Subgroup-supergroup transition

{
  "id": "MLC-T-CHM-011515",
  "term": "Subgroup-supergroup transition",
  "field": "Chemistry",
  "definition": "A type of structural phase transition where the symmetry of the lower-temperature phase (subgroup) is a subgroup of the higher-temperature phase (supergroup). This relationship implies a loss of symmetry elements upon cooling or an increase in symmetry upon heating. These transitions are often continuous or nearly continuous, exhibiting a second-order or weakly first-order character.",
  "synonyms": [
    "symmetry-breaking transition"
  ],
  "subject": "Inorganic Chemistry",
  "references": [
    "PAC, 1994, 66, 577. 'Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)' on page 591 (https://doi.org/10.1351/pac199466030577)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/subgroup-supergroup-transition/"
}