Title: ideal crystalline chain conformation
Long Title: IUPAC Gold Book - ideal crystalline chain conformation
DOI: 10.1351/goldbook.14210
Status: current

Definition
Minimum energy conformation of an isolated polymer chain constructed according to the equivalence postulate and approximating the conformation found in a crystalline phase.

Notes
1) If the symmetry elements present in the crystal do not correspond with those that characterize the ideal crystalline chain conformation, the chain conformation may be distorted in the crystal.
2) Symmetry elements characterizing the ideal crystalline chain conformation may be noncrystallographic (see rod group), i.e., they may not apply to the packing in certain crystal polymorphs. For example, the ideal crystalline chain conformation of isotactic polypropylene is \(3_{1}\) helix but, while the \(\ce{\upbeta\mbox{-}phase}\) crystal structure allows for the helical \(3_{1}\) symmetry operator, the \(\ce{\upalpha\mbox{-}}\) or the \(\ce{\upgamma\mbox{-}phase}\) of this polymer do not.

Related Terms
- crystal polymorphs: https://goldbook.iupac.org//terms/view/14219
- rod group: https://goldbook.iupac.org//terms/view/14214

Source
- PAC, 2011, 83, 1831. 'Definitions of terms relating to crystalline polymers (IUPAC Recommendations 2011)' on page 1841 (https://doi.org/10.1351/PAC-REC-10-11-13)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/14210/html
- json: https://goldbook.iupac.org/terms/view/14210/json
- xml: https://goldbook.iupac.org/terms/view/14210/xml

Citation: Citation: 'ideal crystalline chain conformation' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.14210
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Accessed: 2026-05-08T23:29:37+00:00