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