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SO Stretching Vibrations

The molecular mass determined osmometrically corresponds to the formula S5O. The SO stretching vibration was observed in the infrared spectrum at 1119 cm (at -65 °G) indicating an exocyclic sulfoxide group similar to the one in SsO (see below). At -50 °G the solution of S5O may be kept for several days without decomposition which usually results in a Tyndall effect caused by a colloidal polymeric sulfuroxide which is the expected decomposition product. At 25 °G some decomposition already occurs within... [Pg.213]

The SO stretching vibration gives rise to a very strong infrared absorption at 1112 cm (in CHBr3), and Raman lines of medium intensity have been observed at 1092 cm for a-SsO and at 1102 cm for PS O. The SS stretch-... [Pg.214]

On exposure to air, the initially clear orange crystals of the adduct turn cloudy within 1 min as a result of the loss of CS2, and ultimately form a yellow oil. In CS2 solution the adduct decomposes fairly rapidly at room temperature the decomposition products SOCI2, SO2, Sg, and SbCls are already detectable after 10 min. The SO stretching vibrations of Si202-2SbCl5 occur at 940 cm in the infrared spectrum (in CS2) [61]. Free S12O2 has not been prepared yet. [Pg.216]

The SO stretching vibration of S7O was observed at 1134 cm in the IR spectrum of a CS2 solution and at 1089/1102/1113 cm in the Raman spectrum of a soHd sample at -90 °C (the three very weak Raman lines probably originate from the intermolecular S—0 interactions). The two strongest Raman lines at 292 and 325 cm have been assigned to the SS stretching vibrations of the particularly weak bonds (see the bond distances in Fig. 2). [Pg.217]

The infrared and Raman spectra of SgO [78] reflect the molecular structure. The SO stretching vibration gives rise to very strong IR absorptions at 1133 cm (CS2 solution) and at 1104 cm (CsCl disc) but to a weak Raman line at 1080 cm (all at 25 C). Since SgO is a strong oxidant, KBr discs should not be used (formation of sulfur bromides). The Raman hnes in the... [Pg.220]

Degradation of PBI-PS was studied by elemental analysis and FT-IR spectroscopy. It was foimd that the intensities of SO stretching vibrations decreased after heating the PBI-PS samples above 400 °C for 1 h. These results are similar to those reported by Giesehnan and Reynolds [166] who found that the degradation of PBI-PS occurs due to desulfonation. Hence, alkylsulfonated PBI is more thermally stable than sulfonated aromatic polymer electrolytes characterised by a degradation temperature between... [Pg.113]

K takes more energy to stretch a bond than to bend it, so stretching vibrations are found at higher wavenumbers than bending vibrations. [Pg.617]

B2.5.351 after multiphoton excitation via the CF stretching vibration at 1070 cm. More than 17 photons are needed to break the C-I bond, a typical value in IR laser chemistry. Contributions from direct absorption (i) are insignificant, so that the process almost exclusively follows the quasi-resonant mechanism (iii), which can be treated by generalized first-order kinetics. As an example, figure B2.5.15 illustrates the fonnation of I atoms (upper trace) during excitation with the pulse sequence of a mode-coupled CO2 laser (lower trace). In addition to the mtensity, /, the fluence, F, of radiation is a very important parameter in IR laser chemistry (and more generally in nuiltiphoton excitation) ... [Pg.2131]

Explicit forms of the coefficients Tt and A depend on the coordinate system employed, the level of approximation applied, and so on. They can be chosen, for example, such that a part of the coupling with other degrees of freedom (typically stretching vibrations) is accounted for. In the space-fixed coordinate system at the infinitesimal bending vibrations, Tt + 7 reduces to the kinetic energy operator of a two-dimensional (2D) isotropic haiinonic oscillator. [Pg.480]

In an atomic level simulation, the bond stretch vibrations are usually the fastest motions in the molecular dynamics of biomolecules, so the evolution of the stretch vibration is taken as the reference propagator with the smallest time step. The nonbonded interactions, including van der Waals and electrostatic forces, are the slowest varying interactions, and a much larger time-step may be used. The bending, torsion and hydrogen-bonding forces are treated as intermediate time-scale interactions. [Pg.309]

When the above analysis is applied to a diatomic species such as HCl, only k = 0 is present since the only vibration present in such a molecule is the bond stretching vibration, which has a symmetry. Moreover, the rotational functions are spherical harmonics (which can be viewed as D l, m, K (Q,< >,X) functions with K = 0), so the K and K quantum numbers are identically zero. As a result, the product of 3-j symbols... [Pg.407]

In the absence of X-ray crystallographic data vibrational spectroscopy can. sometimes provide information concerning the mode of ligation, the position of the two n(SO) stretching modes in particular often providing a useful but not always reliable diagnostic " ... [Pg.702]

Now consider a molecular stretching vibration that alternately elongates and compresses axial (parallel to z, let s say) and equatorial bonds as outlined in Fig. 7-3. Imagine an extreme vibration of this kind that eventually distorts an octahedral molecule so as to gradually remove two trans ligands (again, let this direction be... [Pg.131]


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Stretching vibration

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