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