The approximate positions of $\nu_{\mathrm{co}}$ bands $(\mathrm{cm^{-1}})$ in the solid-state infrared spectrum and the Fe-Fe bond order in $\mathrm{[Fe(\eta^{5}\text{-}C_5H_5)(\mu\text{-}CO)(CO)]_2}$ (non-centrosymmetric) respectively,are
(a)(2020, 1980, 1800) and one
(b)(2020, 1980, 1800) and two
(c)$(2020,1980)$ and one
(d)(2143) and one
Answer
Answer (as printed): A
Explanation
Terminal CO $=2120\text{–}1850\,\mathrm{cm^{-1}}$$\mu_2\text{-CO}=1850\text{–}1750\,\mathrm{cm^{-1}}$In this complex M–M bond order = 1 and two types of CO's terminal as well as bridging.So, $\nu_{\mathrm{CO}}$ band lies in both range.