eka-protactinium

English

Etymology

eka- +‎ protactinium

Noun

eka-protactinium (uncountable)

1. Unbitrium (Ubt), an unsynthesized chemical element with atomic number 123.
2. Unquadunium (Uqu), an unsynthesized element with atomic number 141.

Usage notes

This inconsistency, between referring to element 123 versus element 141, comes from the fact the elements beyond oganesson are not known, so it is unknown what element would be placed directly below actinium.