New electrically conducting solids based on nickel(II) - bis (1,3-dithiole-2-thione-4,5-diselenolate)

Conference · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5371566

Kini, A M; Beno, M A; Budz, S; Wang, H H; Williams, J M

Electrochemical oxidation of the metal-organic complex, nickel(II) - bis(1,3 - dithiole - 2 - thione - 4,5 - diselenolate) (Ni(dsit){sub 2}){sup 2{minus}}, yields highly conducting salts, in which the stoichiometry and packing arrangement depends critically on the site of the counter-cations incorporated. Smaller counter-cations, e.g., tetramethylammonium and tetramethylphosphonium ions, yield salts with a 1:2 cation N:(dsit){sub 2} stoichiometry, while the larger tetraethylammonium ion yields a salt with 2:2 stoichiometry. In both these salts, the Ni(dsit){sub 2} units occur as tightly bound dimers, in which coordination geometry of nickel is a unique, but not unprecedented square-pyramidal type. Moreover, the packing arrangement of (Ni(dsit){sub 2}){sub 2} dimer units in both (Me{sub 4}N) (Ni(dsit){sub 2}){sub 2} and (Me{sub 4}P) (Ni(dsit){sub 2}){sub 2} is {kappa}-type, similar to that found in the organic superconductor with the highest-known T{sub c} (10.4 K), {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2}. Both these salts possess good room temperature conductivities ({sigma}{sub rt} = 36 and 19 S {center dot} cm{sup {minus}1} respectively), but the temperature dependence of their conductivities is characteristic of semiconductors with small bandgaps (E{sub g} = 0.11 and 0.13 eV respectively). The 2:2 salt (Et{sub 4}N){sub 2}(Ni(dsit){sub 2}){sub 2}, on the other hand, has a substantially lower room temperature conductivity, about six orders of magnitude smaller than that of the 1:2 salts. 19 refs., 3 figs., 3 tabs.

• Research Organization: Argonne National Lab., IL (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5371566
• Report Number(s): CONF-891119-30; ON: DE90003788
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CHEMICAL REACTIONS
COMPLEXES
CRYSTAL STRUCTURE
DIMERS
ELECTRICAL PROPERTIES
NICKEL COMPLEXES
OXIDATION
PHYSICAL PROPERTIES
SALTS
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPLEXES