Chemical documentation is full of terms that look self-explanatory and are not. An LD50 without a species is not a fact. An index number is not a CAS number. A substance missing from an inventory has not been cleared. These pages explain the vocabulary that regulatory documents are written in, so that a sheet can be read rather than trusted.
Every page here answers one question completely, cites the regulation it rests on, and says plainly where a term stops being informative. Nothing here is a substitute for the legal texts, and nothing here is advice about your specific material.
Identity
- CAS Registry Numbers, and the check digit
- What the number identifies, why the last digit can be verified by hand, and the four things a CAS number deliberately does not tell you.
- EC numbers, InChI, SMILES and the other chemical identifiers
- Which identifier to quote for which purpose, why an InChIKey can be compared by eye, and what identifier coverage tells you about a record.
Classification
- CLP Annex VI: harmonised classification and the index number
- The difference between a supplier’s own classification and one decided at Union level, what an index number is, and why an absent entry is not a clean bill of health.
- Hazard and precautionary statements: H-codes and P-codes
- How the codes are structured, why combined P-statements must be reproduced whole, and why the official wording is not yours to translate freshly.
Regulation
- What REACH is, and who is responsible for the safety data sheet
- Registration, evaluation, authorisation and restriction as four separate mechanisms — and why there is no tonnage threshold for the safety data sheet itself.
- SVHC and the REACH candidate list
- Why candidate-list inclusion is neither a ban nor a formality, the Article 33 duty that reaches manufacturers of finished goods, and the 0.1 % threshold.
Data
- LD50, LC50 and EC50: what the numbers mean
- What has to travel with a toxicity value for it to be usable, how the values feed classification, and the four questions they cannot answer.
- OEL, DNEL and PNEC: three kinds of exposure limit
- One is law, one is the registrant’s calculation, one is about ecosystems. Why compliance with a DNEL is not compliance with an exposure limit.
- Flash point, autoignition and explosive limits
- Why a flash point without its test method is not a specification, how it drives classification, and why section 9 and section 14 are allowed to disagree.
Documents
- The sixteen sections of a safety data sheet
- What belongs in each section under REACH Annex II, why the order is fixed, and what a correct format does not guarantee.
- What a safety data sheet is
- The purpose of the document, who is responsible for it under REACH, and what it does and does not do for the person holding it.
- How MolGod documentation is built
- The datasets behind a document, the order of assembly, what is checked, and what is deliberately not checked.
Why this section exists
MolGod sells documentation, and a document its reader cannot evaluate is worth less than one they can. These pages exist so that a buyer can check our work — and anyone else’s. They are free, they carry no sales argument, and they are useful whether or not you ever buy anything here.
If a term you need is missing, write to us and say which one.