Reduction as well as oxidation of the cyclo-As8 complex [{Cp’’Ta}2(µ,η2:2:2:2:1:1-As8)] (A, Cp’’ = 1,3-tBu2C5H3) are demonstrated to afford controlled dimerisation to unprecedented As16 species. The dication [{Cp’’Ta}4(µ4,η2:2:2:2:2:2:2:2:1:1:1:1-As16)]2+ slowly disproportionates in solution, yielding the largest polyarsenide species in a molecular complex known to date.
