21. N2 can act as a ligand in a similar way as CO. In comparison to CO, which of the following is true?[2 pts]
(A)It is a better σ donor and i acceptor.
(B) It is a better σ donor but poorer tt acceptor.
(C) It is a poorer σ donor but a better x acceptor.
(D) It is a poorer σ donor and it acceptor.
(E) None of above is correct
答案：99
統計：A:0,B:0,C:0,D:0,E:0
難度：計算中