Limits of isomorphous substitution of CnH2n+2 chains in paraffins as a function of temperature

S. K. Filatov, E. N. Kotelnikova, O. A. Golynskaya

Research output

8 Citations (Scopus)

Abstract

Synthetic solid solutions of n-paraffins C23H48and C21h44 have been studied by the thermoroentgenographic method. It is shown that the limits of isomorphous substitutions of molecules in these paraffins with molecular ratios C23: C21 = 1:2, 1:1 and 2:1 are temperature dependent. At rising temperatures all solid solutions first break down to form two phases which coexist in a narrow temperature range (3 –5°C) and then become homogeneous at further elevation of temperature. Isomorphism in the system is established to be violated in the course of intensive structural rearrangements; it gets restored shortly (7 – 9° C) before the orthorhombic-hexagonal polymorphic transformation. A decrease in the limits of isomorphous substitutions which occurs at rising temperatures is explained by differences in energy states of paraffin chains having different lengths: relatively long chains oscillate about their own axes whereas shorter chains perform complete rotations and get “separated” from solid solutions.

Original languageGerman
Pages (from-to)161-167
Number of pages7
JournalZeitschrift fur Kristallographie - New Crystal Structures
Volume188
Issue number3-4
DOIs
Publication statusPublished - 1 Jan 1989

Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

Cite this

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title = "Limits of isomorphous substitution of CnH2n+2 chains in paraffins as a function of temperature",
abstract = "Synthetic solid solutions of n-paraffins C23H48and C21h44 have been studied by the thermoroentgenographic method. It is shown that the limits of isomorphous substitutions of molecules in these paraffins with molecular ratios C23: C21 = 1:2, 1:1 and 2:1 are temperature dependent. At rising temperatures all solid solutions first break down to form two phases which coexist in a narrow temperature range (3 –5°C) and then become homogeneous at further elevation of temperature. Isomorphism in the system is established to be violated in the course of intensive structural rearrangements; it gets restored shortly (7 – 9° C) before the orthorhombic-hexagonal polymorphic transformation. A decrease in the limits of isomorphous substitutions which occurs at rising temperatures is explained by differences in energy states of paraffin chains having different lengths: relatively long chains oscillate about their own axes whereas shorter chains perform complete rotations and get “separated” from solid solutions.",
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T1 - Limits of isomorphous substitution of CnH2n+2 chains in paraffins as a function of temperature

AU - Filatov, S. K.

AU - Kotelnikova, E. N.

AU - Golynskaya, O. A.

PY - 1989/1/1

Y1 - 1989/1/1

N2 - Synthetic solid solutions of n-paraffins C23H48and C21h44 have been studied by the thermoroentgenographic method. It is shown that the limits of isomorphous substitutions of molecules in these paraffins with molecular ratios C23: C21 = 1:2, 1:1 and 2:1 are temperature dependent. At rising temperatures all solid solutions first break down to form two phases which coexist in a narrow temperature range (3 –5°C) and then become homogeneous at further elevation of temperature. Isomorphism in the system is established to be violated in the course of intensive structural rearrangements; it gets restored shortly (7 – 9° C) before the orthorhombic-hexagonal polymorphic transformation. A decrease in the limits of isomorphous substitutions which occurs at rising temperatures is explained by differences in energy states of paraffin chains having different lengths: relatively long chains oscillate about their own axes whereas shorter chains perform complete rotations and get “separated” from solid solutions.

AB - Synthetic solid solutions of n-paraffins C23H48and C21h44 have been studied by the thermoroentgenographic method. It is shown that the limits of isomorphous substitutions of molecules in these paraffins with molecular ratios C23: C21 = 1:2, 1:1 and 2:1 are temperature dependent. At rising temperatures all solid solutions first break down to form two phases which coexist in a narrow temperature range (3 –5°C) and then become homogeneous at further elevation of temperature. Isomorphism in the system is established to be violated in the course of intensive structural rearrangements; it gets restored shortly (7 – 9° C) before the orthorhombic-hexagonal polymorphic transformation. A decrease in the limits of isomorphous substitutions which occurs at rising temperatures is explained by differences in energy states of paraffin chains having different lengths: relatively long chains oscillate about their own axes whereas shorter chains perform complete rotations and get “separated” from solid solutions.

KW - Isomorphous substitution

KW - Paraffins /

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DO - 10.1524/zkri.1989.188.3-4.161

M3 - статья

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JO - Zeitschrift für Kristallographie. New crystal structures

JF - Zeitschrift für Kristallographie. New crystal structures

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