new index atom name original index 1 C 15 2 C 14 3 C 12 4 C 13 5 C 9 6 C 10 7 C 6 8 C 11 9 C 7 10 C 5 11 C 8 12 N 4 13 O 3 14 O 1 15 O 2 16 H 25 17 H 26 18 H 27 19 H 24 20 H 22 21 H 23 22 H 20 23 H 21 24 H 17 25 H 18 26 H 16 27 H 19 28 H 28