Nine-vertex metallaborane chemistry. Preparation and characterisation of [1,1,1-(PMe3)2H-isocloso-IrB8H7-8-X], where XÂ =Â H or Cl

► Characterization of the only two known nine-vertex isocloso metallaboranes. ► DFT and XHYDEX calculations locate the terminal metal hydride positions. ► The fluxional process in the clusters is investigated by DFT calculation. ► The energies of the isocloso species and their closo isomers are compared by DFT.