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The electronic structures of binary M21S8 (M = Nb, Zr) and isostructural ternary (M,M')(sub 21)S8 (M,M' = Hf, Ti; Nb, Ta) phases are analyzed by means of extended Huckel tight-binding band structure calculations. The distribution of hafnium and titanium atoms on the six crystallographically independent metal sites in the ternary phase Hf(sub 7.5)Ti(sub 13.5) are rationalized using metal-metal bond strength, electronegatavity/charge, and site volume arguments.

The addition of alkali or silver salts of dicyananoamide (dca), tricyanomethanide (tcm) and tetracyanoborate (tcb) to a solution of B[([C.sub.6][F.sub.5]).sub.3] in diethyl ether has produced salts containing voluminous C[([C.sub.6][F.sub.5]).sub.3] adduct anions. The studies have shown that as counterions for cationic early transition metal catalysts, the anions have displayed reduced ion pairing and hence increased catalytic activity.

The synthesis and structural determination of the first zirconium cluster compound with acetonitrile ligands, which has all the necessary properties for a widely usable starting material for new cluster phases, are described. The advantage of both title phases is that they contain Lewis acidic zirconium cluster units, which are useful as catalysts, with the additional advantage of tuneable redox properties.

The excision of chloride based Zr cluster units from solid-state start materials, their transformation to bromides by using EMIm-Br/Al[Br.sub.3] ionic liquids, the crystal structures of [(EMIm).sub.4][([Zr.sub.6]Z)[Br.sub.18]] (Z = Be, Fe) and spectroscopic data of the iron centered phase in different ionic liquids are reported. The results have concluded that this complete ligand exchange is considered as reversible, with the equilibrium being largely determined by the free ligand concentration.

The straightforward preparation and the crystal structure of the new compound [[Nb.sub.6][Cl.sup.i.sub.12][(CH3OH).sup.a.sub.4][Cl.sup.a.sub.2]].6C[H.sub.3]OH which contains the neutral [N[b.sub.6]C[l.sup.i.sub.12][(C[H.sub.3]OH).sup.a.sub.4]C[l.sup.a.sub.2]] cluster unit with an octahedral [[N[b.sub.6]C[l.sup.i.sub.12].sup.2+] cluster core is reported. The three-dimensional arrangement of the cluster units follows a stacking along the unit cell directions, resulting in a layered arrangement of the clusters, between which the methanol molecules are located.

Research has been conducted on dimeric rhodium(I) bis(carbonyl) chloride. The reaction of this compound with Lewis acids carried out in CO atmosphere at room temperature has led to salts which have been characterized by Raman spectroscopy and single-crystal X-ray diffraction.

The research of mixed-halide zicronium systems is presented. It is found that inter cluster-bridging halide positions are occupied by one halide type.

One-pot three-component reactions of secondary or primary phosphines and primary amines with glyoxylic acid provide a wide variety of acyclic or cyclic phosphinoglycines, in the case of some chiral amines with high diastereoselectivity. The structure, hydrolysis, oxidation, coordination at M(CO)5 (M = Cr, Mo, W), and use in nickel-catalyzed ethylene oligomerization were studied. [ABSTRACT FROM AUTHOR]

Describes a mixed-halide structure with zigzag chains of clusters in multiply twinned crystals. Zigzag chains of boron-centered octahedra; Description of the noncluster interconnecting two-bonded X[sup i] sites; Appearance of crystals.

Investigates the structures of reduced rare-earth metal halides. Analysis of structural differences in isoelectric compounds; Establishment of the La[sub 3]I[sub 3]Ru structure by single-crystal X-ray diffraction; Dependence of structural variation halides on differences in orbital energies between corresponding rare-earth metal.

Reports on an extended Huckle tight-binding band structure study of the bonding in binary and isostructural ternary phases to understand the metal site occupation. Computational details; Electronic structure of the M[sub 12]S[sub 8] phases; Site occupation problem in the (M,M')[sub 21]S[sub 8] phases.

Reports the synthesis of phase pure samples of niobium Nb21-sulfur (S)8. Experimental section; Discussion on the results.

Presents information on an investigation to determine the effect of halogen size and structure stability. Information on experimental section; Details on crystal structure studies; Discussions on results; Details on matrix effects.

Presents a study focusing on the structure type of a family of reduced zirconium halides as it relates to inorganic chemistry. Description of methods used in the study; Stability of certain structure types; Details on results; Influence of iode and chloride ligands.