text: With metals in group 4 or 5 a so-called edge-capped octahedral clusters are more common. Twelve halides are located along the edge of the octahedron and six are terminal.  Examples of this structure type are tungsten(III) chloride, TaCl(HO), NbF, and NbF.
  Many of the early metal clusters can only be prepared when they incorporate interstitial atoms.  One example is ZrCCl.