Structural studies of cyclohexane IV

Abstract

We report an extensive neutron powder diffraction study of the high-pressure phase IV of cyclohexanediE. Using constrained Rietveld refinement we deduce approximate atomic positions for this phase which are found to be in close accord with the predictions of energy-minimization calculations. The likely relationship between the unit cell of phase IV and that of the ambient-pressure phase II is also presented. We further demonstrate, by means of an X-ray powder diffraction study of cyclohexane-hl2, that phase IV can be produced in a metastable state at ambient pressure by rapid quenching to 77 K from the liquid. This finding contradicts a previous report [Burns & Dacol (1984). Solid State Commun. 51,[773][774][775] claiming that the ambient-pressure metastable phase is an orientational glass.

Vibrational spectroscopy and DFT calculations of N,N′‐dicyclohexylcarbodiimide

“…The calculated C-C bond distances in the cyclohexyl rings are in the range 1.5311-1.5329 Å, which compare favourably with experimental values for cyclohexane (1.5194-1.5275 [19] and 1.5296-1.5403 Å [20] ) and cylohexylamine hydrochloride (1.4931-1.5222 Å [21] ). The computed C-N distance (1.4660 Å) is also comparable with that determined for cylohexylamine hydrochloride (1.4873 Å [21] ).…”

Application of the Pippard Relations to Cyclohexane near the Melting Point

“…It has been reported that phase V retains structural similarities with the monoclinic phase IV [16], as also pointed out previously [12].…”

High pressure Raman spectroscopic study of structural polymorphismin cyclohexane

“…Prior static high pressure studies of cyclohexane [1][2][3][4][5] were performed at pressures below 3 GPa; dynamic shock wave studies were performed up to 40 GPa. The R 1 and R 2 lines of a ruby in the cyclohexane sample were well-resolved to our highest pressure, and the sample was highly transparent.…”