new index atom name original index 1 C 6 2 C 7 3 C 10 4 C 5 5 C 8 6 C 9 7 O 2 8 O 4 9 O 3 10 O 1 11 H 13 12 H 14 13 H 15 14 H 16 15 H 11 16 H 12