Again the geometry is widespread, particularly so for complexes where the metal has d or d configuration. Illustrative examples include tetrakis(triphenylphosphine)palladium(0) (), nickel carbonyl (), and titanium tetrachloride ().  Many complexes with incompletely filled d-shells are often tetrahedral, e.g. the tetrahalides of iron(II), cobalt(II), and nickel(II).