CALORIMETRIC STUDIES ON DMEFC!TCNE! AND DMEFC!TCNQ!

Authors
NAKANO M SORAI M
Citation
M. Nakano et M. Sorai, CALORIMETRIC STUDIES ON DMEFC!TCNE! AND DMEFC!TCNQ!, Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals, 232, 1993, pp. 521-530
Citations number
18
Categorie Soggetti
Crystallography
Journal title
Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals → ACNP
ISSN journal
1058725X
Volume
232
Year of publication
1993
Pages
521 - 530
Database
ISI
SICI code
1058-725X(1993)232:<521:CSOA>2.0.ZU;2-I
Abstract
Typical molecular-based magnets, decamethylferrocenium tetracyanoethen ide (DMeFc!TCNE!) and decamethylferroccnium tetracyanoquinodimethani de (DMeFc!TCNQ!), have been studied by means of adiabatic calorimetr y. The Curie temperature of DMeFc!TCNE! was determined to be T(c) = 4.74 K. The excess entropy derived from the observed heat-capacity ano maly was very close to the expected magnetic entropy, 2 R In 2. Detail ed analysis of the heat-capacity anomaly revealed that DMeFc!TCNE! i s a good one-dimensional (1D) Ising magnet. Two structural phase trans itions were found for the first time at 248.7 and 281.8 K, and attribu ted to the orientational order-disorder character of the TCNE anion. F or DMeFc!TCNQ! an antiferromagnetic phase transition was observed at T(N) = 2.54 K. The magnetic lattice anisotropy of the TCNQ salt is sm aller than that of the TCNE salt.