Synthesis and crystal structural study of ternary molybdate NaMg3In(MoO4)5

We have synthesized single crystals of a temary molybdate NaMg₃In(MoO₄)₅ and cam'ed out an X-ray structural study (a KM-4 automatic difiactometer, MoK, radiation, 4503 F, R = 0.047). The triclinic unit cell dimensions are a = 7.0476(7), b = 17.935(2), c = 6.9849(7)Å, = 87.650(9), = 100.980(8), = 92.510(9)°, V= 865.5(2) A³, Z = 2, and space group P^–1. The crystal structure involves MoO₄ tetrahedra and (Mg, In)0₆ octahedra forming a three-dimensional framework with Na atoms located in its cavities. The compound melts at 990°C with decomposition.Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Institute of Physics, Siberian Branch, Russian Academy of Sciences. Buryatian Institute of Natural Sciences, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 147–151, September–October, 1993.Translated by T. Yudanova     

Chromium ion incorporation in the crystal structure of BGO

Comprehensive investigations have been performed by EPR and optical spectroscopy for Bi₃GeO₄ crystals doped with chromium ions. It is demonstrated that the known optical absorption spectrum for chromium ions, specifically, the triplet in the region 600–900 nm has an analog in the EPR spectra — the center with electron spin S = 1. The spectrum is described by the spin-Hamiltonian with the parameters D = 550 G, E = 10 G, g _xx = g _yy = 1.915, g _zz = 1.932. The EPR spectrum is dictated by Cr⁴⁺ incorporation at the germanium sites. Luminescence observed in the region 1.2–1.7 μm is also caused by transitions of Cr⁴⁺ with tetrahedral surroundings to germanium sites. Original Russian Text Copyright ? 2005 N. V. Chernei, V. A. Nadolinnyi, N. V. Ivannikova, V. A. Gusev, I. N. Kupriyanov, V. N. Shlegel, and Ya. V. Vasiliev __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 3, pp. 444–450, May–June, 2005.     

Crystal and molecular structure of nitraminotetrazole and nitramino-1,2,4-triazole. IV. 5-nitraminotetrazole sodium salt sesquihydrate

The structure of 5-nitraminotetrazole sodium salt sesquihydrate was determined by X-ray diffraction. The crystals are monoclinic, space group P2₁/c;a = 3.551(1) Å, b = 21.834(4) Å, c = 9.075(2) Å; = 110.68(3)°; V = 658.3(2) ų; Z = 4; _calc = 1.807 g/cm³. The anion is planar and has an intramolecular hydrogen bond. The negative charge of the anion is localized on one of the oxygens of the nitro group. The sodium cation (c.n.6) is coordinated by three oxygen atoms of different anions and three oxygens of crystallization water. One of the crystallization water molecules is disordered in the unit cell. The anions are hydrogen-bonded with each other and with crystallization water molecules.Original Russian Text Copyright © 2004 by A. M. Astakhov, A. D. Vasiliev, M. S. Molokeev, L. A. Kruglyakova, A. M. Sirotinin, and R. S. StepanovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 562–565, May–June 2004.     

Crystal and molecular structure of copper(II) <Emphasis Type="Italic">trans</Emphasis>-bis-(2-(methylimino)-4-pentanonate)

Synthesis and X-ray diffraction study of trans-bis-(2-(methylimino)-4-pentanonato)Cu(II), which is methyl-substituted ketoiminate, is reported. Crystal data for CuN₂O₂C₁₂H₂₀: a = 7.374(1) , b = 9.171(1) , c = 10.823(2) ; = 96.51(1)°, = 106.12(1)°, = 96.81(1)°, space group P , Z = 2, d _calc = 1.38 g/cm³, d _exp = 1.37 g/cm³, R = 0.037. The structure is molecular and consists of isolated trans-complexes. The coordination polyhedron of the copper atom is intermediate between the square and tetrahedron; the average distances are Cu-O 1.91 and Cu-N 1.95 , the O-Cu-O and N-Cu-N trans bond angles are 145.5° and 150.3°, respectively. The O-Cu-N chelate angle is 94.6°. The calculated energies of van der Waals intermolecular interactions are compared with the thermogravimetric characteristics of the complex with ketoiminate and copper(II) ethylenediamine-bis-acetylacetonate.Original Russian Text Copyright © 2004 by I. A. Baidina, P. A Stabnikov, A. D. Vasiliev, S. A. Gromilov, and I. K. IgumenovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 706–712, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Plutonium(III) oxidation under α-irradiation in nitric acid solutions

Plutonium(III) oxidation under high energy α-irradiation in nitric acid solutions has been studied relative to concentrations of both nitric acid (0.12–2.9 mol/l) and plutonium (1.4–10 mmol/l) using spectrophotometric techniques. Curium-244 has been used as the basic alpha-irradiation source. It has been stated that in solutions with nitric acid concentrations lower than 0.5 mol/l plutonium(III) does not oxidize completely. In the course of the process the formation of a plutonium(IV) peroxide complex is observed. Increase in the nitric acid concentration results in that in both the rate and degree of plutonium(III) oxidation. When c_{HNO 3} is higher than 0.5 mol/l the peroxide complex does not form and the process assumes an autocatalytic character. It has also been shown that plutonium(III) oxidation kinetics is significantly affected by nitrous acid, one of the nitrate ion radiolysis products. To describe plutonium chemical transformations under irradiation in nitric acid solutions, a kinetic scheme is proposed. The calculations have been carried out on a BESM-6 computer; a satisfactory agreement between the calculated and experimental data has been obtained.     

The Navruz experiment: Cooperative monitoring for radionuclides and metals in Central Asia transboundary rivers

Summary This paper presents the results of radioecological investigation of Central Asian rivers.<Emphasis Type=Bold><Emphasis Type=Italic> </Emphasis></Emphasis>This work was done as part of the Navruz Project, a cooperative, transboundary river monitoring project involving rivers and institutions in Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan, and facilitated by Sandia National Laboratories in the United States. The study of waterborne radionuclides and metals concentrations in Central Asia is of particular interest because of the history of nuclear materials mining, fabrication, transport, and storage there, when it was part of the Soviet Union. This development left a legacy of radionuclides and metals contamination in some Central Asian regions, which poses a clear health hazard to populations who rely heavily upon surface water for agricultural irrigation and direct domestic consumption.     

Hybrid organic–inorganic light emitting diodes

Specific features of plane-geometry nanocrystals (CdSe nanoplatelets) functioning in an organic–inorganic light emitting diode are analyzed.