Bismuth subhalides

Bismuth-containing solid-state compounds pose an interest to both the physical inorganic chemists as well as condensed matter physicists due to the element's massive spin-orbit coupling, stabilization of lower oxidation states, and the inert pair effect.

[2][3] Topological insulators have caught attention of physical inorganic chemists as well as condensed matter physicists due to the unique physicochemical properties emerging upon transition from bulk to surface states.

The subject has been investigated by condensed matter physicists as well as mathematicians to provide a link between the experimental emerging properties and the modeled topology.

[1] Additionally, when bound to heavy halogens, bismuth subhalides give rise to a low-dimensional van der Waals bonded structure, exfoliatable into nanowires.

A series of such fundamental units align in the bulk material phase due to weak van der Waals interactions.

[6] Belonging to the larger class of quasi 1-dimensional van der Waals bonded materials, β-Bi4I4 has been recently reported as a novel topological insulator.

The mixture of solid-state precursors was sealed under dynamic vacuum in a quartz ampoule and subjected to a temperature gradient of 250 °C - 210 °C in a two-zone furnace for 20 days.

[2] Interestingly enough, the major contributors to the band structure around the Fermi level are bismuth's p orbitals of even and odd parity, thus giving the gerade and ungerade points of symmetry.

[11] The two lone pairs stemming from the rhodium metallic center are localized on the lowest-lying twicely degenerate set of molecular orbitals, consistent with the Möbius-type aromaticity.