Pentagonal bipyramidal structures antimony

The Sb(C204)3- ion forms isolable salts and has been shown to have the i//-pentagonal-bipyramid structure (Fig. 13-1 la) with a lone pair at one axial position.66 The tartrate complexes of antimony(in) have been much studied as tartar emetic has been used medicinally for over three hundred years. This potassium salt and salts of NH4 and [Fe(phen)3]2+ are known to have a binuclear structure with tartrate bridges as shown in Fig. 13-1 lb.67... 

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