Mixed valency and magnetism in cyanometallates and Prussian blue analogues

• Published in: Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences Vol. 366; no. 1862; pp. 127 - 138
• Main Authors: Herrera, J.M, Bachschmidt, A, Villain, F, Bleuzen, A, Marvaud, V, Wernsdorfer, W, Verdaguer, M
• Format: Journal Article
• Language: English
• Published: London The Royal Society 13-01-2008
• Subjects: Chromium; Cyanides; Cyanometallates; High; high T C molecule-based magnets; Magnetic dipole moment; Magnetic fields; Magnetism; Magnetization; Magnets; Mixed Valency; Molecule-Based Magnets; Molecules; Photomagnetic High-Spin Molecules; Photomagnetism; Prussian Blue Analogues; Transition metals; Vanadium
• ISSN: 1364-503X; 1471-2962
• DOI: 10.1098/rsta.2007.2145

O (C alkali cation, A and B transition metal ions) and other metallic cyanometallates {C
O (L ligand), the presence of two valency states in the solid (either A–B, or A–A′ or B–B′) is crucial to get original magnetic
properties: tunable high Curie temperature magnets; photomagnetic magnets; or photomagnetic high-spin molecules. We focus
on a few mixed valency pairs: V(II)/V(III)/V(IV); Cr(II)/Cr(III); Fe(II)–Fe(III); Co(II)–Co(III); Cu(I)–Cu(II); and Mo(IV)/Mo(V),
and discuss: (i) the control of the degree of mixed valency during the synthesis, (ii) the importance of mixed valency on
the local and long-range structure and on the local and macroscopic magnetization, and (iii) the crucial role of the cyanide
ligand to get these original systems and properties.
Prussian blue (PB) is a well-known archetype of mixed valency systems. In magnetic PB analogues {C