Assertion: carbon | /r/HasProperty | 12 o 9 6−
Facets:
Source sentences:
text: Other more exotic carbon–oxygen anions exist, such as acetylenedicarboxylate (O 2 C–C≡C–CO 2 2−), mellitate (C 12 O 9 6−), squarate (C 4 O 4 2−), and rhodizonate (C 6 O 6 2−).