Chemistry - Coordination Chemistry Question with Solution | TestHub
Consider these statements. (i) The C–O stretching frequency in [Ni(CO)₃(PF₃)] is higher than in [Ni(CO)₃(PMe₃)]. (ii) The C–O bond length in [Mn(CO)₆]⁺ is longer than in Cr(CO)₆. (iii) In Fe₂(CO)₉ the bridging CO stretching frequency is lower than the terminal one. (iv) The M–C bond in [V(CO)₆]⁻ is shorter than in V(CO)₆. (v) The C–O bond order in [Fe(CO)₄]²⁻ is higher than in Ni(CO)₄. Let x be the number of correct and y the number of incorrect statements. Find x × y.
Answer:
Solution:
(i) is correct because PF₃ is the stronger π-acid. (ii) is wrong because less back-donation in the cation leaves a shorter C–O bond. (iii) is correct because bridging CO is more strongly back-bonded. (iv) is correct because more back-donation shortens M–C. (v) is wrong because the dianion back-donates more, lowering the C–O bond order. x = 3, y = 2, x × y = 6.
