Boron trioxide

Boron trioxide
Crystal structure of B2O3 [1]
Names
IUPAC name
Diboron trioxide
Other names
boron oxide, diboron trioxide, boron sesquioxide, boric oxide, boria
Boric anhydride
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.013.751 Edit this at Wikidata
EC Number
  • 215-125-8
11108
RTECS number
  • ED7900000
UNII
  • InChI=1S/B2O3/c3-1-5-2-4 checkY
    Key: JKWMSGQKBLHBQQ-UHFFFAOYSA-N checkY
  • InChI=1/B2O3/c3-1-5-2-4
    Key: JKWMSGQKBLHBQQ-UHFFFAOYAI
  • O=BOB=O
Properties
B2O3
Molar mass 69.6182 g/mol
Appearance white, glassy solid
Density 2.460 g/cm3, liquid;

2.55 g/cm3, trigonal;
3.11–3.146 g/cm3, monoclinic

Melting point 450 °C (842 °F; 723 K) (trigonal)
510 °C (tetrahedral)
Boiling point 1,860 °C (3,380 °F; 2,130 K) ,[2] sublimes at 1500 °C[3]
1.1 g/100mL (10 °C)
3.3 g/100mL (20 °C)
15.7 g/100mL (100 °C)
Solubility partially soluble in methanol
Acidity (pKa) ~ 4
−39.0·10−6 cm3/mol
Thermochemistry
66.9 J/(mol⋅K)
80.8 J/(mol⋅K)
−1254 kJ/mol
−832 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Irritant[4]
GHS labelling:
GHS08: Health hazard
Danger
H360FD
P201, P202, P281, P308+P313, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
0
0
Flash point noncombustible
Lethal dose or concentration (LD, LC):
3163 mg/kg (oral, mouse)[5]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 15 mg/m3[4]
REL (Recommended)
 TWA 10 mg/m3[4]
IDLH (Immediate danger)
 2000 mg/m3[4]
Supplementary data page
Boron trioxide (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Boron trioxide or diboron trioxide is the oxide of boron with the formula B2O3. It is a colorless transparent solid, almost always glassy (amorphous), which can be crystallized only with great difficulty. It is also called boric oxide[6] or boria.[7] It has many important industrial applications, chiefly in ceramics as a flux for glazes and enamels and in the production of glasses.

  1. ^ Cite error: The named reference a1 was invoked but never defined (see the help page).
  2. ^ High temperature corrosion and materials chemistry: proceedings of the Per Kofstad Memorial Symposium. Proceedings of the Electrochemical Society. The Electrochemical Society. 2000. p. 496. ISBN 978-1-56677-261-7.
  3. ^ Cite error: The named reference patnaik was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference PGCH was invoked but never defined (see the help page).
  5. ^ "Boron oxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  6. ^ Cite error: The named reference mccu1937 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference vish2015 was invoked but never defined (see the help page).