Metallic fuel for Na-cooled reactors with an extended burnup cycle

Bencheikh, A.; Karam, R.A.

doi:10.1016/0306-4549(85)90090-8

Cited by 5 publications

(4 citation statements)

References 5 publications

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“…The 2054-cm -1 band, which has the largest absorptivity of all the components, was assigned to “free” SCN - . Another study of SCN - in methanol by Bencheikh showed that only four bands are necessary to simulate the ν CN spectral envelope (2090, 2071, 2055, and 2037 cm -1 ) , Their results are consistent with hydrogen bonding of the solvent to the nitrogen end of the thiocyanate anion.…”

Section: Introductionmentioning

confidence: 69%

Solvation of SCN^- and SeCN^- Anions in Hydrogen-Bonding Solvents

1996

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The primary solvation sphere surrounding the thiocyanate or the selenocyanide anion in protic solvents, such as methanol, N-methylformamide and formamide, forms intimate hydrogen bonds with these anions. These interactions perturb the electron density and vibrational modes of these anions and can therefore be studied by NMR and infrared spectroscopies. In neat solutions, these solvents form hydrogen bonds to the nitrogen end along the molecular axis and nonaxially to the π cloud of the C−N bond, although a substantial proportion of the anions is not hydrogen bonded. In nitromethane solutions, the thiocyanate and selenocyanide anions form weak complexes with methanol and the amide solvents (K < 1 M-1), which is an order of magnitude smaller than that of OCN- with the same solvents, determined in our previous investigation of the cyanate anion. The remarkable differences in the solvation of these singly charged anions can be understood by theoretical calculations of their electrostatic potentials.

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Section: Introductionmentioning

confidence: 69%

Solvation of SCN^- and SeCN^- Anions in Hydrogen-Bonding Solvents

1996

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“…For example, the frequency of the ν CN vibration in the Na + (12C4) 2 SCN - crystal is substantially lower (2045 cm -1 ) than its value of 2065 cm -1 in the gas phase . In high dielectric solvents, this value drops to ∼2059 cm -1 ; in low dielectric solvents, the value for the ν CN vibration of SCN - can be as low as 2045 cm -1 . − The frequency of this vibrational mode has been related to the dielectric constant of the solvent by the Onsager model of the dielectric continuum. − Thus, although in the crystals studied in this work the thiocyanate anion is ∼6 Å from any sodium cation, the vibrational modes may be affected by the positive charges of the surrounding cations.…”

Section: Discussionmentioning

confidence: 99%

“…The solvation of the thiocyanate anion has been studied by a number of authors. − Infrared spectroscopy has been an important experimental technique to identify likely solvent complexes in solution. − Most of the vibrational assignments for these solvates have been derived from interionic complexes. − Generally, ionic bonding by alkali metals to the nitrogen atom of SCN - increases the frequencies of both the ν CN and ν CS stretching modes with respect to their values in the unperturbed anion. An ionic interaction to the sulfur atom increases the frequency of the ν CN mode and decreases the frequency of the ν CS mode .…”

Section: Introductionmentioning

confidence: 99%

“…The presence of two nonaxial electrostatic interactions to the nitrogen atom, as exemplified by the (LiNCS) 2 dimer, reduces the frequency of the ν CN vibration and increases the frequency of the ν CS vibration . The structures of numerous SCN - complexes and the thermodynamics of their formation have been studied by considering characteristic vibrations of these complexes. − Positive ν CN frequency shifts for SCN - ·HOMe have been attributed to hydrogen bonding along the molecular axis of the anion and red-shifted frequencies have been assigned to nonaxial interactions at the C−N bond of the anion. − , Our group has also attributed a red-shifted ν CN frequency to a single nonaxial interaction to the nitrogen atom of SCN - …”

Section: Introductionmentioning

confidence: 99%

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Nonaxial Hydrogen Bond in the Na⁺(12-Crown-4)₂SCN·HOMe Complex

et al. 1996

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The structures for Na+(12-crown-4)2SCN- and Na+(12-crown-4)2SCN-·HOMe have been determined by X-ray crystallography. In the crystalline solvate, the methanol molecule forms a nonaxial hydrogen bond to the nitrogen atom of thiocyanate anion. This uncommon hydrogen bonded structure markedly affects the frequency of the νCN vibration, which is lowered with respect to the unperturbed anion in Na+(12-crown-4)2SCN-. Theoretical studies of SCN-·HOMe complexes also predict that nonaxial hydrogen bonds lower the frequency of the νCN vibration, but potential energy calculations do not reveal the preferred angle for a nonlinear interaction.

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