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