new index atom name original index 1 C 9 2 C 5 3 C 4 4 C 1 5 N 3 6 N 7 7 N 2 8 O 6 9 O 8 10 H 16 11 H 17 12 H 18 13 H 11 14 H 12 15 H 10 16 H 13 17 H 14 18 H 15