1991 Fiscal Year Final Research Report Summary

About the abnormal Valence of the Transition Metal in The CT complex

Research Project

Project/Area Number	02640338
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	物理化学一般
Research Institution	Nagoya University
Principal Investigator	TANAKA Masashi Nagoya University, College of Genral Education, Professor, 教養部, 教授 (70022639)
Project Period (FY)	1990 – 1991
Keywords	BEDT-TTF / conductivity / phase transition / ESR / 混合原子価
Research Abstract	Bis (ethylenedithio) tetrathiafulvalene (BEDT-TTF) forms many charge transfer complexes. The crystal of (BEDT-TTF)_4 [Ni(CN)_4] belongs to the triclinic pl with the lattice constants of a=10.994 (2), b=16.443 (2), c=9.703 (1), alpha=97.85 (1), beta=115.15 (1), gamma=95.94 (1)ﾟ. In the crystal, there exists the face to face overlap of the BEDT-TTF molecules along the [201] direction. The intermolecular interaction by the short S ・・・ S contact is also observed along the [201] direction. The room temperature conductivity was about 20S/cm. The crystal was metellic between 230 and 300K and became semi-conductive with an energy gap of 100K below 160K, although the temperature dependence of the conductivity was not obtween 160 and 230K. This kind of resistance behavior may be explained by the phase transition of the crystal between 160 and 230K. The ESR spectrum at 4K consists of the strong band at g=2.013 and the weak band at g=2.056.