Boron: Difference between revisions
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(Created page with "{{Compound|name=Boron|chemf=B|density=2.33 to 2.53|num=5|group=Metalloids|stp_p=solid|mp=2076|bp=3927|mm=10.81|nfpa_h=2|nfpa_f=3}} Elemental Boron is rarely required. Normally...") |
m (Text replacement - "glass" to "'''glass'''") |
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===Primary=== | ===Primary=== | ||
* Borosilicate | * Borosilicate '''glass''' (as oxide) | ||
* Feedstock for [[sodium borohydride]] | * Feedstock for [[sodium borohydride]] | ||
===Secondary=== | ===Secondary=== |
Latest revision as of 14:06, 26 June 2019
Chemical formula | B |
---|---|
Atomic Number | 5 |
OTP appearance | solid |
Molar Mass(g/mol) | 10.81 |
Density(g/cc) | 2.33 to 2.53 |
Melting Point(°C) | 2076 |
Boiling Point(°C) | 3927 |
NFPA 704 |
Elemental Boron is rarely required. Normally it is used in a reduced state.
Uses
Justification Questioned
Primary
- Borosilicate glass (as oxide)
- Feedstock for sodium borohydride
Secondary
- Detergents (as sodium tetraborate)
- Fire retardants for wood and cloth
- Semiconductor dopant
- High-hardness metal alloys
Natural Occurrence
- Elemental boron does not occur naturally.
- sodium boron hydroxide occurrs in the minerals kernite and borax
- calcium boron hydroxide occurrs as the mineral colemanite
Hazards
Production
Extraction
- Produce boric acid by combining the boron ore with a mineral acid such as hydrochloric, sulfuric or phosphoric
- Borax: Na2B4O7(H2O)10 + 2 HCl → 5 H2O + 2 NaCl + 4 H3BO3
- Kernite: Na2B4O6(OH)2(H2O)3 + 2 HCl + H2O → 2 NaCl + 4 H3BO3
- Colemanite: CaB3O4(OH)3(H2O) + H2SO4 + H2O → CaSO4 + 3 H3BO3
- Howlite: Ca2B5SiO9(OH)5 + 2 H2SO4 + 3 H2O → SiO2 + 2 CaSO4 + 5 H3BO3
- Produce boric oxide via thermal decomposition of boric acid
- 2 H3BO3{B2O3 + 3 H2O300°C}→
- 2 H3BO3
- Produce elemental boron via magnesiothermic reduction of boric oxide
- B2O3 + 3 Mg → 2 B + 3 MgO