Complex sentence: Astatine, which is included here, is irregularly recognised as a metalloid but we decided quite a while go to recognise it a metalloid noting it has since been predicted to have the band structure of a full-blown metal.
Split into simpler sentences: Astatine, which is included here, is irregularly recognised as a metalloid but we decided quite a while go to recognise it a metalloid. It has since been predicted to have the band structure of a full-blown metal.