deuterium

https://doi.org/10.1351/goldbook.D01648
A specific name for the atom 2H. The cation 2H+ is a deuteron the species 2H− is a deuteride anion and 2H is the deuterio group.
Source:
PAC, 1988, 60, 1115. 'Names for hydrogen atoms, ions, and groups, and for reactions involving them (Recommendations 1988)' on page 1116 (https://doi.org/10.1351/pac198860071115)