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