text: Metal halides are often readily available precursors for other inorganic compounds. Mentioned above, the halide compounds can be made anhydrous by heat, vacuum, or treatment with thionyl chloride.
  Halide ligands may be abstracted by silver(I), often as the tetrafluoroborate or the hexafluorophosphate. In many transition metal compounds, the empty coordination site is stabilized by a coordinating solvent like tetrahydrofuran. Halide ligands may also be displaced by the alkali salt of an X-type ligand, such as a salen-type ligand. This reaction is formally a transmetallation, and the abstraction of the halide is driven by the precipitation of the resultant alkali halide in an organic solvent. The alkali halides generally have very high lattice energies.
  For example, sodium cyclopentadienide reacts with ferrous chloride to yield ferrocene:
  :2 NaCH + FeCl → Fe(CH) + 2 NaCl
  While inorganic compounds used for catalysis may be prepared and isolated, they may at times be generated in situ by addition of the metal halide and the desired ligand. For example, palladium chloride and triphenylphosphine may be often be used in lieu of bis(triphenylphosphine)palladium(II) chloride for palladium-catalyzed coupling reactions.