New organic conductors (BEDO-TTF)mMHg(SCN)4

Electronic properties of new quasi‐two‐dimensional organic conductors (BEDO‐TTF)5[MHg(SCN)4]2 (M = Rb, Cs) studied by IR reflectance spectroscopy at temperatures down to 10 K

“…Crystals of (BEDO-TTF) 5 [RbHg(SCN) 4 ] 2 (the Rb salt) and (BEDO-TTF) 5 [CsHg(SCN) 4 ] 2 (the Cs salt) were synthesized by electrochemical oxidation of BEDO-TTF molecules, as described in [7]. The crystal structure of the salts is composed of layers of the (BEDO-TTF) 0.4+ molecules parallel to the (ab) plane alternating with anion layers along the c axis.…”

“…In the layers, the BEDO-TTF molecules are arranged in stacks parallel to the b-2a direction with shortened S … S contacts between the neighboring molecules. Additionally, the molecules are arranged in stripes parallel to the 3b-a direction with shortened side-byside S … S contacts between the adjacent molecules in a stripe [7] (the "I 3 -type" structure [4,6]). It was shown that the "I 3 -type" structure exhibits a maximum intermolecular overlap of the BEDO-TTF electron orbitals between the stacks along the transverse and oblique directions [6], with the resulting interaction vector almost perpendicular to the stacks.…”

“…It was shown that the "I 3 -type" structure exhibits a maximum intermolecular overlap of the BEDO-TTF electron orbitals between the stacks along the transverse and oblique directions [6], with the resulting interaction vector almost perpendicular to the stacks. For the Cs salt, the positions of the counter-components are presented in [7], while for the Rb salt they are not determined because of the severe disorder of the components.…”

“…Recently, a new group of (BEDO-TTF) 5 [MHg(SCN) 4 ] 2 compounds, where M = Rb, Cs, NH 4 , has been synthesized [7]. The salts with M = Rb and NH 4 show metallic dc conductivity at temperatures down to 4 K, while the salt with M = Cs undergoes a metal-semiconductor transition at T ~ 100 K [7].…”

“…The salts with M = Rb and NH 4 show metallic dc conductivity at temperatures down to 4 K, while the salt with M = Cs undergoes a metal-semiconductor transition at T ~ 100 K [7].…”