Title: refractive index
Long Title: IUPAC Gold Book - refractive index
DOI: 10.1351/goldbook.R05240
Status: current
Index: quantity

Definition
The ratio of the speed of light in vacuum to that in a given medium.

Sources
- Green Book, 2nd ed., p. 30 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)
- PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 989 (https://doi.org/10.1351/pac199668040957)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/R05240/html
- json: https://goldbook.iupac.org/terms/view/R05240/json
- xml: https://goldbook.iupac.org/terms/view/R05240/xml

Citation: Citation: 'refractive index' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.R05240
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Accessed: 2026-08-09T21:42:59+00:00