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Boric
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Boron
 

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Boric Oxide




  OtherNames Boron oxide, diboron trioxide, boron sesquioxide, boric oxide, boria, anhydric boric acid
  Section1 {{Chembox Identifiers
  CASNo 1303-86-2


  Section2 {{Chembox Properties
  Formula B<sub>2</sub>O<sub>3</sub>
  MolarMass 696182 g/mol
  Appearance Colourless, glassy solid
  Density 185 g/cm<sup>3</sup>, glass<br/>
  MeltingPt 480 &degC
  BoilingPt 1680 &degC
  Solubility 22 g/100 g


  Section3 {{Chembox Hazards




Boron oxide is one of the oxides of boron. It is white, glassy, and solid, also known as '''diboron trioxide''', formula B2O3. It is almost always found as the vitreous (amorphous) form; however, it can be crystallized after extensive Annealing . It is one of the most difficult compounds known to crystallize.

Glassy boron oxide (α-B2O3) is thought to be composed of boroxol rings which are six-membered rings composed of alternating 3-coordinate boron and 2-coordinate oxygen. The rings make a few BO3 triangles, but mostly link (polymerize) into ribbons and sheets. (1,2) The crystalline form (B2O3) is exclusively composed of BO3 triangles and is almost half as hard as quartz, 4 GPa Vickers . This trigonal, Quartz-like network undergoes a monoclinic, Coesite -like transformation of BO4 tetrahedra at several gigapascals and is 9.5 GPa (3).


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REFERENCES

#Eckert, H. Prog. ''NMR Spectrosc.'', 24 (1992) 159-293.
#"Quantitative study of the short range order in B,O, and B,S, by MAS and two-dimensional triple-quantum MAS 11B NMR". S.-J. Hwang, C. Femandez, J.P. Amoureux, J. Cho, S.W. Martin & M. Pruski. ''Solid State Nuclear Magnetic Resonance'' 8 (1997) 109-121.
#" Structural transformations in liquid, crystalline and glassy B2O3 under high pressure ". Institute for High Pressure Physics RAS and Japan Atomic Energy Research Institute. (2003).


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