Octachlorodimolybdate ($[\mathrm{M}{\mathrm{o}}_2\mathrm{C}{\mathrm{l}}_8{]}^{4-}$)

The idealized eclipsed ion $[\mathrm{M}{\mathrm{o}}_2\mathrm{C}{\mathrm{l}}_8{]}^{4-}$ has two formally Mo(II), d${}^4$ centres and a quadruple bond. Each metal has four chloride ligands arranged approximately in a square.