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