Crown compounds containing only oxygen as coordinating atom.
| Member | Definition | Role |
|---|
| 12-crown-4 | A crown ether that is cyclododecane in which the carbon atoms at positions 1, 4, 7 and 10 have been replaced by oxygen atoms. | 12-crown-4 |
| 15-crown-5 | A saturated organic heteromonocyclic parent that is cyclopentadecane in which the carbon atoms at positions 1, 4, 7, 10 and 13 have been replaced by oxygen atoms to give a crown ether. | 15-crown-5 |
| 18-crown-6 | A crown ether that is cyclooctadecane in which the carbon atoms at positions 1, 4, 7, 10, 13 and 16 have been replaced by oxygen atoms. | 18-crown-6 |
| dibenzo-18-crown-6 | A crown ether that is 18-crown-6 ortho-fused to two benzene rings at positions 8-9 and 17-18. | dibenzo-18-crown-6 |