The IUPAC Rules
| digit | root | symbol |
|---|---|---|
| 0 | nil | n |
| 1 | un | u |
| 2 | b(i) | b |
| 3 | tr(i) | t |
| 4 | quad | q |
| 5 | pent | p |
| 6 | hex | h |
| 7 | sept | s |
| 8 | oct | o |
| 9 | en(n) | e |
The temporary names are derived systematically from the element's atomic number. Each digit is translated to a 'numerical root', according to the table to the right. 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 two digits starting with the same letter (Ex: 0 = nil, 9 = nona, 4 = quad, 5 = quin, 6 = sex, 7 = sept) . There are two elision rules designed to prevent odd-looking names.
- If bi or tri is followed by the ending ium (i.e. the last digit is 2 or 3), the result is '-bium' or -'trium', not '-biium' or '-triium'.
- If enn is followed by nil (i.e. the sequence -90- occurs), the result is '-ennil-', not '-ennnil-'.
The systematic symbol is formed by taking the first letter of each root, converting the first to a capital.
The suffix -ium overrides traditional chemical suffix rules, thus 117 and 118 are ununseptium and ununoctium, not ununseptine and ununocton.
All elements up to atomic number 112 and elements 114 and 116 have received individual permanent names and symbols. So the systematic names and symbols are only used for unnamed elements 113, 115, 117 and higher. The systematic names are exactly those with 3-letter symbols.
Read more about this topic: Systematic Element Name
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“Rules and particular inferences alike are justified by being brought into agreement with each other. A rule is amended if it yields an inference we are unwilling to accept; an inference is rejected if it violates a rule we are unwilling to amend. The process of justification is the delicate one of making mutual adjustments between rules and accepted inferences; and in the agreement achieved lies the only justification needed for either.”
—Nelson Goodman (b. 1906)