new index atom name original index 1 C 8 2 C 5 3 C 6 4 C 9 5 C 7 6 O 3 7 O 4 8 O 2 9 O 1 10 H 14 11 H 16 12 H 15 13 H 10 14 H 11 15 H 12 16 H 13 17 H 17