Compound Type
Unknown
Last updated
A deliberate placeholder for a compound whose molecular type we have not established from a source we are willing to cite. It is a recorded state rather than an empty field: it means we looked and could not confirm, not that nobody has got round to the record. Every compound must carry exactly one type, so this value exists to avoid guessing at one.
Why it matters here
This is the type-level version of the site's not on file convention, the same choice that leaves every empty field explicitly marked rather than blank, and it lets you tell an unverified record from a confidently classified one.
What it is not
Unknown does not mean novel, exotic or unstudied; it usually means the supplier documentation was ambiguous or the name maps to more than one substance. It is also not the same as the Unknown value in the molecular origin domain, which records that the biological source is unestablished while the molecular type may be perfectly clear.
Also called
- unknown
- unclassified
- tbd
Unclassified and TBD turn up in imported data and resolve here. All three record the same state.
Compounds carrying this term
None on file yet. This term is in the controlled vocabulary but no compound record currently uses it — which is a statement about our coverage, not about the term.