13470-20-7Relevant articles and documents
A spatially separated [KBr6]5- anion in the cyanido-bridged uranium(IV) compound [U2(CN)3(NH3)14]5+[KBr6]5-·NH3
Deubner, H. Lars,Kraus, Florian
, p. 111 - 116 (2020)
The reaction of uranium tetrabromide with potassium cyanide in anhydrous liquid ammonia at room temperature leads to the formation of brown crystals of [U2(CN)3(NH3)14]5+ [KBr6]5- · NH3. We determined the crystal structure of the compound by single crystal X-ray diffraction. To the best of our knowledge it contains the unprecedented spatially separated [KBr6]5- anion and presents the first uranium(IV) cyanide compound which forms a layer structure. The compound crystallizes in the trigonal space group P3 m1 (No. 164) with a = 10.3246(13), c = 8.4255(17) ?, V = 777.8(3) ?3, Z = 1 at T = 100 K and is well described with the Niggli formula 2 ∞[U(CN)3/2(NH3)7/1]2[KBr6/1].
Absorption spectrum and crystal-field analysis of U4+ ions in CsCdBr3 single crystals
Karbowiak,Mech,Drozdzyński
, p. 135 - 145 (2005)
Single crystals of U4+:CsCdBr3 were grown by the Bridgman-Stockbarger technique. It has been assumed, that U4+ ions are substituting two Cd2+ ions and possess the C3v site symmetry. Thirty seven energy levels, located between 4000 and 25,000 cm -1 and encompassing all but the 1S0 multiplet, were assigned from 7 K absorption spectra. The symmetry of the levels were determined on the basis of the observed small splitting of the Γ3 doublets as well as by a comparison of low temperature absorption spectra of the U4+:CsCdBr3 with that previously reported for U4+ in Cs2UBr6 and Cs 2ZrBr6 single crystals. A crystal-field analysis was performed by fitting eight atomic (in the orthogonal formalism) and 6 crystal-field parameters to the experimental Stark levels with an r.m.s. deviation of 100 cm-1. The obtained values of the Hamiltonian parameters are discussed and compared with those reported in previous analyses of U4+ ions. The relatively strong crystal field, resulting in N v = 8530 cm-1 proves that in the CsCdBr3 crystals the U4+ ions are located at a high symmetry site.
Study of the electronic structure of the actinide tetrabromides ThBr4 and UBr4 using ultraviolet photoelectron spectroscopy and density functional calculations
Beeching,Dyke,Morris,Ogden
, p. 9832 - 9839 (2001)
Ultraviolet photoelectron spectroscopy and density functional theory was used to study the electronic structure of actinide tetrabromides. A high temperature photoelectron spectrometer was used to record photoelectron spectra for ThBr4 and UBr4. Vertical ionization energies were calculated for the tetrahalides and supporting matrix isolation experiments were carried out.
Facile Syntheses of pure Uranium(III) Halides: UF3, UCl3, UBr3, and UI3
Rudel, Stefan S.,Deubner, H. Lars,Scheibe, Benjamin,Conrad, Matthias,Kraus, Florian
, p. 323 - 329 (2018/04/05)
Herein we describe a convenient lab scale synthesis for pure and solvent-free binary uranium(III) halides UCl3, UBr3, and UI3. This is achieved by the reduction of the respective uranium(IV) halides with elemental silicon in borosilicate ampoules at moderate temperature. The silicon tetrahalides SiX4 formed as a side product are utilized for the removal of excess starting material via a chemical vapor transport reaction. The syntheses introduced herein avoid the need for pure metallic uranium and are based on uranium(IV) halides synthesized from UO2 and the respective aluminum halides and purified by chemical vapor transport. These uranium(III) halides are obtained in single crystalline form. A similar reaction yields UF3 as a microcrystalline powder. However, no beneficial transport reaction occurs with this halide. Also, a higher temperature has to be applied and steel ampoules have to be used. The identities and purity of the products were checked by powder X-ray diffraction as well as IR spectroscopy. The synthesis of UI3 enabled its crystal structure determination on single crystals for the first time. UI3 crystallizes in the PuBr3 structure type with space group type Cmcm and a = 4.3208(9), b = 13.923(3), c = 9.923(2) ?, V = 596.9(2) ?3, and Z = 4 at T = 100 K.
Facile syntheses of pure uranium halides: UCl4, UBr4 and UI4
Rudel, Stefan S.,Kraus, Florian
, p. 5835 - 5842 (2017/07/10)
Herein we describe convenient lab scale syntheses of several uranium(iv) halides of high purity by reaction of AlX3 (X = Cl, Br and I) with UO2, which is readily available by reduction of uranyl salts like UO2(NO3/su
The structure of the uranium tetrabromide molecule
Ezhov, Yu. S.,Bazhanov, V. I.,Komarov, S. A.,Popik, M. S.,Sevast'yanov, V. G.,Yuldashev, F.
, p. 1698 - 1699 (2007/10/02)
The structure of the UBr4 molecule has been investigated by gas electron diffraction.It was found to have C2ν symmetry with the following parameters (Texp = 900 K): R(UBr) = 2.68(1) Angstroem and β(Br'UBr) = 100(1) deg.The frequencie
