Cis conformation

{
  "id": "MLC-T-CHM-002088",
  "term": "Cis conformation",
  "field": "Chemistry",
  "definition": "A bond conformation of a polymer main chain in which the torsion angle defined by four consecutive backbone atoms lies within 30 degrees of zero, so the two outer atoms are eclipsed on the same side. It is also called synperiplanar and abbreviated C, and it differs from trans (antiperiplanar, near 180 degrees) and gauche (near 60 degrees). Every backbone bond of the zigzag polyethylene chain is trans, whereas the double bond in cis-1,4-polybutadiene is cis.",
  "subject": "Polymer",
  "see_also": [
    "conformation",
    "deviation",
    "enantiomorph",
    "gauche",
    "torsion angle",
    "cis, trans"
  ],
  "references": [
    "Purple Book, 1st ed., p. 41 (http://old.iupac.org/publications/books/author/metanomski.html)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/cis-conformation/"
}