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