Low-Temperature Solid State Synthesis and Characterization of Superconducting Vanadium Nitride

Superconducting vanadium nitride （VN） is successfully synthesized by a solid-state reaction of vanadium pentox- ide, sodium amide and sulfur in an autoclave at a relatively low temperature （240-400℃）. The obtained samples are characterized by x-ray diffraction, x-ray photoelectron spectroscopy and transmission electron microscopy. The result of the magnetization of the obtained VN product as a function of temperature indicates that the onset superconducting transition temperature is about 8.4K. Furthermore, the possible reaction mechanism is also discussed.

Solid-state synthesis of Sr-and Co-doped LaMnO_3 perovskites

The synthesis process for La 1- x Sr x Mn 1- y Co y O 3- δ ( x = 0.2, 0.3; y = 0.2, 0.8, designated as LSMC below) perovskite oxides prepared by solid state reaction was investigated using DSC/TG, XRD, EPMA and particle size analysis methods. It was found that LSMCs were all of single phase and the synthesis process might be divided into three stages: the decomposition of reactants, the formation of LaMn(Co)O 3 based oxides, and the formation of LSMC solid solution. Typical average and the peak value of particle size, and the specific surface area are 14.65?μm, 16.4?μm and 1.38?m 2/mL, respectively, for mixed reactants and are 23.81?μm, 32.11?μm and 0.5?m 2/mL, respectively, for powder synthesized at 1?200?℃ for 8?h in air.

STUDIES ON SOLID STATE REACTIONS OF COORDINATION COMPOUNDS(LXⅡ)Solid state synthesis and crystal structure of the complex ICu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)CIJ·0.5CS_2

[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15cm^(-1),F(000)=1855,R=0.052, R_W=0.045 for 3930 observed reflections with Ⅰ>1.5σ(Ⅰ).The central metal atom has a dis. torted tetrahedral geometry with bond lengths Cu-S=2.384(2) (Au-S=2.389(4)), Cu-Cl=2.481(3)(Au-Cl=2.474(1))and Cu-P=2.269(2)-2.289(2)(Au-P=2.270(4)-2.279(4)) .

Solid State Synthesis and Crystal Structure of K_3SI

A new ternary alkali metal chalcogenide halide, K3SI, has been synthesized by solid state reaction method and structurally characterized by X-ray crystallography. The crystal belongs to hexagonal, space group P63cm with a = 11.699（I ）, c = 5.8279（9） A°, Mr = 276.26, V = 690.8（1 ）A°^ 3, Z = 6, D, = 3.985 g/cm^3, F（000） = 756, μ = 9.913 mm^-1, S = 1.004, R = 0.0719 and wR = 0.2204. The title compound is the first example containing S anion in the ternary alkali metal chalcogenide halides family M3QX （M = alkali metal, Q = chalcogenide, X - halide）, which crystallizes in the hexagonal anti-perovskite structure type.

Dynamic recrystallization behavior and mechanical properties of bimodal scale Al2O3 reinforced AZ31 composites by soild state synthesis

In this paper,(500 nm 1%+5μm 3%)bimodal scale Al2O3p/AZ31 composites was fabricated by solid state synthesis and the effect of bimodal scale Al2O3 particulates on its dynamic recrystallization behavior and mechanical properties was investigated.The optical microscopy,scanning electron microscopy,transmission electron microscopy and electron universal strength tester composites were used to characterize the composites.The results indicate that the grains size of the composites are significantly refined and the mechanical properties are obviously improved.Due to the presence of the bimodal scale Al2o3 particulates,the high-density dislocation zone is formed around nano-Al2o3p and the particle deformation zone is formed near micron-ABOap.These zones are ideal sites for the formation of recrystallization nucleus.Meanwhile,the addition of the bimodal scale Al2o3 particulates may delay or hinder the growth of matrix grain through the pining effect on the grain boundaries,resulting in significantly improving the yield strength and tensile strength of Al2O3p/AZ31 composites.

Synthesis of Novel Quaternary Selenide K_2CdSnSe_4

A novel quaternary metal selenide, K2CdSnSe4, was synthesized via a molten-salt reaction at 550 ℃. The compound has a one-dimensional structure containing a chain of ∞^1[CdSnSe4]^2- anions separated by K^＋ cations. The crystal belongs to the space group I-4^-2m, with the unit cell parameters a=0.80298（11） nm, b=0.80298（11） nm, c=0.69217（14） nm, α=β=γ=90°. A reflectance spectroscopy study reveals the nature of the semiconductor with an energy gap of 1.7 eV for the compound and it has a strong optical absorotion in a range of 2--5 eV.

Synthesis and Crystal Structure of Er_2Si_2O_7

The title compound crystallizes in monoclinic system, space group C2/m with cell dimensions of a=6. 843(2), b=8. 939(2), c=4. 720(1) A, β=101. 77(2), V=282. 7A3, Z=2, Mr=502. 69, Dc=5' 91 g·cm-3, u(MoKa)=303. 0cm-1, F(000) ~ 440. The structure solution and refinement are based on 869 uniqueobserved reflections with I≥3(I) and the final discrepancy factors converged at R=0. 034, Rw= 0. 042. The structure is considered to be the oxygen atoms packed innearly hexagonal arrangement with rare earth atoms in the octahedral and silicon atomsin tetrahedral holes in alternately parallel layers.

Solid state synthesis and structure of two novel polyoxometalates [(n-Bu)_4N]_4[M_6o_(19)][Ag_21_4](M=Mo,W)

The reaction of [NH4]2[MO2S2],AgI and (n-Bu)4NBr in solid state produced the polyoxometalates [(n-Bu)4N]4[M6O19][Ag2l4] (1,M=Mo;2,M=W) which were structurally determined.The crystals of 1 and 2 are isomorphous,monoclinic,space group P221/c.1,a=1.6624(2),6=1.6699(3),c=1.7217(2) nm,(8=98.29(1)°,V =4.729(1) nm3,Z=2,R=0.040,Rw=0.037;2,a= 1.6636(3),6=1.6733(3),c=1.7190(3) nm,β=98.25(1)°,V=4.736(1) nm3,Z=2,R=0.038,Rw=0.047.The results of the structure determination showed that the two compounds had the same structures whose skeletons are composed of [Ag2I4]2-and [M6O19]2-The difference of them and heteropolymetalate compounds synthesized in solution is that the title compounds contain cluster ion,heteropolymetalate and organic cations,while the latter is only composed of heteropolymetalate and organic cations.

Molten Salt Synthesis, Crystal Structure and Optical Properties of a Novel Quaternary Metal Selenide, K_2AgIn_3Se_6

K2AgIn3Se6 was synthesized by a molten-salt (alkali-metal polyselenide flux) reaction at 500 ℃. The orange red granular crystal crystallizes in monoclinic space group C2/c with cell parameters, a=1.16411(7) nm, b=1.16348(8) nm, c=2.14179(12) nm, V=2.8740(9) nm3, and Z=8. The crystal has a new two-dimensional structure containing 2∞[AgIn3Se6]2- anionic layers separated by K+ cations and the 2∞[AgIn3Se6]2- layer is constructed with corner-shared [AgSe4] and [InSe4] tetrahedra. The optical band gap of K2AgIn3Se6 was determined to be ca. 2.9 eV by UV/vis/NIR diffuse reflectance spectra.

Structure and spectral measurements of a new rubidium europium polyphosphate

A new rubidium europium polyphosphate, RbEu(PO3)4, was synthesized by the high-temperature solution reaction and studied by single-crystal X-ray diffraction (XRD) technique. RbEu(PO3)4 belongs to the monoclinic space group P21/n (Z=4) and characterizes a three-dimensional framework made up from double PO4 spiral chains, RbO11, and EuO8 polyhedra. The absorption spectrum indicates that the compound has no absorption above 320nm with insulator characteristic. In addition, the infrared spectroscopy was carried out.