new index atom name original index 1 C 11 2 C 13 3 C 18 4 C 15 5 C 10 6 C 12 7 C 9 8 C 16 9 C 14 10 C 17 11 N 6 12 N 8 13 N 7 14 N 5 15 O 3 16 O 2 17 O 4 18 O 1 19 H 20 20 H 21 21 H 24 22 H 25 23 H 30 24 H 26 25 H 22 26 H 23 27 H 19 28 H 28 29 H 29 30 H 27