The polarized Raman and i.r. spectra of KHF2

The Formation of Percolative Composites with a High Dielectric Constant and High Conductivity

“…Therefore, we chose this sample for investigating in detail the spectroscopic differences with pure PVDF samples before and after thermal treatment. As shown in Figure 4 b, after thermal treatment, three peaks belonging to KHF 2 appeared at around 2040 cm −1 , 1440 cm −1 , and 1230 cm −1 , which supports the hypothesis of formation of KHF 2 18. Furthermore, a new peak also appeared in the samples after thermal treatment, which will be discussed later.…”

Neutron Compton scattering as a molecular characterization technique: A study onNaHF2

“…However, for quite a long time, some important aspects of this ion kept their elusive character, such as the supposed centrosymmetric position of the H atom, the exact value of the bond energy, and the extent and nature ͑i.e., whether mechanical or electrical͒ of the anharmonicities in the ͓F-H-F͔ − internal vibrations. 38 Nowadays, also with the help of ab initio and semiempirical calculations, the large amount of experimental and simulated data has been largely reconciled, obtaining a general consensus on a purely centrosymmetric ionic structure with a H-F distance d HF ranging between d HF = 1.132 Å and d HF = 1.138 Å and a bond energy of about E b = 163± 4 kJ/ mole in the gas phase. 39 On the contrary, as far as the study of the ionic vibrations is concerned, no exhaustive and comprehensive representation has been reached, even though some relevant works on Raman, 38,40 IR, 38,40,41 and neutron 40,42,43 spectroscopies have to be mentioned.…”

“…38 Nowadays, also with the help of ab initio and semiempirical calculations, the large amount of experimental and simulated data has been largely reconciled, obtaining a general consensus on a purely centrosymmetric ionic structure with a H-F distance d HF ranging between d HF = 1.132 Å and d HF = 1.138 Å and a bond energy of about E b = 163± 4 kJ/ mole in the gas phase. 39 On the contrary, as far as the study of the ionic vibrations is concerned, no exhaustive and comprehensive representation has been reached, even though some relevant works on Raman, 38,40 IR, 38,40,41 and neutron 40,42,43 spectroscopies have to be mentioned. Especially the last, 43 a high-resolution inelastic neutron scattering measurement on polycrystalline NaHF 2 pointed out beyond any doubt the existence of a large LO/TO splitting of 2 ͑bending͒ but also revealed conspicuous anharmonicity in overtones and combinations.…”

Hydrogen bonding. 8. Preparation, properties, and low-temperature infrared structural analysis of ammonium and alkylammonium trihydrogen tetrafluorides and tetramethylammonium dihydrogen trifluoride

“…Newman and Badger47 first assigned the bands in the 1800-5000-cm"1 region of the low-temperature spectrum of potassium hydrogen difluoride to the progression v3 + nv\, where v3 is the antisymmetric F-H-F stretch at 1425 cm'1 and v{ the symmetric F-F stretch at 600 cm"1. This assignment has been recently confirmed by a detailed single-crystal polarized infrared and Raman study by Wilkinson et al 28 Hadzi et al33 have also assigned a weak band at 2350 cm"1 in potassium dihydrogen trifluoride to an unspecified combination. The combination bands of the alkylammonium complex acid fluorides and the summations that we assign to them are listed in Tables II and III.…”