Boron triiodide

Preparation

Boron triiodide can be prepared by the reaction of boron with iodine at 209.5 °C or 409.1 °F. It can also be prepared by reacting hydroiodic acid with boron trichloride:

: (reaction requires high temperature)

Another method is by reacting lithium borohydride with iodine. As well as boron triiodide, this reaction also produces lithium iodide, hydrogen and hydrogen iodide:

:

Properties

In its pure state, boron triiodide forms colorless, otherwise reddish, shiny, air and hydrolysis-sensitive crystals, which have a hexagonal crystal structure (a = 699.09 ± 0.02 pm, c = 736.42 ± 0.03 pm, space group P63*/m* (space group no. 176)). Boron triiodide is a strong Lewis acid and soluble in carbon disulfide.

Boron triiodide reacts with water and decomposes to boric acid and hydriodic acid:

:

Its dielectric constant is 5.38 and its heat of vaporization is 40.5 kJ/mol. At extremely high pressures, BI3 becomes metallic at ~23 GPa and is a superconductor above ~27 GPa.

Applications

Boron triiodide can be used to produce other chemical compounds and as a catalyst (for example in coal liquefaction).

References

References

1. {{RubberBible86th
2. (1978). "Handbuch der präparativen anorganischen Chemie. 2". Enke.
3. "Beiträge zur Chemie der Bor-Stickstoff-Verbindungen".
4. (May 2001). "Die Kristallstruktur von Bortriiodid, BI3". Zeitschrift für anorganische und allgemeine Chemie.
5. (2010). "Pressure-induced phase transition, metallization, and superconductivity in boron triiodide". Physical Review B.
6. (11 January 2006). "Kohleverflüssigung – Innovations Report".