Red needle-like crystals of the title compound were grown using a reaction between Bi metal and methyl iodide under solvothermal conditions. CH3BiI2 crystallizes in the monoclinic space group C2/m with an unusual one-dimensional organic−inorganic chain-like structure. The Bi atoms have a square pyramidal local geometry, with four I atoms forming the base and one methyl group occupying an apical site. Each basal square shares trans edges with two nearest neighbors to form a one-dimensional inorganic BiI2 chain along the b-axis. All methyl groups are covalently bonded to bismuth atoms and are aligned on one side of the BiI2 basal plane. The organic−inorganic chains are held together via van der Waals interaction, forming an extended solid state structural array. Extended Hückel band structure calculations demonstrate electronic one-dimensionality for CH3BiI2. Molecular modeling suggests that the square pyramidal Bi coordination arises primarily to reduce Bi−C antibonding character in the HOMO. The resulting Bi 6s and 6p hybridization in the valence band (HOMO) leads to a stereochemically active lone pair oriented trans to each methyl group. Thermal stability and decomposition of the title compound is examined using GC mass spectroscopy and simultaneous TGA and DTA techniques. CH3BiI2 begins to decompose at 185 °C in an inert atmosphere into methyl iodide and bismuth monoiodide, providing a new pathway to the formation of the interesting low valency one-dimensional conductor, BiI.

The intriguing bis(1,2,3,4-trithiazolium) dication (CNS3)2 2+ is a triplet state system, even in the solid state. Prompted by this molecule, we propose and theoretically study several hypothetical polymers, in the hope that they will display magnetic ordering. We seek systems in which the valence band is half-filled and as narrow as possible. In order to achieve that, we use as monomer units the members of a fascinating family of seven-π-electron, five-membered heterocycles which are closely related to (CNS3)2 2+. In these compounds, the highest two π orbitals are “distinct” from all the other orbitals. The uniqueness of these orbitals carries over in a systematic way into the extended systems (ortho- or meta-linked) which they form. Because the monomers have seven π electrons, the polymers have half-filled valence bands. We try to exploit the differences among the many possible heterocycles to provide polymers with narrow valence bands. Three such polymers, poly(cyclo-CSSSC+), poly(cyclo-CSSNC), and poly(cyclo-CSNSN+), are found to have valence bands approximately 0.3 eV wide; the first two are helical, and the third is planar.

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Die ternären Selenide K3FeSe3 und K3Fe2Se4 konnten über Schmelzreaktionen aus Kaliumcarbonat, Eisen und Selen in einem mit Selen beladenen Wasserstoffstrom bei 695 °C beziehungsweise bei 710–730 °C dargestellt werden. Röntgenographische Untersuchungen an Einkristallen führten zur Aufklärung der Kristallstrukturen. Die Atomanordnung der Verbindung K3FeSe3 ist durch [Fe2Se6]‐Doppeltetraeder charakterisiert, die durch die Kaliumionen isoliert werden (Raumgruppe P21/c, Z = 4). In der gemischtvalenten Verbindung K3Fe2Se4 bilden kantenverknüpfte durch Eisenatome zentrierte Selentetraeder Zick‐Zack‐Ketten, die wiederum durch Kaliumionen separiert werden (Raumgruppe Pnma, Z = 4).

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The electronic properties of polydithioquinone, a hypothetical C 4 S 2 carbon-sulfur polymer related to both tetrathiotetracene and thiothiophthene, are examined using approximate molecular orbital calculations. We focus on a curious pattern of sulfur-sulfur bonding interactions suggested by the band structure calculations, a pattern observed in thiothiophthenes and other molecular analogues of our polymer. The π system of each C 4 S 2 repeat unit contains eight electrons, consistent with a thiothiophthene-like rather than localized polydithioquinone valence structure. A pairing distortion in the carbon sublattice is implied; furthermore, the half-filled sulfur σ bands suggest that the sulfur sublattice is also likely to undergo distortions. Restricting our consideration to those distortions that retain planarity of the polymer, we find deformations of the carbon backbone considerably less favorable energetically than those of the sulfur sublattice. Four nicely bond-localized isomers result from the distortions of both carbon and sulfur sublattices; these all are found to be low bandgap semiconductors. We also examine helical distortions and find a stable isomer with an approximately 10-fold helical axis.