new index atom name original index 1 C 12 2 C 10 3 C 11 4 C 7 5 C 8 6 C 6 7 C 5 8 C 4 9 C 9 10 O 1 11 O 2 12 O 3 13 H 20 14 H 18 15 H 19 16 H 16 17 H 17 18 H 14 19 H 15 20 H 13 21 H 21 22 H 22