Transition elements like iron are most commonly found in octahedral and tetrahedral coordination environments. Linear, trigonal-bipyramidal, square-planar, and cubic coordination also occur. The links below show typical vibrational motions for molecules with some of these geometries. Most of the animations show electronically neutral, gas phase molecules with the highest possible symmetry. The animations should reasonably approximate vibrational motions of complexes that are less symmetric or otherwise complicated because they are charged, in solution or part of a weak crystal lattice. Vibrational motions were calculated by normal-coordinate analysis with the ab initio electronic structure packages GAMESS and Gaussian03. Joseph Ochterski has written a good tutorial explaining in detail how an ab initio software package (in this case, Gaussian 03) calculates vibrational frequencies and motions.
CF4, [FeCl4]-, CH4, CHClF2, CCl2F2 or CCl3F
SF6 or [Cr(H2O)6]3+
Quicktime movies of the molecular vibrations were created with MacMolPlt. The Quicktime movies were converted to animated GIFs using GIFbuilder 1.0 and GraphicConverter 4.0.7. Vibrations in Hg(CH3)2 and ReF7 are animated using the Java applet Jmol. It may be necessary to update your computer's Java installation before viewing the Jmol animations.
Other GIFs of molecular vibrations:
HF and HCl , from an example calculation predicting stable isotope fractionations using vibrational spectra.
The symmetric Fe-O stretch of [FeIII(H2O)6]3+ in solution. This is a stereo image (cross your eyes to see the 3D effect).