beta. -(BEDT-TTF)/sub 2/-AuCl/sub 4/: Importance of hydrogen--anion interactions in a descructive phase transition observed at low temperatures

Technical Report · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6417087

Geiser, U; Wang, Hau H; Anderson, B A; Williams, J M; Wangbo, Myung-Hwan

We report the synthesis of the first salt of the organic donor, bis-(ethylenedithio)tetrathiafulvalene (BEDT-TTF or simply ET), with a square-planar anion, AuCl/sub 4//sup /minus//, which leads to the 2:1 salt ..beta..-(ET)/sub 2/AuCl/sub 4/. The crystal structure analysis shows that the two-dimensional ET molecular network is comparable to that found in the ambient pressure superconductors ..beta..-(ET)/sub 2/X (X/sup /minus// = I/sub 3//sup /minus//, IBr/sub 2//sup /minus//, and AuI/sub 2//sup /minus//), with similar short interstack S/hor ellipsis/S contacts of /approximately/3.60 /angstrom/. During our attempt to obtain low temperature x-ray diffraction data we discovered a destructive phase transition upon prolongated cooling to 130 K. The transition originates from extremely short hydrogen/hor ellipsis/halogen contacts that occur when the conformation of an ethylene group of ET is frozen as the temperature is lowered. 21 refs., 5 figs., 5 tabs.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38; FG05-86ER45259
• OSTI ID: 6417087
• Report Number(s): ANL/PPRNT-89-136; ON: DE89008393
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
BOND ANGLE
BOND LENGTHS
CHEMICAL PREPARATION
CHLORIDES
CHLORINE COMPOUNDS
CRYSTAL STRUCTURE
DIMENSIONS
ELECTRONIC STRUCTURE
ELEMENTS
GOLD CHLORIDES
GOLD COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN
LATTICE PARAMETERS
LENGTH
NONMETALS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHASE TRANSFORMATIONS
SALTS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS