Four probe electrical conductivity measurements from 15 to 300 K demonstrate that the mixed-valence compound Na3Cu4S4 is metallic. Measurements on single crystals reveal that the conductivity is highly anisotropic, with enhanced conductivity parallel to the crystal needle axis, corresponding to pseudo-one-dimensional [Cu4S41 23~]" columns in the structure. For single crystals, a» increases from 15000 IT1 cm"1 at 300 K to 300000 "1 cm"1 at 15 K. A small, temperature-independent magnetic susceptibility is consistent with metallic behavior. Diffuse-reflectance spectra support the formulation of this compound as a class 3B mixed-valence S2"/S" solid.

Four-probe electrical conductivity measurements from 15 to 300 K demonstrate that the mixedvalence compound K, Cu, S, is metallic at higher temperatures and below 160 K it forms lessconducting structural phases. The changes in conductivity in the range 16GlOO K are connected with changes in magnetic susceptibility. A rough estimate of the density of states at the Fermi level has been made.

Formation constants for 1 : 1 complexes of N,N-dialkylamides and N-acetylmorpholine with chloro-and nitrophenols have been determined spectrophotometrically in carbon tetrachloride solutions at 20 °C. Enthalpies of reaction for 14 systems have been obtained calorimetrically. Dipole moments of N,N-di(n-butyl)acetamide, N,N-di(isobutyl)acetamide and N-acetylmorpholine have been determined

Syntheses and properties of para-substituted benzoylpivaloylmethanes and their copper(II) chelates are described, i H n.m.r., u.v. and i.r. spectra of free ligands indicate a very high enol content. Molecular weight determinations showed that the bulky t-butyl and phenyl groups do not prevent association of chelates in chloroform solutions. All the chelates obey the Curie-Weiss law with the Weiss constant close to zero; magnetic moments lie within the 1.87-2.02 B.M. rangeover the 77 300Krange. l.r. and Raman spectra suggest that the complexes have a square planar stereochemistry and a trans geometrical structure.

l:lDioxane adducts of copper(ll) chelates with pata-sul~stituted benzoylpivaloylmethanes have been synthesized and their u.v., vis., i.r., mass, e.p.r, spectra as well as their magnetic moments and thermal stabilities investigated. Powdered samples of undiluted magnetically adducts were found to give well resolved e.p.r, spectra; the (S = 1) gll signal being split into nine lines. Magnetic susceptibilities measured down to 4 K did not reveal exchange interactions. The uncommon structure of the e.p.r, spectra is believed to be due to the dimeric structure of the adduct in which an interion dipolar zero-field splitting of the triplet state occurs. The Cu-Cu distance estimated from the e.p.r. Ddd parameter is found to be 7.4 A.