The +7 state for Mn is not represented in simple halides but
MnO3F is known, and beyond Mn no metal has a trihalide except FeX3
and CoF3 The ability of fluorine to stabilise the highest oxidation state is
due to either higher lattice energy as in the case of CoF3, or higher bond
enthalpy terms for the higher covalent compounds, e g , VF5 and CrF6