A thirty-year old mystery solved: identification of a new heptatungstate from non-aqueous solutions.

A new isopolyoxotungstate has been characterised, thirty years since the first spectroscopic evidence of its existence. The heptatungstate [W 7 O 24 H] 5- , containing a {W 5 } lacunary Lindqvist unit fused to a ditungstate fragment, has significant stability and is only the third isopolytungstate structure to be obtained from non-aqueous systems.