Thermal propertiesD 3000 DOI: 10.1002/chin.201140003

Giant Negative Thermal Expansion in the Iron Perovskite SrCu3Fe4O12. — Poly-crystalline SrCu3Fe4O12 is synthesized from a stoichiometric mixture of Sr(NO3)2, Cu(NO3)2, Fe(NO3)3, and a fivefold molar excess of citric acid dissolved in a mixture of water and ethanediol (433 K, ≈12 h) followed by decomposition of the resulting solid at 723 and 973 K. The obtained precursor is mixed with KClO4 and treated at 1273 K and 15 GPa for 15 min. SrCu3Fe4O12 exhibits negative thermal expansion be-havior with a linear expansion coefficient of -2.26·10-5 K-1, which is comparable with the largest value reported to date. The large negative thermal expansion is explained by a strong internal compression of the Sr ion in the novel perovskite. The results demon-strate the strong influence of the A site cation in ACu3Fe4O12 perovskites on the elec-tronic and structural properties. — (YAMADA*, I.; et al.; Angew. Chem., Int. Ed. 50 (2011) 29, 6579-6582, http://dx.doi.org/10.1002/anie.201102228 ; Dep. Chem., Fac. Sci., Ehime Univ., Matsuyama, Ehime 790, Japan; Eng.) — W. Pewestorf

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