Mixed-Valence Cobalt(II/III)–Octacyanidotungstate(IV/V)
Ferromagnet
- Publication date
- Publisher
Abstract
We report a mixed-valence cobalt(II/III)–octacyanidotungstate(IV/V)
magnet, [Co<sup>II</sup>(H<sub>2</sub>O)]<sub>2</sub>[Co<sup>III</sup>{μ-(<i>R</i>)-1-(4-pyridyl)ethanol}<sub>2</sub>][W<sup>IV</sup>(CN)<sub>8</sub>][W<sup>V</sup>(CN)<sub>8</sub>]·5H<sub>2</sub>O. Synchrotron-radiation X-ray single crystal structural analysis,
infrared spectrum, and density-functional theory (DFT) calculation
indicate that this compound has a chiral structure with the <i>P</i>2<sub>1</sub> space group and both Co<sup>II</sup>(<i>S</i> = 3/2)–NC–W<sup>V</sup>(<i>S</i> = 1/2) and Co<sup>III</sup>(<i>S</i> = 0)–NC–W<sup>IV</sup>(<i>S</i> = 0) moieties, which are structurally
distinguishable in the crystal structure. Magnetic measurements reveal
that this compound exhibits ferromagnetism with a Curie temperature
of 11 K and a coercive field of 1500 Oe, which is caused by the coexistence
of the superexchange interaction in the Co<sup>II</sup>–W<sup>V</sup> chain and double exchange interaction between the chains
