New ambient pressure organic superconductors:. alpha. -(BEDT-TTF) sub 2 (NH sub 4 )Hg(SCN) sub 4 ,. beta. m-(BEDO-TTF) sub 3 Cu sub 2 (NCS) sub 3 , and. kappa. -(BEDT-TTF) sub 2 Cu(N(CN) sub 2 )Br

Conference · Mon Jan 01 04:00:00 EST 1990

OSTI ID:6298754

Wang, H H; Beno, M A; Carlson, K D; Geiser, U; Kini, A M; Montgomery, L K; Thompson, J E; Williams, J M

More than one hundred and twenty conducting salts based on the organic donor-molecule BEDT-TTF are known, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene (abbreviated herein as ET). Several of the early salts possessed tetrahedral and octahedral anions, such as (ET){sub 2}ClO{sub 4}(TCE), (ET){sub 2}PF{sub 6}, (ET){sub 2}ReO{sub 4}, and (ET){sub 2}BrO{sub 4}. The perchlorate salt is metallic to 1.4 K,{sup 1} and the perrenate derivative was the first ET based organic superconductor ({Tc} 2 K, 4.5 kbar). Since the discovery of ambient pressure superconductivity in {beta}-(ET){sub 2}I{sub 3} ({Tc} 1.4 K),{sup 5} other isostructural {beta}-(ET){sub 2}X salts have been prepared with higher {Tc}'s. A structure-property correlation for the {beta}-type salts has been reviewed in this volume; it predicts that {Tc}'s higher than 8K are possible if {beta}-salts with linear anions longer than I{sub 3}{sup {minus}} can be synthesized. During the search for new linear anions, a variety of compounds with discovered with polymeric anions. The report of superconductivity in {kappa}-(ET){sub 4}Hg{sub 3}X{sub 8} (X = Cl, {Tc} 5.4 K 29 kbar and X = Br, {Tc} 4.3 K ambient pressure and 6.7 K 3.5 kbar) and {kappa}-(ET){sub 2}Cu(NCS){sub 2} ({Tc} 10.4 K) further stimulated the search for novel polymeric anions. A general synthetic strategy for preparing new salts containing polymeric anions is to couple a coordinatively unsaturated neutral transition metal halide/pseudohalide with a simple halide or pseudohalide during an electrocrystallization synthesis. In this article, the authors discuss three new ambient pressure organic superconductors with novel polymeric anions, {alpha}-(ET){sub 2}(NH{sub 4})Hg(SCN){sub 4}, {beta}m-(BO){sub 3}Cu{sub 2}(NCS){sub 3} and {kappa}-(ET){sub 2}Cu(N(CN){sub 2})Br. 48 refs., 8 figs., 2 tabs.

• Research Organization: Argonne National Lab., IL (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6298754
• Report Number(s): CONF-900528-6; ON: DE91006004
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMMONIA
ANIONS
ANTITHYROID DRUGS
BEDT-TTF
CARBONIC ACID DERIVATIVES
CHARGED PARTICLES
COMPLEXES
CRYSTAL GROWTH
CRYSTALLIZATION
DRUGS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HETEROCYCLIC COMPOUNDS
HORMONE ANTAGONISTS
HYDRIDES
HYDROGEN COMPOUNDS
IONS
LIGANDS
MERCURY COMPLEXES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANIC SUPERCONDUCTORS
ORGANOMETALLIC COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POLYMERS
SALTS
SILVER COMPLEXES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
THIOCYANATES
TRANSITION ELEMENT COMPLEXES
TRANSITION TEMPERATURE