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