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