Fig. 14. Phosphotungstate anion [PW12O40]3−. O, red; P, orange; W, blue. A central tetrahedral PO4 surrounded by 12 octahedral W(vi)O6, with bridging and terminal surface oxygens. This is the major component of phosphotungstic acid at pH 1. It is used in histology for staining of cells; it binds to fibrin, collagen, and connective tissues. Reproduced from https://en.wikipedia.org/wiki/Phosphotungstic_acid with permission from author (Benjah-bmm27).
