Editing Metallocene (section)

==Spectroscopic properties==

===Vibrational (infrared and Raman) spectroscopy of metallocenes===

[[Infrared spectroscopy|Infrared]] and [[Raman spectroscopy|Raman]] spectroscopies have proved to be important in the analysis of cyclic polyenyl metal sandwich species, with particular use in elucidating covalent or ionic M–ring bonds and distinguishing between central and coordinated rings. Some typical spectral bands and assignments of iron group metallocenes are shown in the following table:<ref name="Metallocenes"/>

{| class="wikitable"
|+ Spectral frequencies of [[group 8 element|group 8]] metallocenes
! !! [[Ferrocene]] (cm<sup>−1</sup>) !! [[Ruthenocene]] (cm<sup>−1</sup>) !! [[Osmocene]] (cm<sup>−1</sup>)
|-
| C–H stretch || 3085 || 3100 || 3095
|-
| C–C stretch || 1411 || 1413 || 1405
|-
| Ring deformation || 1108 || 1103 || 1096
|-
| C–H deformation || 1002 || 1002 || 995
|-
| C–H out-of-plane bend || 811 || 806 || 819
|-
| Ring tilt || 492 || 528 || 428
|-
| M–ring stretch || 478 || 446 || 353
|-
| M–ring bend || 170 || 185 || –
|}

===NMR (<sup>1</sup>H and <sup>13</sup>C) [[spectroscopy]] of metallocenes===

[[Nuclear magnetic resonance]] (NMR) is the most applied tool in the study of metal sandwich compounds and organometallic species, giving information on nuclear structures in solution, as liquids, gases, and in the solid state. <sup>1</sup>H&nbsp;NMR chemical shifts for paramagnetic organotransition-metal compounds is usually observed between 25 and 40&nbsp;ppm, but this range is much more narrow for diamagnetic metallocene complexes, with chemical shifts usually observed between 3 and 7&nbsp;ppm.<ref name="Metallocenes"/>

===Mass spectrometry of metallocenes===
[[Mass spectrometry]] of metallocene complexes has been very well studied and the effect of the metal on the fragmentation of the organic moiety has received considerable attention and the identification of metal-containing fragments is often facilitated by the [[isotope]] distribution of the metal. The three major fragments observed in mass spectrometry are the molecular ion peak, [C<sub>10</sub>H<sub>10</sub>M]<sup>+</sup>, and fragment ions, [C<sub>5</sub>H<sub>5</sub>M]<sup>+</sup> and M<sup>+</sup>.<ref name="Metallocenes"/>