Title: rotation per helix residue
Long Title: IUPAC Gold Book - rotation per helix residue
DOI: 10.1351/goldbook.14215
Status: current

Definition
Angle of rotation about the chain axis per helix residue.

Note
The value of \(t\) is obtained from the equation \[t = \frac{2\pi N}{M}\] where \(N\) is the number of helix turns in a chain identity period \(c\) and \(M\) is the number of helix residues in \(c\). In cases where the equivalence postulate does not apply, \(t\) is an average value.

Source
- PAC, 2011, 83, 1831. 'Definitions of terms relating to crystalline polymers (IUPAC Recommendations 2011)' on page 1843 (https://doi.org/10.1351/PAC-REC-10-11-13)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/14215/html
- json: https://goldbook.iupac.org/terms/view/14215/json
- xml: https://goldbook.iupac.org/terms/view/14215/xml

Citation: Citation: 'rotation per helix residue' 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.14215
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Accessed: 2026-06-07T01:16:50+00:00