What is "boron trioxide"

n. (context inorganic compound English) A white solid, of empirical formula B₂O₃, that is an inorganic polymer, and is used in making glass and enamel and for synthesizing other boron compounds.

Boron trioxide (or diboron trioxide) is one of the oxides of boron. It is a white, glassy solid with the formula BO. 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-BO) 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 BO triangles, but mostly link (polymerize) into ribbons and sheets. The crystalline form (α-BO) (see structure in the infobox) is exclusively composed of BO triangles. This trigonal, quartz-like network undergoes a coesite-like transformation to monoclinic β-BO at several gigapascals (9.5 GPa).

This page provides supplementary chemical data on boron trioxide.