Crystal structure of KSb2PO8

KSb₂PO₈ crystallizes in the monoclinic system, space group Co, with $\text{a}\text{= 12.306(4)}\text{A}\text{?}$, $\text{b}\text{= 7.086(2)}\text{A}\text{?}$, $\text{c}\text{= 15.037(5)}\text{A}\text{?}$, β = 95.82(3)°, Z = 8. The structure was determined from 2149 reflexions collected on a NONIUS CAD4 automatic diffractometer with MoK$\text{}\text{?}$ga radiation. The final R index and weighted R_w index are 0.019 and 0.025 respectively. The structure is built up from SbO₆ octahedra sharing corners or edges and PO₄ tetrahedra sharing corners with octahedra to form a three-dimensional network. The potassium atoms are situated in the interconnected channellike cavities.     

Crystal growth and structure refinement of monoclinic Li2TiO3

Colorless platelet crystals of monoclinic Li₂TiO₃ with a maximum size of 5.0 mm × 5.0 mm × 0.5 mm were successfully grown by a flux method at 1373 K using a LiBO₂-Li₂O system flux. The stoichiometric chemical composition of Li₂TiO₃ was determined by the SEM-EDX, ICP-AES and density measurement using the single crystal samples. The thermal conductivity of the Li₂TiO₃ single crystals was evaluated using hot-disk method. A single-crystal X-ray diffraction study confirmed the monoclinic Li₂SnO₃-type structure, space group C2/c and the lattice parameters of a = 5.0623(5) Å, b = 8.7876(9) Å, c = 9.7533(15) Å, β = 100.212(11)°, and V = 427.01(9) Å³. The crystal structure was refined to the conventional values of R = 2.4% and wR=3.3% for 2187 independent observed reflections. The cationic arrangement of (LiTi₂) layers in Li₂TiO₃ was precisely revealed by the structure analysis.     

Existence de la structure triramsdellite : Li3FeSb2O8

An ordered ramsdellite Li₃FeSb₂O₈, called triramsdellite, was synthesized for the first time. This phase crystallizes in the orthorhombic system, with the possible space groups Pmcn and P2₁ cn and with the parameters $\text{a}\text{= 9.017(4)}\text{A}\text{?}$, $\text{b}\text{= 5.013(2)}\text{A}\text{?}$ and $\text{c}\text{= 9.841(4)}\text{A}\text{?}$. The X-ray powder diffraction study shows that a 1–2 type order appears between the cations belonging to the two sorts of octahedral sites A and B; these sites are preferentially occupied by lithium and antimony respectively according to the formulation |Li₃|_tet|Li_1.5Fe_0.5|^A_oct|FeSb₃|^B_octO₁₂. This structure, which can be described as built up from A₂B₄O₁₂ octahedral units, is compared to the LiSbO₃ and trirutile structures.     

The crystal structure of Li2MoF6

Crystals of Li₂MoF₆ are tetragonal P4₂2₁2 with a_o = 4.6863(7) and c_o = 9.191(2)A, Z = 2 and the calculated density is 3.687 g/cc. The Li⁺ and Mo⁴⁺ ions are octahedrally coordinated. The Li-F distances range from 2.017(2) to 2.102(7)A and the Mo-F distances range from 1.927(2) to 1.945(2)A. The MoF₆^-- ion is coordinated by 10 Li⁺.     

Crystal structure of LuRuB2

Ternary metal borides of the formula MTB₂ have been synthesized in a new structure for M=Sc, Y, Tb, Dy, Ho, Er, Tm, Lu, and T=Ru, Os. Single crystal x-ray diffraction data on LuRuB₂ were refined on an orthorhombic unit cell, space group Pnma, Z=4, and yielded an R factor equal to 0.085. All metal atoms are coplanar with short bond distances of 3.10Å between rare earth atoms which are arranged in zig-zag chains.     

Crystal structure of K4[H2J2O10].8H20

Crystals of K₄ [H₂J₂O₁₀] 8H₂O belong to the triclinic system, space group P 1 with a = 7.161 (2) $\text{A}\text{?}\text{, b}\text{= 10,553}$ (5) $\text{A}\text{?}\text{, c}\text{= 7,081}$ (2) $\text{A}\text{?}\text{, α = 98°1′}$, β = 117°8′, γ = 90°6′ and Z = 1. The crystal structure has been determined on the basis of photographic data from 877 independent reflections, with the final R value of 6,6%. The iodine atoms are surrounded by a distorted octahedra consisting of five oxygen atoms and one OH group. The average J-O distance is 2.03 Å. There are 2 independent K atoms in the structure. K(1) has a coordination number of eight, while K(2) is surrounded by 6 (5 water molecules + one OH group) nearest neighbours.     

Ionic conductivity of Li4GeO4, Li2GeO3 and Li2Ge7O15

The ionic conductivity of polycrystalline samples of three lithium germanates: Li₄GeO₄, Li₂GeO₃, and Li₂Ge₇O₁₅, has been determined using a c techniques and complex plane analysis. Conductivities at 400°C are 8.7 × 10^?5, 1.5 × 10^?5, and $\text{1.4 × 10}{}^{\mathrm{?7}}\text{(Ω·}\text{cm}\text{)}{}^{\mathrm{?1}}$ respectively. The conductivity of Li₄GeO₄ rises appreciably in the range 700–750°C.     

Crystal structure and spectroscopic properties of a new oxyarsenate Li0.5Ni0.25TiOAsO4

The new oxyarsenate Li_0.5Ni_0.25TiOAsO₄ has been synthesized and studied by a combination of X-ray powder diffraction, neutrons powder diffraction and vibrational spectroscopy. Li_0.5Ni_0.25TiOAsO₄ crystallizes in the monoclinic P2₁/c space group with the unit cell parameters: a = 6.5854(3) Å, b = 7.4665(4) Å, c = 7.4969(4) Å, β = 89.884(6)°, V = 368.62(1) Å³ and Z = 4. The structure has been determined at room temperature from neutrons diffraction by the Rietveld method analysis. It is formed by a 3D network of TiO₆ octahedra and AsO₄ tetrahedra sharing corners. Structural refinement shows a partial and a statistical occupancy of 2a and 2b sites by Li⁺ and Ni²⁺ ions. TiO₆ octahedra are linked together by corners and form infinite chains along c-axis. Raman and infrared studies confirm the existence of -TiOTi- chains. Diffuse reflectance spectrum indicates the presence of octahedrally coordinated Ni²⁺ ions.     

Li2ZnTi3O8基微波介质陶瓷的研究进展

Li_2ZnTi_3O_8陶瓷是一种固有烧结温度低的新型微波介质陶瓷,具有较高的品质因数和近零的谐振频率温度系数。主要论述了近年来Li_2ZnTi_3O_8陶瓷制备方法、离子置换改性、氧化物掺杂改性以及低温共烧等方面的研究进展,指出了目前Li_2ZnTi_3O_8陶瓷研究中存在的问题及今后的发展趋势。     

Crystal structure of KHSO4 · KH2PO4

KHSO₄ · KH₂PO₄ is monoclinic $\text{P}\text{2}{}_1\text{n}$ with Z = 2 and the following unit cell dimensions: a = 7.434(3); b = 7.341(3); $\text{c}\text{= 7.148(3)}\text{A}\text{?}$; β = 99.56(5)°.Crystal structure of this salt has been solved, using 1699 independent reflexions with a final R value: 0.034. PO₄ and SO₄ tetrahedra are randomly distributed in the arrangement with a resulting (P.S)-O mean distance of 1.508(3) Å.     

Crystal structure analysis of Y2Cu2O5

Single crystals of Y₂Cu₂O₅ were obtained in the flux growth process by controlled heating of a mixture of Y₂O₃, BaO, and CuO in a molar ratio of 1820. These crystals were analyzed by a single-crystal X-ray diffraction analysis. The crystal contains polymeric chains of Cu₂O₅ interspersed by yttrium ions surrounded by octahedral arrangements of oxygen atoms. Crystal data: space group=Pna2₁,a=10.799(2) Å,b=3.4990(5) Å,c=12.459(2) Å,Z=4, 380 reflections,R=0.026,R _w=0.030.     

Structure et conductivite electrique de verres appartenant au systeme Li2Si2O5 Li2SO4

The conductivity of vitreous electrolytes belonging to the Li₂Si₂O₅ Li₂SO₄ system has been measured over the temperature range 25–300 °C and for Li₂SO₄ concentrations varying from 0–28 mole percent. It has been found that the conductivity increases with the Li₂SO₄ fraction, attaining 10^?5 Ω^?1 cm^?1 at 130°C for the glass containing the highest proportion of sulphate. Raman spectroscopic studies indicate that the tetrahedral SO^2?₄ ions are in the glassy network, inserted or not into the silicate chains.     

Crystal structure of K5NdLi2F10

A single-crystal x-ray diffraction analysis has been performed on K₅NdLi₂F₁₀ synthesized from a melt containing an excess of KF and LiF as a flux. The structure is orthorhombic with space group Pnma, Z = 4, and cell parameters a = 20.65, b = 7.779, $\text{c}\text{= 6.902}\text{A}\text{?}$. A full-matrix least squares refinement gave R = 0.08 for 1056 independent reflections. The basic structural features are sheets, perpendicular to the a-axis, formed by isolated NdF₈ dodecahedra and LiF₄ tetrahedra. The sheets are held together by the K⁺ ions. The compound K₅NdLi₂F₁₀ is the first reported fluoride in which the Nd polyhedra are isolated from each other. The shortest Nd-Nd distance is 6.72 Å, and the concentration of Nd³⁺ ions is 3.60 × 10²¹ cm^?3.     

Des conducteurs ioniques pseudo-bidimensionnels: Li8MO6 (M = Zr,Sn), Li7LO6 (L = Nb,Ta) et Li6In2O6

The ionic conductivity of the pseudo-2D oxides Li₈MO₆ (M = Zr, Sn), Li₇LO₆ (L = Nb, Ta) and Li₆In₂O₆ has been measured and related to their structures. The ideal lattice consists of octahedral sheets [(Li₂M)O₆]_n, [(Li□L)O₆]_n or [(In₂□)O₆]_n of CdI₂-type, between which 6 Li⁺ ions are inserted with a tetrahedral environment. As expected from the structures the highest lithium mobility is observed for Li₇LO₆ phases and the smallest one for Li₈MO₆.     

Low temperature biomimetic synthesis of the Li2ZrO3 nanoparticles containing Li6Zr2O7 and high temperature CO2 capture

Li₂ZrO₃ nanoparticles containing Li₆Zr₂O₇ were prepared by a biomimetic soft solution route and characterized with X-ray diffraction (XRD), transmission electron microscope (TEM) and nitrogen adsorption. The results show that the tetragonal Li₂ZrO₃ nanoparticles containing monoclinic Li₆Zr₂O₇ can be obtained using this simple method. The mean diameter of the nanoparticles is approximately 90 nm and the corresponding specific surface area is 23.7 m² g^− 1. Moreover, the Li₂ZrO₃ nanoparticles obtained were thermally analyzed under a CO₂ flux to evaluate their CO₂ capture capacity at high temperature. It was found that the as-prepared Li₂ZrO₃ nanoparticles would be an effective acceptor for high temperature CO₂ capture.     

Growth and spectroscopic properties of Er-doped Li3Ba2Y3(MoO4)8 crystal

Er³⁺:Li₃Ba₂Y₃(MoO₄)₈ crystal has been grown by the top seeded solution growth method (TSSG) from a flux of Li₂MoO₄ and its morphology was analyzed. The polarized absorption spectra, fluorescence spectra and fluorescence decay curves of the crystal were measured. Based on the Judd-Ofelt (J-O) theory, spectroscopic parameters of Er³⁺:Li₃Ba₂Y₃(MoO₄)₈ crystal, including the oscillator intensity parameters Ω_t (t = 2, 4, 6), spontaneous emission probabilities, fluorescence branching ratios, and radiative lifetimes were calculated and analyzed. Stimulated emission cross-sections of the ⁴I_13/2 → ⁴I_15/2 transition were estimated by the reciprocity method (RM) and the Fuchtbauer-Ladenburg (F-L) formula. Five up-conversion fluorescence bands around 490, 530, 550, 660 and 800 nm were observed with 977 nm excitation, and the possible up-conversion mechanisms were proposed.     

Phase equilibria in the system Li2O-TiO2

The system Li₂O-TiO₂ contains four stable phases: Li₄TiO₄, Li₂TiO₃, Li₄Ti₅O₁₂ and Li₂Ti₃O₇, and one metastable phase, H. Li₂TiO₃ undergoes an order-disorder phase transition at 1215°C. High Li₂TiO₃ forms an extensive range of solid solution between ～44 and 66 mole % TiO₂ and low Li₂TiO₃ forms a more limited range of solid solution between ～47 and 51% TiO₂. The temperature of the order-disorder transition decreases to either side of the Li₂TiO₃ composition. The spinel phase Li₄Ti₅O₁₂, has an upper limit of stability at 1015 ± 5°C, above which it decomposes to high Li₂TiO₃ ss and Li₂Ti₃O₇. Li₂Ti₃O₇ has a lower limit of stability at 957 ± 20°C, below which it decomposes to Li₄Ti₅O₁₂ and rutile. During this decomposition of Li₂Ti₃O₇, phase H, a metastable phase of unknown composition, forms as an intermediate. Li₂Ti₃O₇ forms a short range of solid solutions between ～74 and 76% TiO₂. A phase diagram for the system Li₂O-TiO₂ has been constructed using a combination of results determined here and those reported by GICQUEL, MAYER and BOUAZIZ. X-ray powder diffraction data are given for Li₂Ti₃O₇, Li₄Ti₅O₁₂ and phase H.     

Crystal structure and phase transition of Rb2TeI6

At 293 K crystals of the title compound are tetragonal, space group P4/mnc, with $\text{a}\text{= 8.136(5)}\text{A}\text{?}$, $\text{c}\text{= 11.810(7)}\text{A}\text{?}$ and Z = 2. Octahedral TeI₆^2? anions (distance Te-I: 2.947(2)Å) show a 7.4° rotation around the fourfold axis against the cubic arrangement of the K₂PtCl₆ type structure. Beyond 340 K this cubic structure is found (space group Fm3m with a = 11.67(2) at 370 K).