- Phase transitions in iron(II) hexafluorosilicate and perrhenate complexes with 4-amino-1,2,4-triazole
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The heat capacity and magnetic susceptibility of iron(II) hexafluorosilicate and perrhenate coordination compounds with 4-amino-1,2,4-triazole (A), FeA3SiF6·H2O (I) and FeA3(ReO4)2 (II), were measured in the temperature range 80-350 K. The 1A1 ? 5T2 spin transition was observed in I and II. The magnetochemical data were used to determine the transition temperatures during heating (255 and 228 K for I and II, respectively). Heat capacity anomalies with maxima at 251 K for I and 231 K for II well correlated with magnetic susceptibility measurements. The enthalpies and entropies of spin transitions were determined for both compounds. One more anomaly with a maximum at 323 K was observed for I. This anomaly might be caused by a change in the structure of the anion during heating.
- Berezovskii,Shakirova,Shvedenkov,Lavrenova
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p. 1054 - 1058
(2007/10/03)
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