Vibrational Spectra of Single Crystals. Polymorphic Solids of Cyclohexane

Obremski, Robert J.; Brown, Chris W.; Lippincott, Ellis R.

doi:10.1063/1.1669807

Cited by 57 publications

(18 citation statements)

References 9 publications

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“…Infrared and Raman spectroscopy are at least in agreement in suggesting a centrosymmetric molecular site (Zhizhin & Sterin, 1965;Ito, 1965;Sechkarev & Brutan, 1965;Le Roy, 1965;Obremski et al, 1968;Brown et al, 1970); the only exception is the work by Dows (1965). X-ray results have been obtained from powder patterns (Lonsdale & Smith, 1939;Krishna Murti, 1958;Leibler & Przedmojski, 1962;Renaud & Fourme, 1966a).…”

Section: Phase Isupporting

confidence: 51%

“…Infrared and Raman spectroscopy indicate a centrosymmetric molecular site (Carpenter & Halford, 1947;Zhizhin & Sterin, 1965;Ito, 1965;Obremski, Brown & Lippincott, 1968;Brown, Obremski & Lippincott, 1970). X-ray results were first obtained from powder patterns (Hassel & Kringstad, 1930;Hassel & Sommerfeldt, 1938) which were interpreted on the basis of a primitive cubic cell; more recently, single-crystal photographs gave a face-centred cubic cell (Oda, 1948;Renaud & Fourme, 1966a).…”

Section: Phase Imentioning

confidence: 99%

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Crystal structure of cyclohexane I and II

Kahn¹,

Fourme²,

André³

et al. 1973

Acta Crystallogr Sect B

178

108

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Cyclohexane C6H12 (m.p. 279.8 °K) undergoes an isothermal transition at 186 °K. The so-called phase I is stable between 279.8 and 186°K, phase II below 186°K. Starting from a single crystal I grown by a zone melting technique at 187 °K, suitable single crystals II were obtained through a careful control of the phase transformation and annealing at 185 °K for two days. X-ray diffraction data have been collected at 195 and 115 °K by the low-temperature precession technique. At 115 °K, crystal data are: monoclinic cell, a= 11.23 (2), b = 6.44 (2), c= 8.20 (2) A, fl= 108.83 (17) °, Z= 4; space group Cc or C2/c (the analysis confirmed the centrosymmetric group). The crystal and molecular structures were refined to an R index of 0.061 ; the 'chair'-shaped molecule departs slightly but significantly from Dan symmetry. The rigid-body model is a good approximation for the thermal motion. At 195 °K, crystal data for the plastic phase I are: cubic cell, a = 8.61 (2)/~, Z= 4, space group Fm3m. Using the molecular shape previously found, two types of orientational disorder have been investigated: isotropic reorientations of the molecules about their centre of gravity (Pauling-Fowler model) and step reorientations between 24 equivalent positions (Frenkel model). In this case, the packing was found by a Monte-Carlo method coupled with a rigidgroup least-squares refinement. The Frenkel model gives a better agreement with experiment. A tentative interpretation of the transformation is given. The same general procedure can probably be applied to other plastic crystals.

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Section: Phase Isupporting

confidence: 51%

Section: Phase Imentioning

confidence: 99%

Crystal structure of cyclohexane I and II

Kahn¹,

Fourme²,

André³

et al. 1973

Acta Crystallogr Sect B

178

108

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“…From liquid to phase I, cyclohexane solidifies as the pressure increases. At 0.5 GPa there occurs I to III transition which follows III to IV at 1.3 GPa, as observed experimentally using Xray diffraction [9], infrared spectroscopy [3][4][5][6][7][8], Raman spectroscopy [11][12][13]. Below 186.1 K, an orientationally ordered structure, namely, phase II, occurs [11].…”

Section: Introductionmentioning

confidence: 73%

“…Using different experimental techniques, its thermodynamics [1], dynamic [2][3][4][5][6][7][8], and structural [9][10][11] properties have been investigated.…”

Section: Introductionmentioning

confidence: 99%

Application of the Pippard Relations to Cyclohexane near the Melting Point

Yurtseven

2012

ISRN Thermodynamics

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“…In particular, spectroscopic studies such as Raman [3,6,7,20], infrared [3,15,20], X-ray diraction [8,16] and neutron powder diraction [5] have also been reported in the literature to investigate the phase transitions in cyclohexane.…”

Section: Introductionmentioning

confidence: 99%

Pressure Dependence of the Raman Modes Related to the Phase Transitions in Cyclohexane

Yurtseven

Cebeci

2015

Acta Phys. Pol. A

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The pressure dependence of the Raman frequencies for the ν21 mode is studied by using the volume data at room temperature close to the transitions among the phases of III, IV and V in cyclohexane. By determining the pressure dependence of the mode Grüneisen parameter γT in the phases and taking the average values, the Raman frequencies of those modes associated with the phase transitions are predicted through the volume data in cyclohexane. Our predicted Raman frequencies agree with those observed experimentally in this organic molecule. The Raman frequencies of the other modes can be calculated in cyclohexane and also in some molecular crystals using the method given here.

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Vibrational Spectra of Single Crystals. Polymorphic Solids of Cyclohexane

Cited by 57 publications

References 9 publications

Crystal structure of cyclohexane I and II

Crystal structure of cyclohexane I and II

Application of the Pippard Relations to Cyclohexane near the Melting Point

Pressure Dependence of the Raman Modes Related to the Phase Transitions in Cyclohexane

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