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Title

Interplay between the spin transition and the crystallographic phase transition in the Fe(II) spin-crossover system [Zn1-xFex(ptz)6](BF4)2 (x = 0.1, 1; ptz = 1-propyltetrazole)

Authors
Romstedt, Harald
Published in Journal of Physics and Chemistry of Solids. 1996, vol. 57, no. 11, p. 1743-1750
Abstract In the [Fe(ptz)6](BF4)2 (ptz = 1-propyltetrazole) spin-crossover system, the thermal spin transition is accompanied by a first order crystallographic phase transition (Tc↓ = 128 K and Tc↑ = 135 K) from RImage above Tc↓ to PImage at low temperatures (Wiehl L., Acta Cryst. B49, 289 (1993)). The high-symmetry phase can be super-cooled, in which case the spin transition is still complete and quite steep (T1/2 = 125 ± 2 K) but now without a hysteresis. The corresponding interaction constant Γ is 170 cm−1. In the diluted system [Zn1−xFex(ptz)6](BF4)2, X = 0.1, the spin transition is gradual with T1/2 = 95 ± 2 K. From the shift of T1/2 towards high temperatures with external pressure a value for ΔVHL0 of 26 Å3 molecule−1 is obtained. Pressures above 250 bar induce a crystallographic phase transition even in the diluted system, as a result of which the spin transition is discontinuous. The interplay between the thermal spin transition and the crystallographic phase transition in the neat and the diluted system is discussed consistently.
Keywords Inorganic compoundsHigh pressurePhase transitionsThermodynamic properties
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Research group Groupe Hauser
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JEFTIC, Jelena, ROMSTEDT, Harald, HAUSER, Andreas. Interplay between the spin transition and the crystallographic phase transition in the Fe(II) spin-crossover system [Zn1-xFex(ptz)6](BF4)2 (x = 0.1, 1; ptz = 1-propyltetrazole). In: Journal of Physics and Chemistry of Solids, 1996, vol. 57, n° 11, p. 1743-1750. https://archive-ouverte.unige.ch/unige:2976

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Deposited on : 2009-09-21

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