Inelastic Neutron Scattering Study of Phonon Density of States of Iodine Oxides and First-Principles Calculations
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Engineering topics
Publications and source records attributed to Christe, Karl O..
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The purely chemical synthesis of fluorine is a spectacular reaction which for more than a century had been believed to be impossible. In 1986, it was finally experimentally achieved, but since then this important reaction has not been further studied and its detailed mechanism had been a mystery. The known thermal stability of MnF 4 casts serious doubts on the originally proposed hypothesis that MnF 4 is thermodynamically unstable and decomposes spontaneously to a lower manganese fluoride and F 2 . This apparent discrepancy has now been resolved experimentally and by electronic structure calculations. It is shown that the reductive elimination of F 2 requires a large excess of SbF 5 and occurs in the last reaction step when in the intermediate [SbF 6 ][MnF 2 ][Sb 2 F 11 ] the addition of one more SbF 5 molecule to the [SbF 6 ] - anion generates a second tridentate [Sb 2 F 11 ] - anion. The two tridentate [Sb 2 F 11 ] - anions then provide six fluorine bridges to the Mn atom thereby facilitating the reductive elimination of the two fluorine ligands as F 2 .
Abstract The crystal structures of [NH 3 F] + [CF 3 SO 3 ] − , [NH 2 F 2 ] + [SbF 6 ] − , and [N 2 F 3 ] + [Sb 3 F 16 ] − have been determined, representing the first structural characterizations of these simple fluoro‐nitrogen cations. The influences of the hybridization of the central nitrogen atom and of the number of fluorine substituents on the N−F bond lengths are evaluated for the series N 2 F + , N 2 F 3 + , NF 2 O + , NH 3 F + , NH 2 F 2 + , and NF 4 + . It is shown that the N−F bond length decreases from 1.40 Å to 1.26 Å with increasing fluorine substitution and increasing s‐character of the nitrogen atom, and that unusual N−F bond lengths reported in the previous literature are caused by disorder problems
The crystal structures of [NH 3 F] + [CF 3 SO 3 ] – , [NH 2 F 2 ] + [SbF 6 ] – , and [N 2 F 3 ] + [Sb 3 F 16 ] – have been determined, representing the first structural characterizations of these simple fluoro-nitrogen cations. The influences of the hybridization of the central nitrogen atom and of the number of fluorine substituents on the N–F bond lengths are evaluated for the series N 2 F + , N 2 F 3 + , NF 2 O + , NH 3 F + , NH 2 F 2 + , and NF 4 + . Here it is shown that the N–F bond length decreases from 1.40 Å to 1.26 Å with increasing fluorine substitution and increasing s-character of the nitrogen atom, and that unusual N–F bond lengths reported in the previous literature are caused by disorder problems.