Substance classification guide
CAS documents 19 substance classes. The table below preserves their published names and shows where this initial PubCAS release provides a browsing group.
PubCAS group membership is derived from ChEBI identity and ontology information. It is not an official CAS REGISTRY class assignment.
| CAS class name | PubCAS coverage |
|---|---|
| Alloy | Not represented in this release |
| Coordination Compound | 21 records → |
| Element | 60 records → |
| General Derivative | Not represented in this release |
| Generic Registration | Not represented in this release |
| Incompletely Defined Substance | Not represented in this release |
| Manual Registration | Not represented in this release |
| Mineral | 22 records → |
| Mixture | Not represented in this release |
| Nucleic Acid Sequence | Not represented in this release |
| Organic/Inorganic Small Molecule | 784 records → |
| Polymer | Not represented in this release |
| Protein/Peptide Sequence | 3 records → |
| Radical Ion | Not represented in this release |
| Registered Concept | Not represented in this release |
| Ring Parent | Not represented in this release |
| Salt and Compound With | 110 records → |
| Subatomic Particle | Not represented in this release |
| Tabular Inorganic | Not represented in this release |
Read CAS’s official substance class definitions ↗
Other ways to browse
Chemical-family pages use ChEBI ontology ancestry. Element pages use the elements appearing in the reported formula. Alphabetical pages use the preferred display name. These methods describe different aspects of a substance and may overlap.
How grouping is derived
Element records are identified from a one-element formula and source charge. Other groups use ChEBI peptide, mineral, coordination, salt and hydrate relationships, together with explicit components in the formula. Remaining defined molecular records appear in the small-molecule browsing group. This navigation rule does not reproduce CAS’s internal registration decisions.