Li(VO2)3(TeO3)2

The title compound, lithium tris[dioxidovanadium(V)] bis[trioxidotellurium(IV)], contains chains of edge‐sharing distorted VO₆ octahedra. The pyramidal TeO₃ groups crosslink the chains into sheets. Finally, an Li⁺ cation adopting an unusual capped trigonal–bipyramidal LiO₆ geometry bridges the layers to complete a three‐dimensional structure.     

(CF3)2PAsH2 und (CF3)2AsAsH2

(CF₃)₂PAsH₂ and (CF₃)₂AsAsH₂ (CF₃)₂PAsH₂ is obtained in yields between 30 and 60% according to eq. (1) (CF₃)₂AsAsH₂ is formed by the analogous reaction with (CF₃)₂AsI, but is not sufficiently stable to be isolated. Both compounds are decomposed according to eq. (2) (CF₃)₂PAsH₂ can be studied in solution below ?40°C; it is characterized by molar mass determination and by its n.m.r. spectra (¹H, ¹⁹F, ³¹P). Reactions with polar [HBr, (CH₃)₂AsH, (CH₃)₂PN(CH₃)₂] and nonpolar [Br₂, As₂(CH₃)₄] reagents proceed by cleavage of the P? As bond.     

Dimethylarsenazid (CH3)2AsN3, Dimethylwismutazid (CH3)2BiN3 und Dimethylthalliumzid (CH3)2TiN3

The reaction of (CH₃)₂AsJ and AgN₃ yields (CH₃)₂AsN₃; a colourless liquid (b. p. 136°C) which dissolves as a monomeric in benzene. (CH₃)₂BiN₃ is precipitated in form of colourless needles (dec. temp. 150°C) from an etherical solution of Bi(CH₃)₃ and HN₃. According to its vibrational and mass spectra the molecules are not associated although the (CH₃)₂BiN₃ is not soluble; dipole association of this polar molecules is assumed for the crystal structure. (CH₃)₂TlN₃ can be obtained from TI(CH₃)₃ and ClN₃ as well as from (CH₃)₂TlOH and HN₃ in form of colourless needles and leaves (dec. temp. 245°C). According to its vibrational spectra it has an ionic structure, (CH₃? Tl? CH₃)⁺N^?₃.     

Spectroscopic properties of Er(3+)/Yb(3+) co-doped Bi(2)O(3)-B(2)O(3)-GeO(2) glasses

Er(3+)/Yb(3+) co-doped 60Bi(2)O(3)-(40 - x)B(2)O(3)-xGeO(2) (BBG; x=0, 5, 10, 15 mol%) glasses that are suitable for fiber lasers, amplifiers have been fabricated and characterized. The absorption spectra, emission spectra, and lifetime of the (4)I(13/2) level and quantum efficiency of Er(3+):(4)I(13/2) --> (4)I(15/2) transition were measured and calculated. With the substitution of GeO(2) for B(2)O(3), both Delta lambda(eff) and sigma(e) decrease from 75 to 71 nm and 9.88 to 8.12 x 10(-21) cm(2), respectively. The measured lifetime of the (4)I(13/2) level and quantum efficiency of Er(3+):(4)I(13/2) --> (4)I(15/2) transition increase from 1.18 to 1.5 ms and 36.2% to 43.2%, respectively. The emission spectra of Er(3+):(4)I(13/2) --> (4)I(15/2) transition was also analyzed using a peak-fit routine, and an equivalent four-level system was proposed to estimate the stark splitting for the (4)I(15/2) and (4)I(13/2) levels of Er(3+) in the BBG glasses. The results indicate that the (4)I(13/2) --> (4)I(15/2) emission of Er(3+) can be exhibit a considerable broadening due to a significant enhance the peak A, and D emission.     

Perfluoralkyltellur-Verbindungen: Oxidation von (CF3)2Te Darstellungen und Eigenschaften von (CF3)2TeCl2, (CF3)2TeBr2, (CF3)2Te(ONO2)2 und (CF3)2TeO [1]

Perfluorosalkyl Tellurium Compounds: Oxidation of (CF₃)₂Te; Preparations and Properties of (CF₃)₂TeCl₂, (CF₃)₂TeBr₂, (CF₃)₂Te(ONO₂)₂, and (CF₃)₂TeO From the oxidation of (CF₃)₂Te with Cl₂, Br₂, O₂, and ClONO₂ the new trifluoromethyl tellurium compounds (CF₃)₂TeCl₂, (CF₃)₂TeBr₂, (CF₃)₂TeO, and (CF₃)₂Te(ONO₂)₂ are prepared. The ¹⁹F, ¹³C and ¹²⁵Te n.m.r. spectra, the vibrational and mass spectra as well as the chemical properties of these compounds are described. By variation of the reaction conditions CF₃TeCl₃ and CF₃TeBr₃ are also formed. It has not been possible to isolate (CF₃)₂TeI₂, but there is some evidence that it is formed as an intermediate. (CF₃)₂Te reacts with ozone to a very unstable compound, which decomposes at low temperature.     

LiMn3(SeO3)2(HSeO3)6

The title compound, lithium trimanganese bis­[trioxo­selenate(IV)] hexa­kis[hydrogentrioxoselenate(IV)], is built up from a vertex‐sharing network of distorted Mn^IIIO₆ octa­hedra, SeO₃ and HSeO₃ pyramids and unusual Li(OH)₆ octa­hedra, resulting in a dense three‐dimensional structure. Mn, Li and one Se atom have site symmetries of , , and 3, respectively. An O—H⋯O hydrogen bond helps to establish the crystal packing.     

Die IR-Spektren von [Cr(O2)2(NH3)3] und K3[Cr(O2)2(CN)3]

The infrared spectra of the title compounds are reported and discussed. The influence of the peroxide groups on the bond properties of the other ligands and some characteristics of the metal—peroxide interactions are analyzed.     

RbLi2Ga2(BO3)3

The structure of rubidium dilithium digallium tris­(borate), RbLi₂Ga₂(BO₃)₃, contains two‐dimensional sheets of open‐branched rings of GaO₄ tetrahedra and planar BO₃ triangles that are joined by LiO₄ tetrahedra to form a three‐dimensional framework. Ten‐coordinate Rb atoms lie on twofold axes and occupy channels within the framework that extend along the b axis.     

Spectroscopic properties of Dy(3+) ions in NaF-B(2)O(3)-Al(2)O(3) glasses

This paper reports the optical properties of Dy(3+) in sodium fluoroborate glasses of the type XNaF.(89-X)B(2)O(3).10 Al(2)O(3).1Dy(2)O(3) (where X=8, 12, 16, 20 and 24). Judd-Ofelt intensity parameters (Omega(2), Omega(4), Omega(6)) are derived from the absorption spectra. The Judd-Ofelt theory has been applied to interpret the local environment of Dy(3+) ions and bond covalency of RE-O bond. These parameters have been used to calculate radiative transition probabilities (A(rad)), lifetimes (tau(R)) and branching ratios (beta(R)) for the excited level (4)F(9/2). The predicted values of tau(R) are compared with the measured values for (4)F(9/2) level for five glass compositions (Glass (A-E)). The stimulated emission cross-section sigma(lambda(P)) are also evaluated for the (4)F(9/2)-->(6)H(J) (J=11/2, 13/2, and 15/2) transitions.     

Heat capacity and thermodynamic properties of tellurites Yb2(TeO3)3, Dy2(TeO3)3 and Er2(TeO3)3

The experimental results obtained for the specific molar heat capacity of the tellurites Yb₂(TeO₃)₃, Dy₂(TeO₃)₃ and Er₂(TeO₃)₃ are processed by the least squares method. The temperature dependence of the specific molar heat capacity derived is used to determine the thermodynamic properties: entropy ( \Updelta_T￠^T S_m⁰ ), \left( {\Updelta_{T\prime }^{T} S_{m}^{0} } \right), enthalpy ( \Updelta_T￠^T H_m⁰ ) \left( {\Updelta_{T\prime }^{T} H_{m}^{0} } \right) and Gibbs function ( \Updelta_T￠^T G_m⁰ ) \left( {\Updelta_{T\prime }^{T} G_{m}^{0} } \right) of the tellurites Yb₂(TeO₃)₃, Dy₂(TeO₃)₃ and Er₂(TeO₃)₃.     

Thermal transformations of complexes Co2(μ-OOCBut)4(NEt3)2 and Co3(μ-OOCBut)2(μ-OOCBut)4(NEt3)2

The features of thermal transformations of trimethylacetatocobalt complexes Co₂(μ-OOCBu^t)₄(NEt₃)₂ and Co₃(μ-OOCBu^t)₂(μ-OOCBu^t)₄(NEt₃)₂ with attendant geometric alterations are considered as dependent on temperature on the basis of single-crystal X-ray diffraction, magnetochemical, and thermochemical investigations.     

Bildung und struktur der Cyclophosphane P4(CMe3)2[P(CMe3)2]2 und P4(SiMe3)2[P(CMe3)2]2

Formation and Structure of the Cyclophosphanes P₄(CMe₃)₂[P(CMe₃)₂]₂ and P₄(SiMe₃)₂[P(CMe₃)₂]₂ n-Triphosphanes showing a SiMe₃ and a Cl substituent at the atoms P¹ and P², like (Me₃C)₂P? P(SiMe₃)? P(CMe₃)Cl 3 or (Me₃C)₂P? P(Cl)? P(SiMe₃)₂ 4 are stable only at temperatures below ?30°C. Above this temperature these compounds lose Me₃SiCl, thus forming cyclotetraphosphanes, P₄(CMe₃)₂[P(CMe₃)₂]₂ 1 out of 3 , P₄(SiMe₃)₂[P(SiMe₃)₂]₂ 2a (cis) and 2b (trans) out of 4 . The formation of 1 proceeds via (Me₃C)₂P? P?PCMe₃ 5 as intermediate compound, which after addition to cyclopentadiene to give the Diels-Alder-adduct 6 (exo and endo isomers) was isolated. 6 generates 5 , which then forms the dimer compound 1 . Likewise (Me₃C)₂P? P?P-SiMe₃ 8 (as proven by the adduct 7 ) is formed out of 4 , leading to 2a (cis) and 2b (trans). Compound 1 is also formed out of the iso-tetraphosphane P[P(CMe₃)₂]₂[P(CMe₃)Cl] 9 , which loses P(CMe₃)₂Cl when warmed to a temperature of 20°C. 1 crystallizes monoclinically in the space group P2₁/a (no. 14); a = 1762.0(15) pm; b = 1687.2(18) pm; c = 1170.5(9) pm; β = 109.18(5)° and Z = 4 formula units in the elementary cell. The molecule possesses E conformation. The central four-membered ring is puckered (approx. symmetry 4 2m; dihedral angle 47.4°), thus bringing the substituents into a quasi equatorial position and the nonbonding electron pairs into a quasi axial position. The bond lengths in the four-membered ring of 1 (d (P? P) = 222.9 pm) are only slightly longer than the exocyclic bonds (221.8 pm). The endocyclic bond angles \documentclass{article}\pagestyle{empty}\begin{document}$ \bar \beta $\end{document}(P/P/P) are 85.0°, the torsion angles are ±33° and d (P? C) = 189.7 pm.     

Crystal structure of Li2Cu3(SeO3)2(SeO4)2

Summary Single crystal X-ray data of the hydrothermally grown new phase Li₂Cu₃(SeO₃)₂(SeO₄)₂ were measured with a four-circle diffractometer up to sin /=0.81 Å^–1 [I2/a,Z=4,V=1175.5 ų,a=16.293(6),b=5.007(2),c=14.448(6) Å, = 94.21(1)°]. The structure was determined by direct and Fourier methods and refined toR=0.034,R _w =0.027 for 2 086 independent reflections.Cu(1)^[4+1]O₅ forms a tetragonal pyramid, Cu(2)^{[4 + 2]}O₆ is a strongly elongated octahedron. The Li atom is surrounded by four O atoms forming a distorted tetrahedron. Se(IV)O₃ and Se(VI)O₄ groups are in accordance to literature, mean Se-O bond lengths are 1.714 and 1.644 Å.

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Die Kristallstruktur von Li₂Cu₃(SeO₃)₂(SeO₄)₂

Zusammenfassung Einkristall-Röntgendaten der hydrothermal gezüchteten neuen Phase Li₂Cu₃(SeO₃)₂(SeO₄)₂ wurden mit einem Vierkreisdiffraktometer im Bereich bis zu sin /=0.81 Å^–1 gemessen [I2/a,Z=4,V=1175.5 ų,a=16.293(6),b=5.007(2),c=14.448(6) Å, =94.21(1)°]. Die Kristallstruktur wurde mittels direkter und Fourier-Methoden bestimmt und für 2 086 unabhängige Reflexe zuR=0.034,R _w =0.027 verfeinert.Cu(1)^[4+1]O₅ bildet eine tetragonale Pyramide, Cu(2)^[4+2]O₆ ist ein stark verlängertes Oktaeder. Das Li-Atom ist von vier O-Atomen in Gestalt eines verzerrten Tetraeders umgeben. Die Se(IV)O₃-und Se(VI)O₄-Gruppen entsprechen der Literatur, die mittleren Se-O-Abstände betragen 1.714 und 1.644 Å.

     

Interpretation der Schwingungsspektren von (CH3)2SO2, (CH3)2SO(NH) und (CH3)2S(NH)2 unter Verwendung eines Kopplungsstufenverfahrens

Normal Coordinate Analysis of (CH₃)₂SO₂, (CH₃)₂SO(NH), and (CH₃)₂S(NH)₂ using the Method of Stepwise Coupling The qualitative assignment of the vibrational spectra of (CH₃)₂SO₂ ( 1 ), (CH₃)₂SO(NH) ( 2 a ), and (CH₃)₂S(NH)₂ ( 3 a ) and of the C and N deuterated derivatives of 2 a and 3 a is used in a normal coordinate analysis by the method of stepwise coupling. The force constants and the energy distributions are calculated in symmetry coordinates using a generalized valence force field.