Qualitatively and quantitatively different solvatochromism of the MLCT and MMCT absorption bands of centrosymmetric acceptor-bridged diiron(II,II) and diiron(III,II) cyanide complexes. Inorganica Chimica Acta, (336):55--60, 2002. [PUMA: cyano transfer charge absorption iron complex mixed valence solvatochromism]