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