Nomenclature of Elements with Atomic Number Greater than 100

When a new, superheavy element (atomic number greater than 100) is first claimed to have been synthesised, it does not yet have a permanent name — under IUPAC rules, the discovering team is invited to propose one only after the discovery has been formally confirmed and verified, which can take years. In the meantime, and for use in any general discussion before a permanent name is settled, IUPAC provides a systematic, purely numerical temporary name and symbol, derived mechanically from the digits of the element's atomic number, so that every such element can still be referred to unambiguously.

The numerical roots, one per digit 0–9, are:

To build the systematic name: write out the atomic number digit by digit, replace each digit with its root from the table above, join the roots together in order, and add the suffix "-ium" at the end. To build the three-letter symbol: take the first letter of each of the three roots used (shown in parentheses above), in the same order.

Worked example — atomic number 101. The digits are $1, 0, 1$. Their roots are un, nil, un. Joined and suffixed: Unnilunium. Its symbol is the first letters u, n, u: Unu. (This element's permanent, officially adopted name — assigned once its discovery was fully confirmed — is Mendelevium, symbol $Md$, honouring Dmitri Mendeleev.)

Worked example — atomic number 104. The digits are $1, 0, 4$. Their roots are un, nil, quad. Joined and suffixed: Unnilquadium, symbol Unq. (Its permanent name, adopted later, is Rutherfordium, $Rf$, honouring Ernest Rutherford.) …