new index atom name original index 1 C 8 2 C 9 3 C 10 4 C 11 5 C 12 6 C 13 7 C 14 8 N 15 9 O 16 10 O 17 11 H 1 12 H 2 13 H 3 14 H 4 15 H 5 16 H 6 17 H 7