| 2026-04-21 | Chemical "twin" |
| 2026-01-04 | Chemist's variant |
| 2025-10-22 | Molecule with a non-unique formula |
| 2025-02-04 | Molecule that shares its formula with another |
| 2024-12-16 | Compound with the same number of atoms in a different arrangement |
| 2022-06-06 | Similar chemical compound |
| 2022-02-05 | Compound with a chemical "twin" |
| 2019-05-13 | Chemical cousin |
| 2019-03-07 | Chemical variation |
| 2016-05-04 | Chemical cousin |
| 2014-04-22 | Chemical "twin" |
| 2013-05-10 | Chemistry test topic |
| 2008-11-23 | Compound variant |
| 2008-10-18 | Chemical relative |
| 2008-03-30 | Chemical cousin |
| 2006-06-25 | Chemical "twin" |
| 2006-04-07 | Glucose, to fructose |
| 2006-03-19 | Diethyl ether, to butanol |
| 2004-03-12 | Chemistry test topic |
| 2001-09-03 | Chemical cousin |
| 1997-08-23 | One of chemically related compounds |
| 1997-05-15 | Fraternal twin, in chemistry |
| 1997-02-06 | Ethanol, to dimethyl ether |
| 1995-12-19 | Chemical relative |
| 1995-10-29 | Related compound |
| 1995-08-03 | Chemical relative |