Boron trioxide
Boron trioxide (or diboron trioxide) is one of the oxides of boron. It is a white, glassy solid with the formula B2O3. It is almost always found as the vitreous (amorphous) form; however, it can be crystallized after extensive annealing (that is, under prolonged heat).
Glassy boron oxide (g-B2O3) is thought to be composed of boroxol rings which are six-membered rings composed of alternating 3-coordinate boron and 2-coordinate oxygen. Because of the difficulty of building disordered models at the correct density with a large number of boroxol rings, this view was initially controversial, but such models have recently been constructed and exhibit spectroscopic properties in excellent agreement with experiment. The rings are thought to make a few BO3 triangles, but mostly link (polymerize) into ribbons and sheets. The crystalline form (α-B2O3) (see structure in the infobox) is exclusively composed of BO3 triangles. This trigonal, quartz-like network undergoes a coesite-like transformation to monoclinic β-B2O3 at several gigapascals (9.5 GPa).
Boron trioxide (data page)
This page provides supplementary chemical data on boron trioxide.
Material Safety Data Sheet
Structure and properties
Thermodynamic properties
Spectral data
References
Except where noted otherwise, data relate to standard ambient temperature and pressure.
Disclaimer applies.
Podcasts:
