Jahn-Teller distortion of the open-shell 23-electron chalcogenide rhenium cluster cores in crystals of the series, ([Re6Q8]3+(X-)6)3- (Q = S, Se; X = Cl, CN).
Comparison within the title [Re6Q8X6]4-/[Re6Q8X6]3- redox series of 14 precise crystal structures of the Re6 cluster cores at different low temperatures reveals that the one-electron oxidised, open-shell (23 electron) cores undergo a Jahn-Teller distortion of their parent 24 electron octahedral cores and that D4h and D2h forms may co-exist in the solid state.