Bismuth Sulfate Powder

Product Name:  Bismuth Sulfate Powder

Boron Trioxide Powder

Product Name: Boron Trioxide Powder

Boron trioxide Powder Description :

Boron trioxide Powder 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 many boroxol rings, this view was initially controversial, but such models have recently been constructed and exhibit properties in excellent agreement with the experiment.

It is now recognized, from experimental and theoretical studies, that the fraction of boron atoms belonging to boroxol rings in glassy B₂O₃ is somewhere between 0.73 and 0.83, with 0.75 correspondings to a 1:1 ratio between the ring and non-ring units.

The number of boroxol rings decays in the liquid state with increasing temperature.

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 is produced by treating borax with sulfuric acid in a fusion furnace.

At temperatures above 750 °C, the molten boron oxide layer separates from sodium sulfate. It is then decanted, cooled, and obtained in 96–97% purity.

Another method is heating boric acid above ~300 °C. Boric acid will initially decompose into steam, (H₂O_(g)) and metaboric acid (HBO₂) at around 170 °C and further heating above 300 °C will produce more steam and diboron trioxide. The reactions are:

H₃BO₃ → HBO₂ + H₂O

2 HBO₂ → B₂O₃ + H₂O

Boric acid goes to anhydrous microcrystalline B₂O₃ in a heated fluidized bed. A carefully controlled heating rate avoids gumming as water evolves.

Molten boron oxide attacks silicates. Internally graphitized tubes via acetylene thermal decomposition are passivated.

Crystallization of molten α-B₂O₃ at ambient pressure is strongly kinetically disfavored (compare liquid and crystal densities).

The threshold conditions for the crystallization of the amorphous solid are 10 kbar and ~200 °C.

Its proposed crystal structure in enantiomorphic space groups has been revised to enantiomorphic space groups P3₁21(#152); P3₂21(#154) (e.g., α-quartz).

Boron oxide will also form when diborane (B₂H₆) reacts with oxygen in the air or trace amounts of moisture.

Boron trioxide Powder Related Information