福建漳州龙海铁染高岭土磁选尾矿的矿物特征分析

对福建龙海红褐色铁染高岭土磁选尾矿进行了提纯,分离出强磁性含铁矿物,并对其进行了X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、穆斯堡尔谱和磁性测试等分析.研究结果表明:该尾矿所含的强磁性含铁氧化物并非文献报道的磁铁矿(Fe3O4),而是磁赤铁矿(γ-Fe2O3).穆斯堡尔谱分析未检测出样品中存在二价铁,结合XRD及磁性分析,表明磁选尾矿的磁性主要由磁赤铁矿引起.磁赤铁矿在福建省境内尚属首次发现.综合考虑该矿区其他伴生矿物的矿物成分、形貌等特征,及其所处的亚热带温暖潮湿性气候环境,确定该矿区具备形成磁赤铁矿的客观地质条件.通过对矿区的高岭土矿物形貌的大量分析,观察到罕见的高岭土形貌——卷曲型双壁或多壁微米管

Lithium manganese(II) diaquaboro-phosphate monohydrate

The title compound, LiMn(H2O)(2)[BP2O8]center dot H2O, is built up of an open framework of helical borophosphate ribbons interconnected by MnO4(H2O)(2) octahedra, forming one-dimensional channels along [001] occupied by Li+ cations and disordered H2O molecules (site occupancy 0.5). The Li cations reside in two partially occupied sites [occupancies = 0.42 (3) and 0.289 (13)] near the helices

从鱿鱼顶骨β-甲壳素合成的丙酰化甲壳素的结晶结构

分别从α 甲壳素 (来源于蟹壳 )和 β 甲壳素 (来源于鱿鱼顶骨 )制备丙酰化甲壳素。丙酰化β 甲壳素的大角X光衍射图出现 2 0个衍射峰 ,而丙酰化α 甲壳素只在 2 0°左右出现弥散峰。发现丙酰化β 甲壳素的结晶属三斜晶系 ,a =7.997,b =1 3.0 67,c =6.31 6(任意单位 ) ,α =98°5 6′ ,β =1 0 4°1 9′,γ =82°2 6′。列表说明了各衍射峰的归属。据分析 ,每个单元晶胞内含一根分子链的 2 .5个葡萄糖残基单元。分子轴为b

On the preparation of single crystals of 11CaO.7Al2O3.CaF2 and the confirmation of its crystal structure

Single crystals of 11CaO . 7Al(2)O(3) . CaF2(C(11)A(7) . CaF2) of 40-120 mu m in size were prepared by a flux evaporation method. The crystals were colorless trigonal tristetrahedrons with a refractive index of 1.601. By the method of single crystal X-ray diffraction it has been confirmed that the C(11)A(7) . CaF2 is cubic, with a = 11.981 Angstrom, space group , Z = 2 and D-X = 2.720 g cm(-3) The calcium atom is coordinated either to six oxygen atoms in an irregular [CaO6] coordination with 2.380 Angstrom, 2.401 Angstrom and 2.502 Angstrom for Ca-O distances or to six oxygen atoms and one fluorine atom in an asymmetric arrangement with 2.816 Angstrom for F-Ca distance. The aluminum atoms are coordinated to four oxygen atoms forming two different AlO4 tetrahedra: (1) the [Al(1)O(2)(4)], with symmetry (4) over bar and Al(1)-O(2) distance 1.745 Angstrom; and (2) the [Al(2)O-4] composed of one Al(2) atom, one O(1) atom and three O(2) atoms, with symmetry 3, Al(2)-O(1) distance = 1.740 Angstrom and Al(2)-O(2) distance = 1.757 Angstrom. Neighboring AlO4 tetrahedra are connected with each other by sharing oxygen atoms resulting in a three dimensional [AlO4] network-the basic framework of the crystal structure of C(11)A(7) . CaF2. (C) 1997 Elsevier Science Ltd

A sodium calcium arsenate, NaCa(AsO(4))

Natural Science and Engineering Research Council (NSERC) of CanadaThe title compound, NaCa(AsO4), was synthesized using a hydrothermal method at 633-643 K. It has a dense structure composed of alternating layers of distorted [CaO6] octahedra and layers of [AsO4] tetrahedra and distorted [NaO6] octahedra, stacked along the a axis. The As, Ca and two O atoms lie on the mirror plane at y = 1/4 (i.e. 4c), while the Na atom lies on an inversion centre (1/2, 1/2, 0) (i.e. 4b). Each distorted [CaO6] octahedron shares four equatorial common O vertices with four neighboring octahedra, forming a layer parallel to (100), whereas each distorted [NaO6] octahedron shares two opposite edges with two neighboring ones, forming a chain running along [010]. Each isolated [AsO4] tetrahedron shares two edges with two different [NaO6] octahedra in one [NaO6] chain and a vertex with another chain. Simultaneously the above [AsO4] tetrahedron located in a four-membered [CaO6] ring shares one edge of its base facet with one [CaO6] octahedron and three corners with three other [CaO6] octahedra of one [CaO6] layer, and the remaining apex is shared with another [CaO6] layer. [NaO6] octahedra and [CaO6] octahedra are linked to each other by sharing edges and vertices

The layered monodiphosphate Li9Ga3(P2O7)3(PO4)2 refined from X-ray powder data

Nonalithium trigallium(III) tris[pyrophosphate(V)] diphosphate(V), Li9Ga3(P2O7)(3)(PO4)(2), has been synthesized by a hydrothermal method and its crystal structure solved from X-ray powder diffraction data using Rietveld analysis. The structure is based on separate layers parallel to (001), consisting of GaO6 octahedra that share corners with PO4 tetrahedra and P2O7 groups. The lithium ions are located in the interstitial space

Rb3PO4W12O36 from X-ray powder data

The crystal structure of trirubidium phosphate dodecatungstate, Rb3PO4W12O36, has been refined from X-ray powder diffraction data using the Rietveld method. The compound was obtained under hydrothermal conditions and is isotypic with K-2.4(H3O) 0.6PO4W12O36. The regular PO4 tetrahedron ((4) over bar 3m symmetry) is surrounded by 12 WO6 octahedra, building the heteropolymetallate anion. By close packing of these heteropolyanionic units, orthogonally intersecting channels are formed where the Rb atoms are located. The alkali metal ion is surrounded by 12 O atoms to give a polyhedron with (4) over bar2. m symmetry

Ammonium iron(III) phosphate(V) fluoride, (NH4)(0.5)[(NH4)(0.375)K0.125]FePO4F, with ammonium partially substituted by potassium

National Natural Science Foundation of China [40472027]The title compound, ammonium potassium iron(III) phosphate fluoride, (NH4)(0.875)K0.125FePO4F, is built from zigzag chains∞{[FeO4F2](7-)}, with Fe3+ in a distorted octahedral coordination, extending along both the [011] and [0ㄒ1] directions. These chains are made up of alternating trans- [FeO4F2] and cis-[FeO4F2] octahedra via shared F-atom corners, and are linked by PO4 tetrahedra, resulting in an open-framework structure with channels along the [010] and [100] directions. There are two crystallographically independent ammonium sites: one in the [010] channels and the other, partially substituted by K+ ions, in the [100] channels. The ammonium in the [010] channels is fixed to the framework via eight hydrogen bonds (six N-H O and two N-H ···F)

Crystal structure of the 1M-modification of caesium gallium(Ⅲ) monohy-drogen triphosphate, 1M-CsGaHP3O10

CsGaHO10P3, monoclinic, P12(1)/n1 (No. 13), a = 8.843(1) Angstrom, b = 4.9523(5) Angstrom, c = 11.084(1) Angstrom,beta = 108.793(6)degrees, V = 459.5 Angstrom(3), Z = 2, R-gt(F) = 0.042, wR(ref)(F-2) = 0.123, T = 295 K

Crystal structure of rubidium tetrachlorogallate, RbGaCl4

Cl4GaRb, orthorhombic, Pnma (No. 62), a = 11.1699(4) Å, b = 7.0882(2) Å, c = 9.3003(4) Å, V = 736.3 Å 3 , Z = 4, R gt(F) = 0.035, wRref(F 2) = 0.071, T = 293 K. Source of material The title compound was synthesized in a hydrochloric acid solution. The reaction was carried out with a mixture of RbCl (2.418 g) and GaCl 3 (obtained from metal gallium, 1.05g, dissolved in HCl) with the molar ratio of 4:3 adding excess of HCl (37%) in aqueous solu-tions. All starting materials were of analytical grade purity and used without further purification. The mixture was heated to the boiling point on an electric stove, then cooled down to the room temperature. Colorless crystals were grown up after vaporizing for 5 days in air