In chemistry, heavy transuranic elements receive a permanent name and symbol only after their discovery has been confirmed. This has been a protracted and highly political process in some cases (see element naming controversy). In order to discuss newly discovered and as-yet undiscovered elements without ambiguity, the IUPAC assigns a provisional name and symbol to such elements.

The IUPAC rules

The provisional names are derived systematically from the element's atomic number. Each digit is translated to a 'numerical root', according to the table. The roots are concatenated, and the name is completed with the ending -ium. Some of the roots are Latin and others are Greek; the reason is to avoid duplicated letters. Some extra rules are designed to prevent funny-looking names.

• If bi or tri is followed by the ending ium, one of the two i's is omitted.
• If enn is followed by nil, one of the three n's is omitted.

The provisional symbol is formed by taking the first letter of each root, converting the first to a capital.

All elements up to and including atomic number 111 have received permanent names and symbols, so the use of provisional names and symbols is recommended only for elements 112 and above. Therefore, in practice, provisional names are just those with 3-letter symbols.