TS ISO 80000-9

TS ISO 80000-9 is the part of the quantities-and-units series devoted to physical chemistry and molecular physics. It provides the terminology framework for expressing the names, symbols and unit notations used in this field in a consistent way, so that chemical and molecular quantities can be written in alignment with the broader SI-based language used across science and engineering.

In general technical terms, physical chemistry studies matter through energy, equilibrium, transformation and interactions at the particle level. Molecular physics focuses on the structure, motion and interactions of atoms and molecules. In these areas, clear naming of quantities such as temperature, pressure, amount of substance, mole fraction, concentration and related derived quantities matters because it supports unambiguous calculations and reliable data exchange.

How quantities and units are organised in this subject area

A quantities-and-units standard of this kind helps reduce the risk that the same concept will be labelled differently across laboratories, textbooks or technical reports. This is especially important for derived quantities, where an incorrect symbol or unit choice can quickly lead to errors. A common terminology base is therefore valuable in scientific reporting, education, measurement documentation and computational workflows.

This listing also represents a withdrawn edition based on ISO 80000-9:2013. It should therefore be understood as a reference for the subject area and its conceptual unit language, not as a source for specific test methods, numerical limits or equipment requirements that would need explicit clause-level evidence.

• Consistent naming of chemical and molecular quantities
• SI-aligned symbols and unit notation
• Common language for scientific publications and measurement records
• Comparable expression of physical chemistry data