Reactions of bismuth in sulfur/iodine flux mixtures were explored at various temperatures and iodine concentrations. The observed products include Bi2S3, BiSI, and Bi13S18I2. The latter compound, formerly reported as “Bi19I3S27” grows as well formed needles from the flux. This enabled extensive crystallographic studies by single crystal XRD and powder synchrotron XRD. These data allow a more accurate assignment of the disordered bismuth sites in the structure, indicating formation of subvalent Bi2 4+ dimers; this results in a stoichiometry of Bi13S18I2. Thermal decomposition studies and Raman spectroscopy support this structural model, and electronic structure calculations and optical reflectance studies indicate this compound is an indirect band gap semiconductor with band gap of 0.3 eV.

Bismuth and antimony were reacted in sulfur/iodine flux mixtures at various temperatures and iodine concentrations to explore the effects of these variables on the synthesis and properties of BiSbSI products. The products grow as crystals; microprobe elemental analysis and UV/vis/NIR spectroscopy of the BiSbSI solid solutions indicate that substitution is homogeneous within individual crystals but varies up to 15% between crystals within each synthesis batch. Raman spectra show a two-mode behavior upon substitution, indicating covalent bonding within the structure, and TEM/SEM data confirm no presence of nanoclustering or segregation within the crystals.

183The main characteristics are: (i) Enediol anion species are involved in both isomerization and degradation reactions as shown by the formation of similar product mixtures upon alkaline degradation of various interconvertible monosaccharides. (ii) A fast equilibrium occurs between C, and C, saccharides, involving aldolization and retro-aldolization reactions, prior to the subsequent alkaline degradation reactions. (iii) Dicarbonyl compounds, the P-elimination products of enediol anion species, are key-intermediates which, via benzilic acid rearrangement, a-dicarbonyl cleavage and aldolization, lead to a variety of acid products. It may be noted that aldehydes formed by the a-dicarbonyl cleavage reaction will also be involved in aldolization reactions. The elongation of the carbon chain by aldolization of (di)carbonyls is terminated by benzilic acid rearrangement or a-dicarbonyl cleavage of oligomeric dicarbonyl intermediates. Abstract. Oxidation of 2-bromo-6-deuterio-4J-dirnethylphenol with Fremy's salt, followed by in situ reduction, yielded mainly 3-bromo-4,5-dimethylpyrocatecho1**, which affords evidence for a 1,3-bromine shift during the oxidation. The same treatment of 2-chloro-4,5-dimethylphenol yielded 4,5-dimethylpyrocatechol with a minor amount of 3-chloro-4,5-dimethylpyrocatechol. The 2-iodo compound gave 4,5-dimethylpyrocatechol as the only reaction product

Oxidation of the halogenophenol (I) with the title reagent followed by in situ reduction yields the rearranged product (II).