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The Graphic Representation of Chemical Formulae in the Publications of International Nonproprietary Names (INN) for Pharmaceutical Substances
(1995; 53 pages) View the PDF document
Table of Contents
View the documentAcknowledgements
View the document1. INTRODUCTION
View the document2. ACYCLIC STRUCTURES
View the document3. CYCLIC STRUCTURES
View the document4. IONIC STRUCTURES
View the document5. ISOTOPICALLY MODIFIED COMPOUNDS
View the document6. COORDINATION COMPOUNDS
View the document7. STEREOCHEMISTRY
View the document8. CARBOHYDRATES
View the document9. STEROIDS
View the document10. TERPENOIDS
View the document11. PROSTANOIDS
View the document12. ALKALOIDS
View the document13. ANTIBIOTICS
View the document14. POLYPEPTIDES
View the document15. POLYMERS
View the documentAcknowledgements
View the documentReferences
 

5. ISOTOPICALLY MODIFIED COMPOUNDS

5.1 In an isotopically modified compound, the isotope used is indicated by its mass number placed as a superscript on the left of the symbol of the element concerned. Deuterium and tritium are written 2H and 3H respectively. The carbon atom in a ring or in a simplified angular-chain representation is explicitly designated when its mass number is shown:

5.2 When atomic symbols in formulae are drawn without square brackets (as above) the compounds are assumed to be isotopically substituted, i.e. the atom concerned is completely replaced by the nuclide shown. To indicate isotopic labelling (partial replacement of the atom by the nuclide shown), atomic symbols in formulae should be in square brackets:

 

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