High temperature infrared spectra of dimeric and monomeric AlBr3, AlI3 and GaCl3 in the vapour phase

Sjøgren, Carl E.; Klæboe, P.; Rytter, Erling

doi:10.1016/0584-8539(84)80078-1

Cited by 55 publications

(17 citation statements)

References 19 publications

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“…However, the values of n 9 (154 cm À1 for Ga 2 Cl 6 , and 118.5 cm À1 for Fe 2 Cl 6 ) give rise to some concern. In 1967, n 9 for Ga 2 Cl 6 was calculated 14 to be 215 cm À1 and in 1984, 13 168 cm À1 (to agree with the experimental results at the time of 202 cm À1 and 154 cm À1 , respectively). This illustrates the difficulty of assigning infrared active bands in such a complicated molecule, with 18 modes of vibration of which eight are infrared-active.…”

Section: Summarises Thesupporting

confidence: 57%

The observation of the electronic spectrum of Fe2Cl6 in the gas phase

Hodges

Beattie

Brown

2006

Phys. Chem. Chem. Phys.

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Section: Summarises Thesupporting

confidence: 57%

The observation of the electronic spectrum of Fe2Cl6 in the gas phase

Hodges

Beattie

Brown

2006

Phys. Chem. Chem. Phys.

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“…The molecular structures and vibrational behavior of the aluminum halide monomers and dimers, AlX 3 and Al 2 X 6 , have been extensively studied by various experimental methods (Raman − and IR ,− spectroscopy, gas-phase electron diffraction (GED − ) and by ab initio molecular orbital calculations. − These studies confirm that the dimers in the gas phase have structures consistent with D 2 h symmetry that may be pictured as two AlX 4 tetrahedra sharing a common edge (Figure ). Also, there is little doubt that the monomers are planar with D 3 h symmetry, although a pyramidal structure for the molecules (later shown to be unlikely ,, ) has been proposed on the basis of an interpretation of infrared data …”

Section: Introductionmentioning

confidence: 95%

Molecular Structure of the Aluminum Halides, Al₂Cl₆, AlCl₃, Al₂Br₆, AlBr₃, and AlI₃, Obtained by Gas-Phase Electron-Diffraction and ab Initio Molecular Orbital Calculations

et al. 1999

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Gas-phase electron-diffraction (GED) data together with results from ab initio molecular orbital and normal coordinate calculations have been used to determine the structures of the aluminum trihalides AlX3 (X = Cl, Br, I) and the chloride and bromide dimers Al2Cl6 and Al2Br6. No monomeric species were detected in the vapors of Al2Cl6 at the experimental temperature of 150 °C, nor in Al2Br6 at167 °C, but the vapors of AlCl3 at 400 °C and AlBr3 at 330 °C contained respectively 29 (3)% and 7 (4)% dimer and the AlI3 at 300 °C about 8% I2. The known equilibrium symmetry of the dimers is D 2 h , but the molecules have a very low-frequency, large-amplitude, ring-puckering mode that lowers the thermal average symmetry to C 2 v . The effect of this large-amplitude mode on the interatomic distances was handled by dynamic models of the structures which consisted of a set of pseudoconformers spaced at even intervals along the ring-puckering angle 2Φ. The ring-puckering potential was assumed to be V(Φ) = V 4 0Φ4 + V 2 0Φ2, and the individual pseudoconformers were given Boltzmann weights. The structures were defined in terms of the geometrically consistent r α space constraining the differences between corresponding bond distances and bond angles in the different pseudoconformers to values obtained from ab initio calculations at the HF/6-311G(d) level. Results for the principal distances (r g/Å), angles (∠α,θ/deg), and potential constants (V i 0/kcal mol deg-1) from the combined GED/ab initio study for Al2Cl6/Al2Br6 with estimated 2σ uncertainties are Al−Xb = 2.250(3)/2.433(7), Al−Xt = 2.061(2)/2.234(4), XbAlXb = 90.0(8)/91.6(6), XtAlXt = 122.1(31)/122.1(31), 〈θ〉 = 180 − 2Φ = 165.5(59)/158.2(91), V 4 0 = 0.0/75.0 (assumed), V 2 0 = 25.0/0.0 (assumed). The potential constants could not be refined; although the single-term values listed provide good fits, in each case combinations of quadratic and quartic terms also worked well. For the monomers AlCl3, AlBr3, and AlI3 (D 3 h symmetry assumed in r α space) the distances (r g/Å) with estimated 2σ uncertainties are Al−Cl = 2.062(3), Al−Br = 2.221(3), and Al−I = 2.459(5) Å. Vibrational force fields were evaluated for all molecules. The experimental, theoretical, and vibrational results are discussed.

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“…However, later studies described the aluminum triiodide crystals to be molecular, consisting of Al 2 I 6 units [14]. On the other hand, there have been numerous spectroscopic studies of aluminum halides, including matrix isolation infrared (IR) spectroscopic study [15,16] and an IR and Raman spectroscopic study of the melt [17] and gas-phase [18][19][20]. Although ab initio molecular orbital [21,22] calculations have been performed for AlX 3 and Al 2 X 6 (X = Cl and Br), little has been studied for these molecules by high-level computational techniques [23,24].…”

Section: Introductionmentioning

confidence: 99%

Theoretical studies on vibrational spectra of some aluminum halides: Effect of theoretical methods and basis sets

Zhang

Jiang

2010

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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High temperature infrared spectra of dimeric and monomeric AlBr3, AlI3 and GaCl3 in the vapour phase

Cited by 55 publications

References 19 publications

The observation of the electronic spectrum of Fe2Cl6 in the gas phase

The observation of the electronic spectrum of Fe2Cl6 in the gas phase

Molecular Structure of the Aluminum Halides, Al₂Cl₆, AlCl₃, Al₂Br₆, AlBr₃, and AlI₃, Obtained by Gas-Phase Electron-Diffraction and ab Initio Molecular Orbital Calculations

Theoretical studies on vibrational spectra of some aluminum halides: Effect of theoretical methods and basis sets

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High temperature infrared spectra of dimeric and monomeric AlBr3, AlI3 and GaCl3 in the vapour phase

Cited by 55 publications

References 19 publications

The observation of the electronic spectrum of Fe2Cl6 in the gas phase

The observation of the electronic spectrum of Fe2Cl6 in the gas phase

Molecular Structure of the Aluminum Halides, Al2Cl6, AlCl3, Al2Br6, AlBr3, and AlI3, Obtained by Gas-Phase Electron-Diffraction and ab Initio Molecular Orbital Calculations

Theoretical studies on vibrational spectra of some aluminum halides: Effect of theoretical methods and basis sets

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Molecular Structure of the Aluminum Halides, Al₂Cl₆, AlCl₃, Al₂Br₆, AlBr₃, and AlI₃, Obtained by Gas-Phase Electron-Diffraction and ab Initio Molecular Orbital Calculations