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In this paper, a detailed study and experimentation on acoustic-resonances (AR) in low-wattage metal-halide lamps is presented. In order to excite the AR without extinguishing the electric arc, the lamps were supplied by means of a dc current with a superposed variable-frequency ac signal. By using this methodology, theoretical and experimental resonances were compared in terms of frequency, amplitude, and threshold-power level for their excitation. The experiments were carried out on four 35-W samples from each manufacturer (Osram and Philips), each of them with burning times of 100, 2500, and 5000 h, in order to cope with the full life of this type of lamps. AR maps for each lamp were obtained. These maps show not only the frequencies at which AR appear but also the amplitude of the resonances. The obtained AR maps are intended to be used by designers in order to know if a particular instantaneous lamp power waveform would be suitable to supply the lamp without generating AR. An application example on how to use these maps is also presented. Index Terms--Acoustic-resonance (AR) characterization, AR maps, electronic ballast, high frequency, metal-halide (MH) lamp, power harmonics.

The reaction of the metal halide with the sterically demanding ligand (i-[Pr.sub.2][C.sub.6][H.sub.3]N)(C(Me)[(N[C.sub.6] [H.sub.3]-i-[Pr.sub.2])).sub.2] afforded the complexes (i-[Pr.sub.2] [C.sub.6][H.sub.3]N)(C(Me)[(N[C.sub.6][H.sub.3]-i-[Pr.sub.2])).sub.2] M[X.sub.2] (X = C1, M = Fe (2), Co (3); X = Br, M = Ni (4), M = Cu (5), Zn (e)). The species of 2 reacts with Li(O[Et.sub.2])B ([C.sub.6][F.sub.5])4 to form the yellow adeuct [(i-[Pr.sub.2] [C.sub.6][H.sub.3]N)(C(Me)[(N[C.sub.6][H.sub.3]i-[Pr.sub.2])).sub.2] Fe[([micro]-C1).sub.2]Li[(O[Et.sub.2]).sub.2]][B[([C.sub.6][F.s (7) while alkylation of 2 gave (i-[Pr.sub.2][C.sub.6][H.sub.3]N)(C(Me) [(N[C.sub.6][H.sub.3]-i-[Pr.sub.2])).sub.2]FeC1C[H.sub.2]Si[Me.sub.3] (8). The species [(i-[Pr.sub.2][C.sub.6][H.sub.3]N)(C(Me)[(N[C.sub.6] [H.sub.3]-i-[Pr.sub.2])).sub.2]Ni([[eta].sup.3]-[C.sub.3][H.sub.5])] ([B(3,5-C[F.sub.3][C.sub.6][H.sub.3]).sub.4]] (9) was obtained from reaction of 1 with [[([[eta].sup.3]-[C.sub.3][H.sub.5])NiBr].sub.2] and [Na][B(3,5-[(C[F.sub.3]).sub.2][C.sub.6][H.sub.3]).sub.4]] while reaction of 4 with Super-Hydride afforded (i-[Pr.sub.2][C.sub.6] [H.sub.3]N)-(C(Me)[(N[C.sub.6][H.sub.3]-i-[Pr.sub.2])).sub.2]Ni[H. (10). X-ray data are reported for 2-10. The sterically demanding nature of the ligand inhibits subsequent reactivity of these species. Key words: sterically demanding ligands, chelate complexes, X-ray structure, diimine ligands. Resume : La reaction d'un halogenure metallique avec le ligand steriquement encombre (i-[Pr.sub.2][C.sub.6][H.sub.3]N)(C(Me) [(N[C.sub.6][H.sub.3]-i-[Pr.sub.2])).sub.2] conduit a la formation des complexes (i-[Pr.sub.2][C.sub.6][H.sub.3]N)(C(Me)[(N[C.sub.6] [H.sub.3]-i-[Pr.sub.2])).sub.2]M[X.sub.2] (X = Cl, M = Fe (2), Co (3); X = Br, M = Ni (4), M = Cu (5), Zn (e)). L'espece 2 reagit avec le Li(O[Et.sub.2])B[([C.sub.6][F.sub.5]).sub.4] pour former l'adeuit jaune [(i-[Pr.sub.2][C.sub.6][H.sub.3]N)[(C(Me)(N[C.sub.6] [H.sub.3]-i-[Pr.sub.2])).sub.2]Fe[([micro]-C1).sub.2]Li[(O[E.sub.2]) (7) alors que l'alkylation du compose 2 conduit h la formation du complexe (i-[Pr.sub.2][C.sub.6][H.sub.3]N)(C(Me) [(N[C.sub.6][H.sub.3]-i-[Pr.sub.2])).sub.2]FeC1C[H.sub.2]Si[Me.sub.3] (8). On a obtenu l'espece (i-Prz[C.sub.6][H.sub.3]N)-(C(Me)[(N[C.sub.6] [H.sub.3]-i-[Pr.sub.2])).sub.2]Ni([[eta].sup.3]-[C.su (9) par redaction du compose 1 avec le [[([[eta].sup.3]-[C.sub.3][H.sub.5])NiBr].sub.2] et le [Na][[B(3,5-[(C[F.sub.3]).sub.2][C.sub.6][H.sub.3]).sub.4]] alors que la redaction du compose 4 avec le Super-Hydrure conduit a la formation du (i-[Pr.sub.2][C.sub.6][H.sub.3]N)[(C(Me)(N[C.sub.6] [H.sub.3]-i-Prz)).sub.2]Ni[H.sub.2]B[Et.sub.2] (10). On rapporte les donnees de diffraction des rayons X par les composes 2-10. L'encombrement sterique du ligand inhibe toute reactivite subsdquente de ces especes. Mots cles : ligands steriquement encombres, complexes de chelates, structure par diffraction des rayons X, diimine ligands. [Traduit par la Redaction]

The mass spectrometric identification of dimeric species in the SnBr2-SnI2 system is presented. The discussion on the implications of the thermodynamic and structural data obtained by theoretical methods on the observed fragmentation paths of the neutral Sn2BrxI(sub 4-x) species are presented.

The investigation of the electronic structure and molecular properties of doubly charge transition metal helides is presented. Basic sets are developed for the first row transition metals for this purpose.

Treatment of gold(I) halide complexes of the type L-Au-X [where L = P[Ph.sub.3], P[Et.sub.3] with X = Cl, Br, I, or L = 2,6-[(MeO).sub.2][C.sub.6][H.sub.3]P[Ph.sub.2] with X = CI] with AgSb[F.sub.6] in the molar ratio 2:1 in dichloromethane/tetrahydrofuran at -78 [degrees] C affords high yields of di[gold(I)]halonium salts of the formula {X[[Au(P[R.sub.3])].sub.2]]+ Sb[F.sup.-.sub.6] (2-8). A determination of the crystal structures of the four triarylphosphine complexes (2-4, 8) revealed the presence of novel tetranuclear dications with a highly symmetrical structure (point group [S.sub.4]) that arises from self-assembly of the dinuclear monocations through a set of four equivalent aurophilic Au-Au interactions. A comparison with two reference structures of corresponding chloronium perchlorate and bromonium tetrafluoroborate salts with monomeric, dinuclear cations shows that the geometry of the latter is greatly altered on dimerization to optimize the interactions between the closed-shell metal centers (Au: [5d.sup.10]). Weak metallophilic bonding clearly becomes significant only in crystal lattices where anions with a larger ionic radius (Sb[F.sup.-.sub.6] vs. B[F.sup.-.sub.4], Cl[O.sub.4]) reduce the otherwise dominant role of strong interionic Coulomb forces. The results indicate that aurophilic bonding is indeed an ubiquitous, quite dependable mode of intermetallic interactions provided that the right environment is chosen to allow the weak forces to become operative.

An approach developed for teaching descriptive inorganic chemistry courses involves presenting a limited set of facts about several elements or several compounds. The facts are not memorized, but used as jumping-off points for inquiry into whys and wherefores of the chemistry of the elements. Stoichiometries of known, stable binary compounds is a fundamental aspect of descriptive chemistry, but it is not interesting to memorize a list of chemical formulas when d-metals compound stochiometry is studied.

Research describes Sonogashira coupling involving aryl halides or pseudohalides and pyridine and thiophene derivatives under homogeneous reaction conditions using microwave heating. Results indicate that the method is rapid and good yields are obtined within a few minutes.

Research into the molecular structure of metal halides is presented. Metal halide structural chemistry has many of the diverse features of inorganic chemistry.

An investigation into the interaction of CF3CfCl2 with gamma-Al2O3 uses a combination of FTIR spectroscopic research and reaction kinetics experiments. Details of the study are discussed.

An investigation is presented into the theory that Na6CdCl8 can exist only as precipitates in a surrounding NaCl matrix. The structure and properties of NACl and the Suzuki phase of Na6CdCl8 is presented.

The use of fluorimetric and diffuse reflectance measurements on the isomorphous series alpha-CuAlBrxCl4-x ( x = 0-4) to investigate the electronic structure of CuAlCl4 is described. Alpha- and beta-CuAlCl4 phases demonstrate luminescence of brilliant blue to blue-green.

The decomposition of metal iodides into metal and iodine atoms in metal arc discharges for the ScI3/NaI/Hg, DyI3/Hg, CsI/Hg and T1I/NaI/Hg systems was studied between the temperature range 1000 to 3000 K. The study seeks to relate the distribution of metal vapors in metal halide systems of iodides to the Gibb's energy change. Results indicate that the vapor density distribution agree with that experimentally calculated for CsI, T1I and DyI3. For the ScI3-NaI system, the calculated values are larger than the experimental ones.

The synthesis of a new compound which is a nominal polymorph of the novel tetragonal (alpha-)K4-La6I14Os, in which undistorted octahedral La6(Os)I(super i)(sub 10) units are interbridged by I(super i-a)(sub 4/2) into a new planar network, is reported. The synthesis emphasizes the possibility of new structures that can be produced by subtle variations in such quaternary systems.

The compounds (Cu3Cl3(bipypy)), (CuBr(bipypy))2, (Cu2Br2(bipypy)) and (Cu3(CN)3(bipypy)) were prepared from mixtures of the copper halide salts and the ligand bis-2,3-(2-pyridyl)pyrazine (bipypy) in hydrothermal media. The utilization of the bipypy molecule as a potential bridging ligand permitted the preparation of a series of new copper halides and pseudo-halide compounds. Not only were novel one- and two-dimensional solid-state inorganic-organic composite phases were synthesized and structurally characterized but a unique neutral molecular dimer was observed.

A study on lithium halides in water was conducted to carry out a simple comparison of the extremes of the liquid state for two common lithium salt systems where concentrated solutions approaching the dihydrate could be investigated in both molten and supercooled states. The experimental results suggest the types of systems where higher boiling points might be obtained without undue increase on the glass transition temperature and, therefore, the viscosity.

The full lithium substitution in gallosilicate and aluminogermanate halide sodalites was described along with the characterization by Rietveld analysis of powder neutron diffraction data. The resultant parameters derived from the Rietveld analysis indicated that contraction of the unit cell was principally accommodated by a decrease in the T-O-T framework bond angle and an increase in the tetrahedral tilt angles. Aluminogermanate chloride sodalite appeared more susceptible to destruction upon lithium exchange, as shown by the need to shorten the sodalite/nitrate contact time.

A model is derived to determine the absolute value of the solid-liquid interfacial energy to pure spherical and polyhedral particles. The model is based on the fundamental theory of intrinsic specific interfacial energy of a solid-liquid interface without adsorption obtained in an earlier study. Comparison of model results with those from experiments involving silver halide sols also showed good agreement.

The molecular structure of aluminum trihalides AlX3 (X = Cl, Br, I) was determined using gas-phase electron-diffraction data and the results of ab initio molecular orbital and normal coordinate computations. The structure of the chloride and bromide dimers Al2Cl6 and Al2Br6 was also determined. The vibrational force fields of all compounds were then examined, with theoretical and empirical results being compared and discussed.

Ambient temperature AlCl3-ImCl (1-ethyl-3-methylimidazolium chloride) molten salts were observed to allow the systematic study of redox behavior of centered hexanuclear zirconium halide clusters in solution. The cyclic voltammetric data gathered showed a correlation between the oxidation potentials and the cluster charge. The stabilities of cluster species obtained through electrochemical oxidation were generally in agreement with scattered observations from preparative studies.

The 1:1 and 2:1 reactions of (Me(sub 3)Si)(sub 2)PLi*2THF with several amino chlorophosphanes were investigated. Both reactant stoichiometries produce the four-membered ring compound (super i)Pr(sub 2)NP(Me(sub 3)Si)P((super i)Pr(sub 2)NP(Me(sub 3)Si)P via different reaction schemes. The four-membered ring compound combines with Fe(sub 2)(CO)(sub 9) to yield a monometallic complex (super i)Pr(sub 2)NP(Me(sub 3)Si)P(super i)Pr(sub 2)N)P(Me(sub 3)Si)P*Fe(CO)(sub 4) in which the Fe(CO)(sub 4) fragment is bonded to one of the Me(sub 3)SiP centers.

An experiment reports a novel crystal-engineering design strategy to imbed practically unlimited numbers of porphyrin chromophores in desirable, controlled metalation states into highly organizable, rigid, one-dimensional and/or two-dimensional crystalline, supramolecular arrays. The approach enables a virtually limitless number of metal ions to be inserted into the polymeric porphyrin arrays and is therefore relevant to the design of light harvesting model systems.

Research was conducted to examine the molecular geometries, vibrational frequencies and bond dissociation energies of cerium tri- and tetrahalides CeX3 and CeX4 using relativistic effective core potential quantum chemical investigations. All calculations were carried out using the HONDO95.3 code on IBM-SP and Cray C90 computers. Results indicate that pyramidal structures are found for CeF3 for any of 4f1 state at all levels of theory.

The reaction of high- and low-spin cobalt(II) compounds with alkyl halides and the structure of the resulting five-coordinate cobalt(III) complexes were investigated. In addition, one-electron transformations of paramagnetic cobalt compounds were examined. Results showed that one-electron oxidation of cobalt(II) and cobalt(III) by certain alkyl halides depends on both the spin state of the compound and the ancillary ligands. It was also found that the five-coordinate cobalt(III) alkyl halide complexes are unstable.

Homoleptic, d0 early transition metal acetylide derivatives were synthesized using the extremely bulky tBu3SiC equivalent to C- ligand. The SitBu3 group was utilized to circumvent synthetic difficulties in preparing the derivatives. Structural characterizations showed a distorted trigonal prismatic configuration for (tBu3SiC equivalent to C)6Ta(super -) and an octahedral geometry for (tBu3SiC equivalent to C)6M(super 2-) (M = Zr, Hf). The distortion in the case of tantalum was caused by steric interactions of the tBu3Si groups.

Experiments were performed to investigate the reaction of the methyl halides, CH3F, CH3Cl, CH3Br and CH3I with excitable magnesium atoms induced by laser ablation. The higher kinetic and electronic energy of the laser-ablated magnesium atoms allowed the examination of the methyl fluoride, the least reactive alkyl halide in the Grignard species. The findings identified the secondary reaction products which were produced by isotopic substitution.

Research was conducted to investigate the reduction of WCl6 with Hg, Sb, bi or combinations of Sb or Bi with an alkali metal chloride. Another objective was to demonstrate approaches for four new, convenient, high-yield routes to (H3O)2-(W6(mu-3-Cl)8Cl6)(OH2)x and W6Cl12. All the reductions can be performed in borosilicate glass ampules and do not require particular care in temperature control and gradients or use of highly purified WCl6.

An automated particle analysis routine is implemented on an electron microprobe for analyzing the chemical composition and projective area of populations of individual silver halide microcrystals. An LN2 cryostage is used to prevent material degradation due to reaction with the impinging electron beam. The background in the EDX spectra is lowered by depositing the microcrystals on a carbon-coated copper grid, mounted in a transmission holder. The IL[Alpha]/AgL[Alpha] net X-ray intensity ratio, obtained from a spectrum-fitting algorithm, is used to determine the crystal composition by means of a standard-based calibration curve. The uncertainty on the concentration measurement of individual microcrystals is calculated using the uncertainties on the net X-ray counts and the uncertainties on the calibration curve. The area measurement is optimized by introducing a gray value histogram correction on each individual measurement. Overlapping microcrystals are scrapped from the analysis by defining a maximum shape factor, against which the shape factor of the microcrystal is tested. To minimize problems with drift of the cryostage, spectrum acquisition is carried out immediately after a single microcrystal has been located, based on the backscattered electron image. Several applications are discussed.

Density functional calculations were used to model trends in redox potentials for isovalent series of 5d hexafluoro- and -chlorometalates, (MX6)(super 0/-) and (MX6)(super -/2-). Results showed the same trends seen in the experimental data, particularly the pronounced convergence of the electrochemical redox potentials for the (MF6)(super z/z-1) and (MCl6)(super z/z-1) series and the nonlinear zigzag progression. The latter is explained by the increase in metal core charge and the octahedral symmetry of the species.

Tube furnace reduction of WCl6 with mercury, bismuth or antimony represents three new easy and convenient approaches for the efficient preparation of crystalline ((WCl4)x). The easiest and highest-yield methods for the preparation of (WCl4)x were the solid-state reduction of WCl6 with antimony and reduction of WCl6 with tin in dichloroethane. The molecular structure of (WCl4)x is comprised of chains of a linear polymer of opposite-edge-sharing bioctahedra with alternating short and long W***W distances.

Research was conducted to investigate titanium and zirconium alkyl silyl complexes (Me3ECH2)3M-SiR3 (M = Ti, Zr, E = C, Si), which were prepared through the reactions of trialkyl chloride complexes (Me3ECH2)3MCl. New trialkyl halide complexes were prepared and characterized. The crystal structure of (Me3CCH2)3ZrCl with unusual linear and symmetric polymeric -Zr-Cl-Zr-Cl- chains are also presented.

Research was conducted to examine the hypothesis that copper aluminum halides will yield a family of Cu(sub m)Al(sub m)Cl(sub 4m) frameworks, analogous to the known family of aluminophosphates. The synthesis and characterization of beta-CuAlCl4 and the small-molecule gas sorption properties are presented. Results indicate that the structures of both alpha- and beta-CuAlCl4 reveal large van der Waals channels which are proposed to be important for the reversible adsorption of carbon monoxide and ethylene by these materials.

The compounds CsNaLa6Br14N2 and La3Br6N were obtained in high yields as pale yellow, transparent crystals after reacting with appropriate mixtures of CsBr, NaBr, LaBr3 and LaN in sealed Ta tubing at 850 deg C for 20 d. The significant structural characteristics of both compounds were pairs of rare-earth-metal tetrahedra that were each centered by N and share a common edge to form La6N2 bitetrahedral units.

Research was conducted to examine the interaction of indium(I) halides with bifunctional arylmercury derivatives and to show that the reaction of peri-dimercurated naphthalene compounds with indium(I) halides leads to the synthesis of novel indium-containing ring systems. Results suggest that the course of the reaction of polyfunctional organomercuric compounds with indium(I) halides is difficult to predict but permits the synthesis of novel systems.

A new procedure based on scanning ion microprobe mass analysis (SIMS) is developed to characterize populations of silver halide microcrystals present in a photographic emulsion with emphasis on the thickness distribution of the surface layers usually found on these microcrystals in the 5-30 nm range. Using a Cameca IMS-4f instrument one is able to image the lateral and in-depth distributions of the halides in individual microcrystals. A digital image processing system interfaced with the SIMS instrument permits the acquisition of spatially resolved mass-selected data (ion images) for a number of single microcrystals. Small regions ([approximately]300 nm in diameter) within each crystal are selected a posteriori for local area 'retro' depth profiling by computer reconstruction. By averaging the gray values measured in suitable parts of the crystal, the thickness of the surface layers can be determined, allowing one to make a three-dimensional reconstruction of the chemical composition of the microcrystals. Using this methodology, the characteristics (thickness and chemical composition) of surface and subsurface layers of different samples can be compared and subclasses in one population can be detected. With the aid of home-developed hardware and software, the image acquisition procedure was automated, making it possible to automatically measure a sufficiently large number of microcrystals. In this way the analysis time was decreased and the statistical relevance of the data improved. Two examples are given which illustrate the power and practical use of the developed methodology.

A quantitative model has been developed for decay and formation kinetics of light-induced dye radicals on spectrally sensitized silver bormide (AgBr) microcrystals measured by electron spin resonance (ESR) spectroscopy. It makes prediction of decay of the oxidized dye molecules using fitting parameters of formation curves possible. Dhye positive holes are detected using ESR spectrosopy. For the dyts studied, radicals are oxidized dye molecules on the surface of spectrally sensitized AgBr microcrystals.

Chemical research has established a method of creating the novel lithium amide LiN(SiMe2CH2NMe2)2 using NH3, silylamine Me2NSiMe2CH2NMe2 and butyllithium. The lithium amide dimer reacts with a series of group four starting halides, MCL4, to produce the complexes MCl3[N(SiMe2CH2NMe2)2]. Each trihalide structure is described.

A method of producing the p-functionalized metallacyclophosphazenes [(Me2N)2PN]2VCl2, [(Me2N)2PN]2MoCl3.MeCN and [(Me2N)2PN]2WCL3.MeCN is described which uses the reaction of Cl3VNSiMe3 with the metal nitride halides CL3MoN and Cl3-WN with [(Me2N)2PNH2}2N]+Cl- is described. The electronic structure of CF3-substituted rings are discussed.

A study was conducted on the synthesis and properties of the complexes of 1,1',5,5'-tetramethyl-6,6'-dioxobis(verdazyl) (BVD) with copper halides. The findings indicate that the reaction leads to the formation of a new series of coordination polymers. Moreover, the interaction may be tuned by consideration of the copper auxiliary ligands. The bridging ability of the BVD ligand may also play an important role in the development of new magnetic systems.

The trihalocuprate(I) compounds resulting from the reaction of thiuram sulfides, also known as bis(N,N'-dimethylthiocarbamoyl) sulfides with copper(II) halides were studied structurally using infrared spectroscopy. All the complexes were found to have the basic S2CuX units and the molecular structure of each was found to be unique, depending on the relative basicity of the S and halogen potential bridging atoms.

It is shown, to our knowledge for the first time, that commercially available silver halide film emulsions may be used to record infrared radiation (10.6 [[micro]meter]) without the use of visible light as the coactivator. We present a film characterization study. Key words: Infrared, photographic film.

The W2 core structures in W2(mu-H)(mu-O2CC6H5)Br4(mu-dppm)2.2THF and W2(mu-H)(mu-O2CC6H5)Cl4(mu-dppm)2 are identical. The bond distance of the bromide complex is 2.535(2) and that of the chloride is 2.554(2) angstroms. The tungsten-halide bond distances in the bromide are larger than the chloride complexes. Both the compounds contain two types of tungsten-halide bond distances and angles. The bonding nature in ditungsten halide compounds and NMR spectroscopic characterization are discussed.

The influence of the beam ratio between reference and object beam intensities on the characteristics of diffuse-object holograms recorded as volume phase holograms in bleached silver halide emulsion is experimentally analyzed. Measurements of the diffraction efficiency and the signal-to-noise ratio of the holograms are taken. The experimental results presented show that when the beam ratio increases, the diffraction efficiency decreases and the signal-to-noise ratio increases; these two holographic parameters behave in this way no matter what type of processing is used. Key words: Holographic recording materials, silver halide emulsions, diffuse-object holograms.

Optical absorption and emission data for octahedral clusters of Mo6-based metal complexes which use Cl-, Br-, I- for outer ligand substitutions were compared. The density functional treatment approach was used to determine the electronic structure and properties of the systems. The hypothetical 4,4'-bipyridine linked dimer was also used to analyze the synthesis of the low-dimensional linked-cluster compounds.

New low dimensional layered organic-inorganic structural units are formed when crystal growth of (NH2C{I}=NH2)3MI5 (M = Sn, Pb) occurs in an aqueous solution. The resulting single (110)-oriented perovskite sheets resemble the (NH2C{I}=NH2)2(CH3NH3)mSn(sub m)I (sub 3m+2) series. Tin and lead atoms are situated in an irregular iodine octahedral environment and their lone electron pairs, which are more active in tin than in lead, are stereochemically active. The iodoformamidinium cations stabilize the crystal structure.

The electrochemical reactions of the nickel(II) tris(2-diphenylphosphinoethyl)phosphine (P3P') halide cations in acetonitrile and dichloromethane were investigated. It was found that the cations reduce to the nickel(0) Ni eta(sup 4)-P3P' X (sup -) species. The bromo and iodo complexes lose halides and form a P3P'-bridged nickel(0) dimer after reduction. All, however, are 'irreversibly oxidized to the analogous nickel(III) series.'

The synthesis, molecular structure and characteristics of two- and three-dimensional copper halide complexes with (tetrakis(methylthio)tetrathiafulvalene) (TMT-TTF) are described. The copper(I) complexes, which were studied via single crystal x-ray diffraction techniques, were Cu2(mu-X)2(mu-TMT-TTF) infinity where (X = Cl,Br,I). When X = Cl, the result is a '2D sheet of TMT-TTF molecules arranged between zigzag frames of CuCl.

Several phosphatovanadium cluster compounds with embedded halide ions were investigated. They include the chloride (VO)6(O3POSiMe3)8Cl and the fluoride Et4P (sup +) (V2O3)2(O3PPh)4F (sup -) and the methylphosphato and butyl phosphato analogues of the fluoride compound. Both enable the oxidation of 1,4-cyclohexadiene to benzene in hot pyridine mixture. In addition, both have only three oxygen atoms per phosphorus for cluster bonding, thus allowing the phosphorus centers to serve as sites of positive Gaussian curvature.