Synthesis and Magnetic Characterization of Salts of the Dimeric Chromium(III) Cation mu-sulfato-di-mu-hydroxobis[{N,N'-bis(2-pyridylmethyl)-amine}chromium(III)]. Crystal Structure of the Dithionate Salt, [(bispicam)Cr(OH)2(SO4)Cr(bispicam)](S2O6).3H2O.