7-Oxaspiro[5.9]pentadecane-1,8,13-trione

The crystal structure of the title compound, C 14 H 20 O 4 , a macrocyclic lactone, is composed of independent molecules with normal molecular dimensions. The average bond distances are C sp 3-C sp3 1.526(6), C sp 3-C sp 2 1.514(14) and C=O 1.210(3)A. The six-membered ring adopts a chair conformation, while the ten-membered heterocyclic ring is in a boat-chair-boat (bcb) conformation. There are no unusual interactions between the molecules which are separated by normal van der Waals distances.