An isomer that differs in the position of its isotopic
substitutions. The three isotopomers of C2H5DO
are shown below:
H H H H H D
| | | | | |
H-C-C-O-D D-C-C-O-H H-C-C-O-H
| | | | | |
H H H H H H
Isotopomers should not be confused with
isotopologues.
http://www.iupac.org/goldbook/I03352.pdf