- Carbon only
- Carbon and Oxygen
- Carbon and Nitrogen
- Carbon, Nitrogen, and Oxygen
- Carbon and other
- Carbon, Oxygen, and other(s)
- Carbon, Nitrogen, and other(s)
- Carbon, Nitrogen, Oxygen, and other(s)
- Organometallic, C-M or O-M-O
- Inorganic (no monovalent non-metals bonded to C)
- Unclassified Chemicals