Electronic Properties of a TMTTF-Family Salt, (TMTTF)₂TaF₆: New Member Located on theModifiedGeneralized Phase-Diagram

Comprehensive Optical Investigations of Charge Order in Organic Chain Compounds (TMTTF)2X

“…According to Yamamoto et al [103] the maximum influence of the second term is at 0.85e, implying that for such kind of charge-ordered system the effect must be even stronger. To support this interpretation, it would be desirable to conduct an infrared study on the new synthesized organic salt (TMTTF) 2 TaF 6 [107] where the transition temperature is at T CO = 175 K, connected with a larger charge imbalance. Here we could show that from the overtones and the combination modes we can gain further insight into the electronic interaction; in general they can be used to observe the onset of the charge ordering.…”

Conservation of structural arrangements and 3 : 1 stoichiometry in a series of crystalline conductors of TMTTF, TMTSF, BEDT-TTF, and chiral DM-EDT-TTF with the oxo-bis[pentafluorotantalate(v)] dianion

“…Moreover, Nakamura et al mentioned in their report on (TMTTF) 2 TaF 6 the formation of (TMTTF) 3 Ta 2 F 10 O as a secondary phase. 15 All these experimental facts, combined with chemical reactivity issues, strongly suggest that the occurrence of the [Ta 2 F 11 ] À monoanion in these salts is very unlikely. Last but not least, a common sense argument could be evoked as well.…”

“…[10][11][12] Particularly interesting is the evolution of the critical temperature T c for the superconducting transition with the applied pressure and the anion size in the (TMTSF) 2 XF 6 Bechgaard salts 8,13,14 and also the variation of the charge ordering transition temperature T CO in the Fabre salts (TMTTF) 2 XF 6 (X ¼ P, As, Sb, Ta) with the anion size, as a consequence of the chemical pressure exerted by the anion. 15 For example, T CO values are 65 K, 100 K, 155 K and 175 K for PF 6 À , AsF 6 À , SbF 6 À and TaF 6 À , respectively. 15 Interestingly, while Bechgaard and Fabre salts are isostructural, 5,13,16 2 : 1 mixed valence salts of bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF), another agship donor in the eld of organic conductors and superconductors, 2,17,18 with octahedral monoanions XF 6 À show, in comparison, a rich collection of structures and, consequently, physical properties.…”

“…15 For example, T CO values are 65 K, 100 K, 155 K and 175 K for PF 6 À , AsF 6 À , SbF 6 À and TaF 6 À , respectively. 15 Interestingly, while Bechgaard and Fabre salts are isostructural, 5,13,16 2 : 1 mixed valence salts of bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF), another agship donor in the eld of organic conductors and superconductors, 2,17,18 with octahedral monoanions XF 6 À show, in comparison, a rich collection of structures and, consequently, physical properties. Indeed, triclinic and orthorhombic phases have been described for a-(BEDT-TTF) 2 -PF 6 19 and b-(BEDT-TTF) 2 PF 6 , 20 respectively, monoclinic 21 and orthorhombic 22 structures for b-(BEDT-TTF) 2 AsF 6 , a monoclinic phase for b-(BEDT-TTF) 2 SbF 6 , 23 isostructural to the AsF 6 À counterpart, and, nally, monoclinic and orthorhombic structures for d-(BEDT-TTF) 2 TaF 6 , 24 together with a monoclinic k-(BEDT-TTF) 2 TaF 6 phase.…”

Characterization of the quasi-one-dimensional compounds δ-(EDT-TTF-CONMe2)2X, X=AsF6 and Br by vibrational spectroscopy and density functional theory calculations

“…The transition temperature can be tuned by chemical or hydrostatic pressure. 4,5 A deeper understanding of the charge ordering and its driving force will shed new light on the development of chemically tailored compounds and possible functional molecular devices. There is an ongoing discussion if the dimerization and hence the 1 2 Umklapp scattering cause or destabilize the charge ordering.…”