%0 Journal Article %A Jeftic, J. %A Romstedt, H. %A Hauser, A. %T 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) %J Journal of Physics and Chemistry of Solids %@ 0022-3697 %V 57 %N 11 %P 1743-1750 %D 1996 %K inorganic compounds %K high pressure %K phase transitions %K thermodynamic properties %U http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TXR-3VS9115-1T&_user=779890&_coverDate=11%2F30%2F1996&_rdoc=25&_fmt=summary&_orig=browse&_srch=%23toc%235597%231996%23999429988%2358369!&_cdi=5597&_sort=d&_docanchor=&_acct=C000043220&_version=1&_urlVersion=0&_userid=779890&md5=d2b39cd0798bdcd8e3707db322806424 %R 10.1016/0022-3697(96)00033-9 %U http://archive-ouverte.unige.ch/unige:2976 %X 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 R3 above Tc↓ to P1 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.