Stable Molecular Metal [ Pd(dddt)$_{\bf 2}$] Ag$_{\bf 1.54}$Br$_{\bf 3.50}$: Synthesis, Crystal Structure, Transport Properties and Electronic Band Structure

L.A. Kushch; S.V. Konovalikhin; L.I. Buravov; A.G. Khomenko; G.V. Shilov; K. Van; O.A. Dyachenko; E. B. Yagubskii; C. Rovira; E. Canadell

doi:doi:10.1051/jp1:1996173

Issue		J. Phys. I France Volume 6, Number 12, December 1996


Page(s)		1555 - 1565
DOI		https://doi.org/10.1051/jp1:1996173

DOI: 10.1051/jp1:1996173
J. Phys. I France 6 (1996) 1555-1565

Stable Molecular Metal [ Pd(dddt) $_{\bf 2}$ ] Ag $_{\bf 1.54}$ Br $_{\bf 3.50}$ : Synthesis, Crystal Structure, Transport Properties and Electronic Band Structure

L.A. Kushch¹, S.V. Konovalikhin¹, L.I. Buravov¹, A.G. Khomenko¹, G.V. Shilov¹, K. Van², O.A. Dyachenko¹, E. B. Yagubskii¹, C. Rovira³ and E. Canadell^{4, 5}

¹ Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences, Chernogolovka MD, 142432 Russia
² Institute of Experimental Mineralogy, Russian Academy of Sciences, Chernogolovka MD, 142432 Russia
³ Deparament de Quìmica Física, Facultat de Quìmica, Universitat de Barcelona, 08028 Barcelona, Spain
⁴ Institut de Ciencia de Materials de Barcelona (CSIC), Campus de la UAB, 08193 Bellaterra, Spain
⁵ Laboratoire de Structure et Dynamique des Systèmes Moléculaires et Solides, Université de Montpellier II, 34095 Montpellier Cedex, France

(Received 5 March 1996, accepted 11 June 1996)

Abstract
The synthesis, crystal and electronic band structures as well as conducting properties of the new stable molecular metal [ Pd(dddt) ₂] Ag _1.54Br _3.50 (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolato) are reported. the crystal structure contains layers of donor cations alternating with layers of silver bromide complex anions along the a axis of the unit cell. The Ag and Br atoms are disordered in the anion layer. The conducting layers contain uniform stacks of the translationally equivalent Pd(dddt) ₂ cations along the c-axis with a Pd ...Pd distance of 4.157(2) Å. Within the cation layers there are shortened interstack S ...S contacts (3.49(3) and 3.56(3) Å). The temperature dependence of the resistivity exhibits metallic behaviour down to 1.3 K. The resistivity anisotropy ( $\rho_a^*/\rho_{bc}$ ) at room temperature is about 600 and does not change considerably when decreasing the temperature down to 4.2 K. The origin of the metallic conductivity of [ Pd(dddt) ₂] Ag _1.54Br _3.50 as well as the stability of this salt with respect to metal-to-insulator transitions is explained on the basis of tight binding band structure calculations.

Stable Molecular Metal [ Pd(dddt) ] Ag Br : Synthesis, Crystal Structure, Transport Properties and Electronic Band Structure

Stable Molecular Metal [ Pd(dddt) $_{\bf 2}$ ] Ag $_{\bf 1.54}$ Br $_{\bf 3.50}$ : Synthesis, Crystal Structure, Transport Properties and Electronic Band Structure