO₄). Its crystal structure is built from Mn(H₂O)₆ octahedra and PO₄ tetrahedra linked into a framework via hydrogen bonding. The large Cs atoms are encapsulated in the framework cuboctahedral cavities. It is shown that the size of the A⁺ ionic radius within the morphotropic series AM(H₂O)₆(XO₄) results is certain types of crystal structures and affects the values of the unit‐cell parameters. Structural relationships with Na(H₂O)Mg(H₂O)₆(PO₄) and the mineral hazenite, KNa(H₂O)₂Mg₂(H₂O)₁₂(PO₄)₂, are discussed.     

Two new open framework cobalt phosphates: NaCo3(OH)(PO4)2.1/4H2O and Na(NH4)Co2(PO4)2.H2O

Two new cobalt phosphates, NaCo₃(OH)(PO₄)₂.1/4H₂O (1) and Na(NH₄)Co₂(PO₄)₂.H₂O (2) have been synthesized hydrothermally and characterized by single crystal X-ray diffraction methods, vibrational (IR and Raman) spectroscopy, thermogravimetric analysis and magnetic measurements. The structure of 1 is a new framework type while 2 is an example of a chiral cobalt phosphate. Both phases contain channels in which the Na⁺, NH₄⁺ cations and H₂O molecules are located.     

一种新颖层状磷酸镓化合物[Ga3(PO4)4](H3NCH2CH2)2NH2的合成与结构表征

晶体结构;水热合成;一种新颖层状磷酸镓化合物[Ga3(PO4)4](H3NCH2CH2)2NH2的合成与结构表征     

Raman spectroscopic study of the uranyl minerals vanmeersscheite U(OH)4[(UO2)3(PO4)2(OH)2].4H2O and arsenouranylite Ca(UO2)[(UO2)3(AsO4)2(OH)2].(OH)2.6H2O

Raman and infrared spectra of secondary uranyl phosphate vanmeersscheite and Raman spectrum of secondary uranyl arsenate arsenuranylite were recorded and interpreted, and the spectra related to the structure of the minerals. Observed bands were attributed to the stretching and bending vibrations of uranyl, phosphate and/or arsenate units and OH (H(2)O and OH(-)) units. Phosphuranylite sheet topology is characteristic for both minerals. U-O bond lengths in uranyl were calculated from the spectra and compared with those inferred for vanmeersscheite from the X-ray single crystal structure analysis. O-H...O hydrogen bonds in both minerals were also inferred using the Libowitzky empirical relation.     

新型磷酸钒孔道结构化合物(H3NCH2CH2NH3)3- [ (VO)4(PO4)2 (HPO4)4]的水热 合成及结构表征

以有机分子乙二胺作为模板剂合成了新型磷酸钒孔道化合物(H3NCH2CH2NH3)3^-[(VO)4(PO4)2(HPO4)4,并通过X射线单晶衍射实验进行了结构表征,晶体学数据为：C2/c,a=1.8505(9)nm,b=0.7089(4)nm,c=2.3304(10)nm,β=96.43(3)°,V-3.038(3)nm^3,Z=8,R=0.067,Rw^b=0.1635,该化合物具有非常独特和规整的二维孔道骨架结构,进一步的晶体化学研究表明该化合物为一新的VPO物相。