TS EN ISO 80000-9

TS EN ISO 80000-9 is the part of the Quantities and units series that organises the names, symbols, definitions and units used in physical chemistry and molecular physics. In practice, it provides a consistent language for quantities associated with molecular structure, intermolecular interactions, mixtures, chemical equilibrium and related measurement work.

A common language for chemistry and molecular-scale physics

In general technical use, physical chemistry deals with the quantitative behaviour of matter through energy changes, phase behaviour, reaction equilibrium and transport properties, while molecular physics focuses on the motion, interaction and statistical behaviour of atoms and molecules. In these fields, inconsistent naming or symbol use can quickly lead to ambiguity in calculations and data exchange. This standard therefore serves as a shared reference for terminology and symbol usage.

What this part covers

• Names and symbols for quantities used in physical chemistry and molecular physics
• Definitions of those quantities
• Units where appropriate
• Conversion factors where appropriate

Rather than prescribing a test method or a specific instrument, the standard is aimed at harmonising the basic language of measurement and calculation. That makes it easier to read laboratory reports, technical documentation, databases and teaching material in a consistent way.