Arylstibonic acids [H-8(RSb)(12)O-28]; precursors to organometallic isopolyoxostibonates [Na2H9(RSb)(12)O-30](-), (R = aryl)

Electrospray ionisation mass spectrometry shows that arylstibonic acids, RSbO3H2, give rise to oxo-bridged clusters derived from [H-8(RSb)(12)O-28] which act as inorganic crown ligands towards Na+ cations; structure determination of one derivative revealed a cage-like anion [Na2H9(p-O2NC6H4Sb)(12)O-30 center dot 4H(2)O](-).