new index atom name original index 1 C 10 2 C 5 3 C 6 4 C 7 5 C 4 6 C 8 7 C 9 8 N 3 9 O 2 10 O 1 11 H 26 12 H 24 13 H 25 14 H 21 15 H 19 16 H 20 17 H 18 18 H 17 19 H 16 20 H 15 21 H 13 22 H 14 23 H 11 24 H 12 25 H 22 26 H 23