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Boron trioxide

December 15, 2023

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.

Boron trioxide
Names
IUPAC name
Diboron trioxide
Other names
boron oxide, diboron trioxide, boron sesquioxide, boric oxide, boria
Boric anhydride
Identifiers
  • 1303-86-2 Y
3D model (JSmol)
  • Interactive image
ChEBI
  • CHEBI:30163 Y
ChemSpider
  • 452485 Y
ECHA InfoCard 100.013.751
EC Number
  • 215-125-8
11108
  • 518682
RTECS number
  • ED7900000
UNII
  • 483W67CPF4 Y
  • DTXSID7034387
  • InChI=1S/B2O3/c3-1-5-2-4 Y
    Key: JKWMSGQKBLHBQQ-UHFFFAOYSA-N Y
  • 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:
Danger
H360FD
P201, P202, P281, P308+P313, P405, P501
NFPA 704 (fire diamond)
Health 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).
Y verify (what is YN ?)

Structure edit

Boron trioxide has three known forms, one amorphous and two crystalline.

Amorphous form edit

The amorphous form (g-B2O3) is by far the most common. It 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 experiment.[8][9] It is now recognized, from experimental and theoretical studies,[10][11][12][13][14] that the fraction of boron atoms belonging to boroxol rings in glassy B2O3 is somewhere between 0.73 and 0.83, with 0.75 = 3/4 corresponding to a 1:1 ratio between ring and non-ring units. The number of boroxol rings decays in the liquid state with increasing temperature.[15]

Crystalline α form edit

The crystalline form (α-B2O3) is exclusively composed of BO3 triangles. It crystal structure was initially believed to be the enantiomorphic space groups P31(#144) and P32(#145), like γ-glycine;[16][17] but was later revised to the enantiomorphic space groups P3121(#152) and P3221(#154) in the trigonal crystal system, like α-quartz[18]

Crystallization of α-B2O3 from the molten state at ambient pressure is strongly kinetically disfavored (compare liquid and crystal densities). It can be obtained with prologed annealing of the amorphous solid ~200°C under at least 10 kbar of pressure.[19][1]

Crystalline β form edit

The trigonal network undergoes a coesite-like transformation to monoclinic β-B2O3 at several gigapascals (9.5 GPa).[20]

Preparation edit

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 out from sodium sulfate. It is then decanted, cooled and obtained in 96–97% purity.[3]

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.[21] Carefully controlled heating rate avoids gumming as water evolves.


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

2B2H6(g) + 3O2(g) → 2B2O3(s) + 6H2(g)
B2H6(g) + 3H2O(g) → B2O3(s) + 6H2(g)[22]

Reactions edit

Molten boron oxide attacks silicates. Containers can be passivated internally with a graphitized carbon layer obtained by thermal decomposition of acetylene.[23]

Applications edit

See also edit

References edit

  1. ^ a b Gurr, G. E.; Montgomery, P. W.; Knutson, C. D.; Gorres, B. T. (1970). "The Crystal Structure of Trigonal Diboron Trioxide". Acta Crystallographica B. 26 (7): 906–915. doi:10.1107/S0567740870003369.
  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. ^ a b Patnaik, P. (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill. p. 119. ISBN 978-0-07-049439-8. Retrieved 2009-06-06.
  4. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0060". National Institute for Occupational Safety and Health (NIOSH).
  5. ^ "Boron oxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  6. ^ L. McCulloch (1937): "A Crystalline Boric Oxide". Journal of the American Chemical Society, volume 59, issue 12, pages 2650–2652. doi:10.1021/ja01291a05
  7. ^ I.Vishnevetsky and M.Epstein (2015): "Solar carbothermic reduction of alumina, magnesia and boria under vacuum". Solar Energy, volume 111, pages 236-251 doi:10.1016/j.solener.2014.10.039
  8. ^ Ferlat, G.; Charpentier, T.; Seitsonen, A. P.; Takada, A.; Lazzeri, M.; Cormier, L.; Calas, G.; Mauri. F. (2008). "Boroxol Rings in Liquid and Vitreous B2O3 from First Principles". Phys. Rev. Lett. 101 (6): 065504. Bibcode:2008PhRvL.101f5504F. doi:10.1103/PhysRevLett.101.065504. PMID 18764473.
  9. ^ Ferlat, G.; Seitsonen, A. P.; Lazzeri, M.; Mauri, F. (2012). "Hidden polymorphs drive vitrification in B2O3". Nature Materials Letters. 11 (11): 925–929. arXiv:1209.3482. Bibcode:2012NatMa..11..925F. doi:10.1038/NMAT3416. PMID 22941329. S2CID 11567458.
  10. ^ Hung, I.; et al. (2009). "Determination of the bond-angle distribution in vitreous B2O3 by rotation (DOR) NMR spectroscopy". Journal of Solid State Chemistry. 182 (9): 2402–2408. Bibcode:2009JSSCh.182.2402H. doi:10.1016/j.jssc.2009.06.025.
  11. ^ Soper, A. K. (2011). "Boroxol rings from diffraction data on vitreous boron trioxide". J. Phys.: Condens. Matter. 23 (36): 365402. Bibcode:2011JPCM...23.5402S. doi:10.1088/0953-8984/23/36/365402. PMID 21865633. S2CID 5291179.
  12. ^ Joo, C.; et al. (2000). "The ring structure of boron trioxide glass". Journal of Non-Crystalline Solids. 261 (1–3): 282–286. Bibcode:2000JNCS..261..282J. doi:10.1016/s0022-3093(99)00609-2.
  13. ^ Zwanziger, J. W. (2005). "The NMR response of boroxol rings: a density functional theory study". Solid State Nuclear Magnetic Resonance. 27 (1–2): 5–9. doi:10.1016/j.ssnmr.2004.08.004. PMID 15589722.
  14. ^ Micoulaut, M. (1997). "The structure of vitreous B2O3 obtained from a thermostatistical model of agglomeration". Journal of Molecular Liquids. 71 (2–3): 107–114. doi:10.1016/s0167-7322(97)00003-2.
  15. ^ Alderman, O. L. G. Ferlat, G. Baroni, A. Salanne, M. Micoulaut, M. Benmore, C. J. Lin, A. Tamalonis, A. Weber, J. K. R. (2015). "Liquid B2O3 up to 1700K: X-ray diffraction and boroxol ring dissolution" (PDF). Journal of Physics: Condensed Matter. 27 (45): 455104. Bibcode:2015JPCM...27S5104A. doi:10.1088/0953-8984/27/45/455104. PMID 26499978. S2CID 21783488.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  16. ^ Gurr, G. E.; Montgomery, P. W.; Knutson, C. D.; Gorres, B. T. (1970). "The crystal structure of trigonal diboron trioxide". Acta Crystallographica B. 26 (7): 906–915. doi:10.1107/S0567740870003369.
  17. ^ Strong, S. L.; Wells, A. F.; Kaplow, R. (1971). "On the crystal structure of B2O3". Acta Crystallographica B. 27 (8): 1662–1663. doi:10.1107/S0567740871004515.
  18. ^ Effenberger, H.; Lengauer, C. L.; Parthé, E. (2001). "Trigonal B2O3 with Higher Space-Group Symmetry: Results of a Reevaluation". Monatshefte für Chemie. 132 (12): 1515–1517. doi:10.1007/s007060170008. S2CID 97795834.
  19. ^ Aziz, M. J.; Nygren, E.; Hays, J. F.; Turnbull, D. (1985). "Crystal Growth Kinetics of Boron Oxide Under Pressure". Journal of Applied Physics. 57 (6): 2233. Bibcode:1985JAP....57.2233A. doi:10.1063/1.334368.
  20. ^ Brazhkin, V. V.; Katayama, Y.; Inamura, Y.; Kondrin, M. V.; Lyapin, A. G.; Popova, S. V.; Voloshin, R. N. (2003). "Structural transformations in liquid, crystalline and glassy B2O3 under high pressure". JETP Letters. 78 (6): 393–397. Bibcode:2003JETPL..78..393B. doi:10.1134/1.1630134. S2CID 189764568.
  21. ^ Kocakuşak, S.; Akçay, K.; Ayok, T.; Koöroğlu, H. J.; Koral, M.; Savaşçi, Ö. T.; Tolun, R. (1996). "Production of anhydrous, crystalline boron oxide in fluidized bed reactor". Chemical Engineering and Processing. 35 (4): 311–317. doi:10.1016/0255-2701(95)04142-7.
  22. ^ AirProducts (2011). (PDF). Archived from the original (PDF) on 2015-02-04. Retrieved 2013-08-21. {{cite journal}}: Cite journal requires |journal= (help)
  23. ^ Morelock, C. R. (1961). "Research Laboratory Report #61-RL-2672M". General Electric. {{cite journal}}: Cite journal requires |journal= (help)

External links edit

  • US NIH hazard information. See NIH.
  • Material Safety Data Sheet
  • CDC - NIOSH Pocket Guide to Chemical Hazards - Boron oxide

December 15, 2023
boron, trioxide, diboron, trioxide, oxide, boron, with, formula, b2o3, colorless, transparent, solid, almost, always, glassy, amorphous, which, crystallized, only, with, great, difficulty, also, called, boric, oxide, boria, many, important, industrial, applica. 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 Boron trioxide NamesIUPAC name Diboron trioxideOther names boron oxide diboron trioxide boron sesquioxide boric oxide boria Boric anhydrideIdentifiersCAS Number 1303 86 2 Y3D model JSmol Interactive imageChEBI CHEBI 30163 YChemSpider 452485 YECHA InfoCard 100 013 751EC Number 215 125 8Gmelin Reference 11108PubChem CID 518682RTECS number ED7900000UNII 483W67CPF4 YCompTox Dashboard EPA DTXSID7034387InChI InChI 1S B2O3 c3 1 5 2 4 YKey JKWMSGQKBLHBQQ UHFFFAOYSA N YInChI 1 B2O3 c3 1 5 2 4Key JKWMSGQKBLHBQQ UHFFFAOYAISMILES O BOB OPropertiesChemical formula B2O3Molar mass 69 6182 g molAppearance white glassy solidDensity 2 460 g cm3 liquid 2 55 g cm3 trigonal 3 11 3 146 g cm3 monoclinicMelting 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 Solubility in water 1 1 g 100mL 10 C 3 3 g 100mL 20 C 15 7 g 100mL 100 C Solubility partially soluble in methanolAcidity pKa 4Magnetic susceptibility x 39 0 10 6 cm3 molThermochemistryHeat capacity C 66 9 J mol K Std molarentropy S 298 80 8 J mol K Std enthalpy offormation DfH 298 1254 kJ molGibbs free energy DfG 832 kJ molHazardsOccupational safety and health OHS OSH Main hazards Irritant 4 GHS labelling PictogramsSignal word DangerHazard statements H360FDPrecautionary statements P201 P202 P281 P308 P313 P405 P501NFPA 704 fire diamond 200Flash point noncombustibleLethal dose or concentration LD LC LD50 median dose 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 pageBoron trioxide data page Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Y verify what is Y N Infobox references Contents 1 Structure 1 1 Amorphous form 1 2 Crystalline a form 1 3 Crystalline b form 2 Preparation 3 Reactions 4 Applications 5 See also 6 References 7 External linksStructure editBoron trioxide has three known forms one amorphous and two crystalline Amorphous form edit The amorphous form g B2O3 is by far the most common It 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 experiment 8 9 It is now recognized from experimental and theoretical studies 10 11 12 13 14 that the fraction of boron atoms belonging to boroxol rings in glassy B2O3 is somewhere between 0 73 and 0 83 with 0 75 3 4 corresponding to a 1 1 ratio between ring and non ring units The number of boroxol rings decays in the liquid state with increasing temperature 15 Crystalline a form edit The crystalline form a B2O3 is exclusively composed of BO3 triangles It crystal structure was initially believed to be the enantiomorphic space groups P31 144 and P32 145 like g glycine 16 17 but was later revised to the enantiomorphic space groups P3121 152 and P3221 154 in the trigonal crystal system like a quartz 18 Crystallization of a B2O3 from the molten state at ambient pressure is strongly kinetically disfavored compare liquid and crystal densities It can be obtained with prologed annealing of the amorphous solid 200 C under at least 10 kbar of pressure 19 1 Crystalline b form edit The trigonal network undergoes a coesite like transformation to monoclinic b B2O3 at several gigapascals 9 5 GPa 20 Preparation editBoron trioxide is produced by treating borax with sulfuric acid in a fusion furnace At temperatures above 750 C the molten boron oxide layer separates out from sodium sulfate It is then decanted cooled and obtained in 96 97 purity 3 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 H2O2 HBO2 B2O3 H2OBoric acid goes to anhydrous microcrystalline B2O3 in a heated fluidized bed 21 Carefully controlled heating rate avoids gumming as water evolves Boron oxide will also form when diborane B2H6 reacts with oxygen in the air or trace amounts of moisture 2B2H6 g 3O2 g 2B2O3 s 6H2 g B2H6 g 3H2O g B2O3 s 6H2 g 22 Reactions editMolten boron oxide attacks silicates Containers can be passivated internally with a graphitized carbon layer obtained by thermal decomposition of acetylene 23 Applications editMajor component of borosilicate glass Fluxing agent for glass and enamels citation needed An additive used in glass fibres optical fibres The inert capping layer in the Liquid Encapsulation Czochralski process for the production of gallium arsenide single crystal As an acid catalyst in organic synthesis As a starting material for the production of other boron compounds such as boron carbideSee also editboron suboxide boric acid sassolite Tris 2 2 2 trifluoroethyl borateReferences edit a b Gurr G E Montgomery P W Knutson C D Gorres B T 1970 The Crystal Structure of Trigonal Diboron Trioxide Acta Crystallographica B 26 7 906 915 doi 10 1107 S0567740870003369 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 a b Patnaik P 2003 Handbook of Inorganic Chemical Compounds McGraw Hill p 119 ISBN 978 0 07 049439 8 Retrieved 2009 06 06 a b c d NIOSH Pocket Guide to Chemical Hazards 0060 National Institute for Occupational Safety and Health NIOSH Boron oxide Immediately Dangerous to Life or Health Concentrations IDLH National Institute for Occupational Safety and Health NIOSH L McCulloch 1937 A Crystalline Boric Oxide Journal of the American Chemical Society volume 59 issue 12 pages 2650 2652 doi 10 1021 ja01291a05 I Vishnevetsky and M Epstein 2015 Solar carbothermic reduction of alumina magnesia and boria under vacuum Solar Energy volume 111 pages 236 251 doi 10 1016 j solener 2014 10 039 Ferlat G Charpentier T Seitsonen A P Takada A Lazzeri M Cormier L Calas G Mauri F 2008 Boroxol Rings in Liquid and Vitreous B2O3 from First Principles Phys Rev Lett 101 6 065504 Bibcode 2008PhRvL 101f5504F doi 10 1103 PhysRevLett 101 065504 PMID 18764473 Ferlat G Seitsonen A P Lazzeri M Mauri F 2012 Hidden polymorphs drive vitrification in B2O3 Nature Materials Letters 11 11 925 929 arXiv 1209 3482 Bibcode 2012NatMa 11 925F doi 10 1038 NMAT3416 PMID 22941329 S2CID 11567458 Hung I et al 2009 Determination of the bond angle distribution in vitreous B2O3 by rotation DOR NMR spectroscopy Journal of Solid State Chemistry 182 9 2402 2408 Bibcode 2009JSSCh 182 2402H doi 10 1016 j jssc 2009 06 025 Soper A K 2011 Boroxol rings from diffraction data on vitreous boron trioxide J Phys Condens Matter 23 36 365402 Bibcode 2011JPCM 23 5402S doi 10 1088 0953 8984 23 36 365402 PMID 21865633 S2CID 5291179 Joo C et al 2000 The ring structure of boron trioxide glass Journal of Non Crystalline Solids 261 1 3 282 286 Bibcode 2000JNCS 261 282J doi 10 1016 s0022 3093 99 00609 2 Zwanziger J W 2005 The NMR response of boroxol rings a density functional theory study Solid State Nuclear Magnetic Resonance 27 1 2 5 9 doi 10 1016 j ssnmr 2004 08 004 PMID 15589722 Micoulaut M 1997 The structure of vitreous B2O3 obtained from a thermostatistical model of agglomeration Journal of Molecular Liquids 71 2 3 107 114 doi 10 1016 s0167 7322 97 00003 2 Alderman O L G Ferlat G Baroni A Salanne M Micoulaut M Benmore C J Lin A Tamalonis A Weber J K R 2015 Liquid B2O3 up to 1700K X ray diffraction and boroxol ring dissolution PDF Journal of Physics Condensed Matter 27 45 455104 Bibcode 2015JPCM 27S5104A doi 10 1088 0953 8984 27 45 455104 PMID 26499978 S2CID 21783488 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Gurr G E Montgomery P W Knutson C D Gorres B T 1970 The crystal structure of trigonal diboron trioxide Acta Crystallographica B 26 7 906 915 doi 10 1107 S0567740870003369 Strong S L Wells A F Kaplow R 1971 On the crystal structure of B2O3 Acta Crystallographica B 27 8 1662 1663 doi 10 1107 S0567740871004515 Effenberger H Lengauer C L Parthe E 2001 Trigonal B2O3 with Higher Space Group Symmetry Results of a Reevaluation Monatshefte fur Chemie 132 12 1515 1517 doi 10 1007 s007060170008 S2CID 97795834 Aziz M J Nygren E Hays J F Turnbull D 1985 Crystal Growth Kinetics of Boron Oxide Under Pressure Journal of Applied Physics 57 6 2233 Bibcode 1985JAP 57 2233A doi 10 1063 1 334368 Brazhkin V V Katayama Y Inamura Y Kondrin M V Lyapin A G Popova S V Voloshin R N 2003 Structural transformations in liquid crystalline and glassy B2O3 under high pressure JETP Letters 78 6 393 397 Bibcode 2003JETPL 78 393B doi 10 1134 1 1630134 S2CID 189764568 Kocakusak S Akcay K Ayok T Kooroglu H J Koral M Savasci O T Tolun R 1996 Production of anhydrous crystalline boron oxide in fluidized bed reactor Chemical Engineering and Processing 35 4 311 317 doi 10 1016 0255 2701 95 04142 7 AirProducts 2011 Diborane Storage amp Delivery PDF Archived from the original PDF on 2015 02 04 Retrieved 2013 08 21 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Morelock C R 1961 Research Laboratory Report 61 RL 2672M General Electric a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help External links editNational Pollutant Inventory Boron and compounds Australian Government information US NIH hazard information See NIH Material Safety Data Sheet CDC NIOSH Pocket Guide to Chemical Hazards Boron oxide Retrieved from https en wikipedia org w index php title Boron trioxide amp oldid 1179704741, wikipedia, wiki, book, books, library,

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