new index atom name original index 1 C 7 2 C 6 3 C 8 4 C 4 5 C 1 6 C 10 7 N 5 8 N 12 9 N 9 10 O 2 11 O 3 12 O 11 13 H 19 14 H 20 15 H 17 16 H 18 17 H 21 18 H 22 19 H 14 20 H 15 21 H 16 22 H 24 23 H 25 24 H 23 25 H 13