Molecular Geometry of Vanadium Dichloride and Vanadium Trichloride: A Gas-Phase Electron Diffraction and Computational Study (original) (raw)
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The Journal of Chemical Physics, 2014
Six electronic states (X 4 − , A 4 , B 4 , 2 , 2 , 2 + ) of the vanadium monochloride cation (VCl + ) are described using large basis set coupled cluster theory. For the two lowest quartet states (X 4 − and A 4 ), a focal point analysis (FPA) approach was used that conjoined a correlationconsistent family of basis sets up to aug-cc-pwCV5Z-DK with high-order coupled cluster theory through pentuple (CCSDTQP) excitations. FPA adiabatic excitation energies (T 0 ) and spectroscopic constants (r e , r 0 , B e , B 0 ,D e , H e , ω e , v 0 , α e , ω e x e ) were extrapolated to the valence complete basis set Douglas-Kroll (DK) aug-cc-pV∞Z-DK CCSDT level of theory, and additional treatments accounted for higher-order valence electron correlation, core correlation, and spin-orbit coupling. Due to the delicate interplay between dynamical and static electronic correlation, single reference coupled cluster theory is able to provide the correct ground electronic state (X 4 − ), while multireference configuration interaction theory cannot. Perturbations from the first-and second-order spin orbit coupling of low-lying states with quartet spin multiplicity reveal an immensely complex rotational spectrum relative to the isovalent species VO, VS, and TiCl. Computational data on the doublet manifold suggest that the lowest-lying doublet state ( 2 ) has a T e of ∼11 200 cm −1 . Overall, this study shows that laboratory and theoretical rotational spectroscopists must work more closely in tandem to better understand the bonding and structure of molecules containing transition metals.
Electronic states of vanadium(III) in trans-VCl 2(H 2O) 4 + chromophore
Journal of Alloys and Compounds, 2008
The polarized absorption spectra of vanadium(III) in Cs 3 VCl 6 ·4H 2 O complex are presented in the UV-vis region and correspond to the transition from the ground state 3 T 1g ( 3 F) to the excited states 3 T 2g ( 3 F), 3 T 1g ( 3 P) and 3 A 2g ( 3 F). Semiempirical calculations of the crystal-field levels of the vanadium(III) with D 4h point group symmetry in Cs 3 VCl 6 ·4H 2 O chromophore are carried out, leading to a good agreement between the theoretical and experimental energy levels.
Thermochemistry of the Gaseous Vanadium Chlorides VCl, VCl 2 , VCl 3 , and VCl 4
The Journal of Physical Chemistry A, 2008
Gaseous equilibria in the V-Ag-Cl system were studied at elevated temperatures by effusion-beam mass spectrometry, where the pertinent species were generated by reaction of Cl 2 (g) with V + Ag granules in the effusion cell source. Reaction enthalpies were derived from the equilibrium data, and the standard enthalpies of formation at 298 K of gaseous VCl, VCl 2 , and VCl 3 were found to be +49.7,-34.8, and-85.6 kcal mol-1 , respectively. The corresponding bond dissociation energies at 298 K are D(V-Cl)) 102.9 kcal, D(ClV-Cl)) 113.5 kcal, D(Cl 2 V-Cl)) 79.8 kcal, and D(Cl 3 V-Cl)) 69.5 kcal. From these data, the dissociation energy D°0(VCl)) 101.9 kcal mol-1 or 4.42 eV is obtained. An alternate value, ∆ f H°2 98 (VCl 3 ,g))-87.0 kcal mol-1 was derived from third-law analysis of literature sublimation data for VCl 3 (s). In addition, literature thermochemical data on VCl 4 (g) were re-evaluated, leading to ∆ f H°2 98)-126.1 kcal mol-1. The results are compared with various estimates in the literature.
Crystal structure evolution in the van der Waals vanadium trihalides
Journal of Physics: Condensed Matter, 2022
Most transition-metal trihalides are dimorphic. The representative chromium-based triad, CrCl3, CrBr3, CrI3, is characterized by the low-temperature phase adopting the trigonal BiI3-type while the structure of the high-temperature phase is monoclinic of AlCl3 type (C2/m). The structural transition between the two crystallographic phases is of the first-order type with large thermal hysteresis in CrCl3 and CrI3. We studied crystal structures and structural phase transitions of vanadium-based counterparts VCl3, VBr3, and VI3 by measuring specific heat, magnetization, and X-ray diffraction as functions of temperature and observed an inverse situation. In these cases, the high-temperature phase has a higher symmetry while the lowtemperature structure reveals a lower symmetry. The structural phase transition between them shows no measurable hysteresis in contrast to CrX3. Possible relations of the evolution of the ratio c/a of the unit cell parameters, types of crystal structures, and nature of the structural transitions in V and Cr trihalides are discussed.
The crystal structures and properties of [VCL3(THF)2(H2O] and [VCl3(THF)2(H2O)]·THF
Polyhedron, 1996
The structure of the products formed between [mer-VCl3(THF)3] and water in tetrahydrofuran (THF) or dichloromethane were investigated. Two different crystalline species were isolated: [VCl3(THF)2(H2O)] (1) and [VCl3(THF)2(H2O)]·THF (2). Their structures were determined by means of X-ray analysis. In both compounds the vanadium (III) ions are in a distorted octahedral environment surrounded by three mer-chlorine atoms, two trans-situated THF molecules and a water molecule.
Infrared emission spectroscopy and ab initio calculations on VCl
Journal of Molecular Spectroscopy, 2003
The emission spectrum of VCl has been investigated at high resolution in the 3000-19 400 cm À1 region using a Fourier transform spectrometer. The bands were excited in a high temperature carbon tube furnace by the reaction of vanadium metal vapor and a trace of BCl 3 as well as in a microwave discharge lamp by the reaction of VOCl 3 vapor with active nitrogen. The spectra were recorded using the Fourier transform spectrometer associated with the McMath-Pierce telescope of the National Solar Observatory at Kitt Peak. The analysis of the E 5 D-X 5 D system of VCl (previously labeled as ½7:0 5 D-X 5 D) has been extended by analyzing the rotational structure of some additional bands. A rotational analysis of the
Electron Optical Studies of Vanadium Compounds
1988
After an introductory chapter on the theory of electron microscopy, which was the predominant technique used in this study, the work described in this thesis was divided into two parts, namely, the thermal decomposition of ammonium metavanadate and the use of vanadium pentoxide as a support for rhodium catalyst. The thermal decomposition of ammonium metavanadate, up to 400
Rotationally resolved photoelectron spectroscopy of the vanadium dimer
Chemical Physics, 1996
Results of calculations of the rotationally resolved photoelectron spectra of the V: ground state obtained by two-color excitation via the A %I, + X3x, system are reported and compared with recent pulsed-field-ionization zero-kinetic-energy measurements of these spectra. Agreement between the measured and calculated spectra is very encouraging. Both illustrate that the spin-orbit interaction plays an important role in photoionization of the A 'n, state of V2 leading to the X 42, state of V:. Striking differences are seen in the ion rotational distributions for ionization via the A3rIl, and A 3lI2U spin-orbit components.