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