Chemical substance

{
  "id": "MLC-T-CHM-001968",
  "term": "Chemical substance",
  "field": "Chemistry",
  "definition": "A kind of matter whose composition is constant and which is specified by the molecules, formula units, or atoms that make it up, such as a pure element or compound. A mixture of several substances is a separate category and is not itself a chemical substance. Its identity is shown by physical properties such as melting point, density, and refractive index.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "melting",
    "refractive index"
  ],
  "references": [
    "PAC, 2021, 93, 997. 'Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)' on page 1004 (https://doi.org/10.1515/pac-2019-0819)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/chemical-substance/"
}