Bond valence sums and structural studies of antimony complexes containing Sb bonded only to O ligands

New R0 values for Sb(III)-O of 1.955(13) Å and for Sb(V)-O of 1.912(12) Å have been determined. Examples where the BVS calculation of the oxidation state does not agree with the postulated value are discussed. The synthesis and structure of two new potassium antimony tartrate complexes are reported. One complex has the unusual 1:2 ratio of Sb to tartrate that was suggested did not exist.