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About Boron

Boron Bohr Model

Boron is the only non-metallic element of the periodic table family that includes aluminum, gallium, and indium. Classified as a metalloid, or semimetal, the element can mimic the typical behavior of either a metal or a nonmetal, depending on the type of reaction involved. The only nonmetal with 3 electrons in its outer shell to contribute to bonds, boron is a strong electron-pair acceptor (a strong Lewis acid) with a very high affinity for oxygen and is one of the few elements along with carbon and nitrogen known to form stable compounds with triple bonds. Like its neighbor carbon, elemental boron has multiple allotropes, or structural forms, all of which are extremely hard: crystalline boron is a brittle, lustrous sold ranging in appearance from jet black to silvery gray that is a poor electrical conductor; another crystalline form is red in appearance; and amorphous boron is a dark brown powder lower in density than the crystalline forms. Boron is also similar to carbon in that both are able to form covalently bonded networks of molecules, and the two are the only elements that form multiple hydride compounds.

The name boron comes from the Persian or Arabic terms for the mineral borax (burah or buraq, respectively). Borax and boric acid have been known since ancient times in Europe, Tibet, and China, being used by craftsmen to reduce melting point of other materials used in glassmaking and other applications. The first written reference to boron-containing compounds was by the 9th century Persian alchemist Rhazes, who classified one of six groups of minerals as “boraces.” The element was first isolated in 1808 independently by English chemist Sir Humphry Davy and French chemists Joseph-Louis Gay-Lussac and Louis-Jacque Thenard. Later, Henry Moisson isolated a more pure sample by reducing boron trioxide with magnesium, a method that still bears his name.

The chief commercial application for boron is the use of borax (sodium tetraborate decahydrate, Na2B4O7• 10H2O) in soaps and household detergents, water-softening compounds to remove alkaline-earth ions like calcium and magnesium from water, adhesives, cosmetics, fire retardants, and glazes. It is also used to disinfect fruit and lumber, and additionally plays a role in the manufacturing of paper, leather, and plastics. Sodium borate is used to manufacture borosilicate glass, a high-strength glass that is resistant to heat, chemical attack, and thermal shock; applications for borosilicate glasses include bakeware, laboratory containers, and high quality optical glass, as well as serving as precursor materials for glass fiber insulation and textile glass fibers. Boron-containing glasses are generally preferred for flat display panel glass, as in LCDs, as such glasses have superior electrical and strength characteristics as compared to other glasses available for these applications.

Boron is also used in a number of alloy products, including neodymium iron boron (NdFeB) magnets, which are the strongest magnets available and are found in microphones, magnetic switches, speakers, particle accelerators, and dozens of other electronic applications. Boron is also an important dopant molecule used in the production of semiconductor crystals. A number of boron compounds are also important in electronics, including the neutron-detecting scintillator material cadmium borate, and boron subphtalocyanines, organoboron dye molecules with optical properties that are of use in organic LEDs and photovoltaics. Some other organoboron compounds have medical uses, either as treatment agents, or as diagnostic markers.

Though not technically a metal, boron is playing an increasingly important role in advanced materials science due in part to the unique properties of hexagonal boron nitride (hBN), a semiconducting material capable of forming two-dimensional sheets similar to carbon-based graphene. Boron nitride and boron carbide are both superhard materials, and are used widely in cutting tools and as abrasives. Boron carbide is also a strong, heat-resistant material with a high strength-to-weight ratio, making it useful for armor and bulletproof vests. Additionally, boron carbide can absorb neutrons without forming dangerous long-lived radioactive waste, and it is therefore an important material in nuclear power plants. A number of other engineered advanced materials also contain boron. These include borane derivatives, of interest for a variety of specialized applications including hydrogen storage, and lithium borosilicide, a key component of lithium ion batteries.

Boron is relatively scarce element in the universe, produced only via cosmic ray spallation rather than in the cores of stars. Despite composing merely 0.0003% of the earth’s crust by mass, boron is very susceptible to fractionation in the earth’s crust and therefore tends to be concentrated in an deposits of an extensive array of borate (boron oxide)-containing minerals such as borax and kernite (its most common sources), colemanite, and ulexite. It is also present in meteorites, seawater, as a trace element in soils, and silicate minerals like tourmaline and datolite. Methods of obtaining boron include heating the oxide with powdered magnesium or aluminum, or passing an electric current through molten boron trichloride. The city of Boron in California, United States was named after the element and is home to the U.S. Borax Boron Mine, the world’s largest borax mine. The other major source of the element is deposits in Turkey, although the element also is known to accumulate in areas of thermal and volcanic activity.


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Boron has an energy band gap of 1.50 to 1.56 eV, which is higher than that of either silicon or germanium. Optical characteristics include transmitting portions of the infrared. Boron is a poor conductor of electricity at room temperature but a good conductor at high temperature. Amorphous boron is used in pyrotechnic flares to provide a distinctive green color, and in rockets as an igniter. Boric acid is an important boron compound with major markets in textile products. Boron compounds High Purity (99.999%) Boron Oxide (B2O3) Powder High Purity (99.999%) Boron (B) Sputtering Target are used extensively in the manufacture of borosilicate glasses. The isotope Boron-10 is used as a control for nuclear reactors, as a shield for nuclear radiation, and in instruments used for detecting neutrons. Boron nitride has remarkable properties and can be used to make a material as hard as diamond. The nitride also behaves like an electrical insulator but conducts heat like a metal. Boron is available in forms with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental forms include pellets, rod, wire and granules for evaporation source material purposes. Boron oxide is available in powder and dense pellet form for such uses as optical coating and thin film applications. Boron fluoride is an insoluble source of fluoride for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Boron is also available in soluble forms including chlorides, and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Boron Properties

Boron (B) atomic and molecular weight, atomic number and elemental symbolBoron is a Block P, Group 13, Period 2 element. Boron Bohr ModelThe number of electrons in each of boron's shells is 2, 3 and its electron configuration is [He] 2s2 2p1. The boron atom has a radius of and its Van der Waals radius is Elemental Boron In its elemental form, CAS 7440-42-8, boron has a black-brown appearance. Along with carbon and nitrogen, boron is one of the few elements in the periodic table known to form stable compounds featuring triple bonds. Boron is found in borates, borax, boric acid, colemanite, kernite, and ulexite. Boron was discovered by Joseph Louis Gay-Lussac and Louis Jacques Thénard in 1808. It was first isolated by Humphry Davy, also in 1808. The name Boron originates from a combination of carbon and the Arabic word buraqu meaning borax.

Symbol: B
Atomic Number: 5
Atomic Weight: 10.81
Element Category: metalloid
Group, Period, Block: 13, 2, p
Color: black
Other Names: Bore, Bor
Melting Point: 2077 °C, 3770.6 °F, 2350.15 K
Boiling Point: 4000 °C, 7232 °F, 4273.15 K
Density: 2.3 g/cm3 @ 20 °C
Liquid Density @ Melting Point: 2.08 g/cm3
Density @ 20°C: 2.34 g/cm3
Density of Solid: 2460 kg·m3
Specific Heat: 0.245 Cal/g/K @ 25 °C
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 22.2
Heat of Vaporization (kJ·mol-1): 504.5
Heat of Atomization (kJ·mol-1): 557.64
Thermal Conductivity: 0.274 W/cm/K @ 298.2 K
Thermal Expansion: 5–7 µm·m-1·K-1 @ 25 °C
Electrical Resistivity: 1.8 x 1012 µΩ·cm @ 0 °C
Tensile Strength: N/A
Molar Heat Capacity: 11.087 J·mol-1·K-1
Young's Modulus: N/A
Shear Modulus: N/A
Bulk Modulus: N/A
Poisson Ratio: N/A
Mohs Hardness: ~9.5
Vickers Hardness: N/A
Brinell Hardness: N/A
Speed of Sound: (20 °C) 16,200 m·s-1
Pauling Electronegativity: 2.04
Sanderson Electronegativity: 2.28
Allred Rochow Electronegativity: 2.01
Mulliken-Jaffe Electronegativity: 2.04 (sp2 orbital)
Allen Electronegativity: 2.051
Pauling Electropositivity: 1.96
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 5
Protons: 5
Neutrons: 6
Electron Configuration: [He] 2s2 2p1
Atomic Radius: 90 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 84±3 pm
Covalent Radius (Å): 0.84
Van der Waals Radius: 192 pm
Oxidation States: 3, 2, 1 (mildly acidic oxide)
Phase: Solid
Crystal Structure: rhombohedral
Magnetic Ordering: diamagnetic
Electron Affinity (kJ·mol-1) 26.98
1st Ionization Energy: 800.64 kJ·mol-1
2nd Ionization Energy: 2427.09 kJ·mol-1
3rd Ionization Energy: 3659.78 kJ·mol-1
CAS Number: 7440-42-8
EC Number: 231-151-2
MDL Number: MFCD00134034
Beilstein Number: N/A
SMILES Identifier: B
InChI Identifier: InChI=1S/B
PubChem CID: 5462311
ChemSpider ID: 4575371
Earth - Total: 9.6 ppb
Mercury - Total: 0.11 ppb
Venus - Total: 10.0 ppb
Earth - Seawater (Oceans), ppb by weight: 4440
Earth - Seawater (Oceans), ppb by atoms: 2500
Earth -  Crust (Crustal Rocks), ppb by weight: 8700
Earth -  Crust (Crustal Rocks), ppb by atoms: 17000
Sun - Total, ppb by weight: 2
Sun - Total, ppb by atoms: 0.2
Stream, ppb by weight: 10
Stream, ppb by atoms: 1
Meterorite (Carbonaceous), ppb by weight: 1600
Meterorite (Carbonaceous), ppb by atoms: 3000
Typical Human Body, ppb by weight: 700
Typical Human Body, ppb by atom: 410
Universe, ppb by weight: 1
Universe, ppb by atom: 0.1
Discovered By: Joseph Louis Gay-Lussac and Louis Jacques Thénard
Discovery Date: 1808
First Isolation: Humphry Davy (9 July 1808)

Health, Safety & Transportation Information for Boron

Boron in its elemental form is not toxic. Safety data for Boron and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental Boron.

Safety Data
Signal Word Warning
Hazard Statements H302
Hazard Codes Xn
Risk Codes 22
Safety Precautions N/A
RTECS Number ED7350000
Transport Information N/A
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)
Exclamation Mark-Acute Toxicity
Review and Print SDS for Boron Metal


Date Accessed: 05/15/2015
Date Revised: 05/15/2015


Product Name: Boron Metal

Product Number: All applicable American Elements product codes, e.g. BO-E-02, BO-E-03, BO-E-04, BO-E-05

CAS #: 7440-42-8

Relevant identified uses of the substance: Scientific research and development

Supplier details:
American Elements
1093 Broxton Ave. Suite 2000
Los Angeles, CA 90024
Tel: +1 310-208-0551
Fax: +1 310-208-0351

Emergency telephone number:
Domestic, North America +1 800-424-9300
International +1 703-527-3887


Classification of the substance or mixture
Classification according to Regulation (EC) No 1272/2008
Acute Tox. 4 H302 Harmful if swallowed.
Classification according to Directive 67/548/EEC or Directive 1999/45/EC
Xn; Harmful
R22: Harmful if swallowed.
Information concerning particular hazards for human and environment:
Not applicable
Hazards not otherwise classified
No information known.
Label elements
Labelling according to Regulation (EC) No 1272/2008
The substance is classified and labeled according to the CLP regulation.
Hazard pictograms

Exclamation Mark - GHS07

Signal word
Hazard statements
H302 Harmful if swallowed.
Precautionary statements
P264 Wash thoroughly after handling.
P270 Do not eat, drink or smoke when using this product.
P301+P312 IF SWALLOWED: Call a POISON CENTER/doctor/.../if you feel unwell.
P330 Rinse mouth.
P501 Dispose of contents/container in accordance with local/regional/
national/international regulations.
WHMIS classification
Not controlled
Classification system
HMIS ratings (scale 0-4)
(Hazardous Materials Identification System)

Health (acute effects) = 1
Flammability = 0
Physical Hazard = 0
Other hazards
Results of PBT and vPvB assessment
Not applicable.
Not applicable.


Chemical characterization: Substances
CAS# Description:
7440-42-8 Boron
Identification number(s):
EC number:


Description of first aid measures
After inhalation
Supply fresh air. If required, provide artificial respiration. Keep patient warm.
Seek immediate medical advice.
After skin contact
Immediately wash with water and soap and rinse thoroughly.
Seek immediate medical advice.
After eye contact
Rinse opened eye for several minutes under running water. Then consult a doctor.
After swallowing
Seek medical treatment.
Information for doctor
Most important symptoms and effects, both acute and delayed
No further relevant information available.
Indication of any immediate medical attention and special treatment needed
No further relevant information available.


Extinguishing media
Suitable extinguishing agents
Special powder for metal fires. Do not use water.
For safety reasons unsuitable extinguishing agents
Special hazards arising from the substance or mixture
If this product is involved in a fire, the following can be released:
Boron oxide
Advice for firefighters
Protective equipment:
Wear self-contained respirator.
Wear fully protective impervious suit.


Personal precautions, protective equipment and emergency procedures
Wear protective equipment. Keep unprotected persons away.
Ensure adequate ventilation
Environmental precautions:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow product to reach sewage system or any water course.
Do not allow to penetrate the ground/soil.
Methods and material for containment and cleaning up:
Dispose of contaminated material as waste according to section 13.
Prevention of secondary hazards:
No special measures required.
Reference to other sections
See Section 7 for information on safe handling
See Section 8 for information on personal protection equipment.
See Section 13 for disposal information.


Precautions for safe handling
Keep container tightly sealed.
Store in cool, dry place in tightly closed containers.
Ensure good ventilation at the workplace.
Information about protection against explosions and fires:
No information known.
Conditions for safe storage, including any incompatibilities
Requirements to be met by storerooms and receptacles:
No special requirements.
Information about storage in one common storage facility:
Store away from oxidizing agents.
Store away from halogens.
Do not store with interhalogens.
Further information about storage conditions:
Keep container tightly sealed.
Store in cool, dry conditions in well sealed containers.
Specific end use(s)
No further relevant information available.


Additional information about design of technical systems:
Properly operating chemical fume hood designed for hazardous chemicals and having an average face velocity of at least 100 feet per minute.
Control parameters
Components with limit values that require monitoring at the workplace:
The product does not contain any relevant quantities of materials with critical values that have to be monitored at the workplace.
Additional information:
No data
Exposure controls
Personal protective equipment
General protective and hygienic measures
The usual precautionary measures for handling chemicals should be followed.
Keep away from foodstuffs, beverages and feed.
Remove all soiled and contaminated clothing immediately.
Wash hands before breaks and at the end of work.
Maintain an ergonomically appropriate working environment.
Breathing equipment:
Use suitable respirator when high concentrations are present.
Protection of hands:
Impervious gloves
Check protective gloves prior to each use for their proper condition.
The selection of suitable gloves not only depends on the material, but also on quality. Quality will vary from manufacturer to manufacturer.
Penetration time of glove material (in minutes)
Not determined
Eye protection:
Safety glasses
Body protection:
Protective work clothing


Information on basic physical and chemical properties
General Information
Form: Solid in various forms
Color: Dark grey
Odor: Odorless
Odor threshold: Not determined.
pH-value: Not applicable.
Change in condition
Melting point/Melting range: 2075 °C (3767 °F)
Boiling point/Boiling range: 2550 °C (4622 °F)
Sublimation temperature / start: Not determined
Flammability (solid, gaseous)
Not determined.
Ignition temperature: 700 °C (1292 °F)
Decomposition temperature: Not determined
Auto igniting: Not determined.
Danger of explosion: Not determined.
Explosion limits:
Lower: Not determined
Upper: Not determined
Vapor pressure: Not applicable.
Density at 20 °C (68 °F): 2.34 g/cm³ (19.527 lbs/gal)
Relative density
Not determined.
Vapor density
Not applicable.
Evaporation rate
Not applicable.
Solubility in / Miscibility with Water: Insoluble
Partition coefficient (n-octanol/water): Not determined.
dynamic: Not applicable.
kinematic: Not applicable.
Other information
No further relevant information available.


No information known.
Chemical stability
Stable under recommended storage conditions.
Thermal decomposition / conditions to be avoided:
Decomposition will not occur if used and stored according to specifications.
Possibility of hazardous reactions
No dangerous reactions known
Conditions to avoid
No further relevant information available.
Incompatible materials:
Oxidizing agents
Hazardous decomposition products:
Boron oxide


Information on toxicological effects
Acute toxicity:
Harmful if swallowed.
The Registry of Toxic Effects of Chemical Substances (RTECS) contains acute toxicity data for components in this product.
LD/LC50 values that are relevant for classification:
Oral LD50 650 mg/kg (rat)
Skin irritation or corrosion:
May cause irritation
Eye irritation or corrosion:
May cause irritation
No sensitizing effects known.
Germ cell mutagenicity:
No effects known.
EPA-I: Data are inadequate for an assessment of human carcinogenic potential.
Reproductive toxicity:
The Registry of Toxic Effects of Chemical Substances (RTECS) contains reproductive data for this substance.
Specific target organ system toxicity - repeated exposure:
No effects known.
Specific target organ system toxicity - single exposure:
No effects known.
Aspiration hazard:
No effects known.
Subacute to chronic toxicity:
No effects known.
Additional toxicological information:
To the best of our knowledge the acute and chronic toxicity of this substance is not fully known.


Aquatic toxicity:
No further relevant information available.
Persistence and degradability
No further relevant information available.
Bioaccumulative potential
No further relevant information available.
Mobility in soil
No further relevant information available.
Additional ecological information:
General notes:
Do not allow material to be released to the environment without proper governmental permits.
Avoid transfer into the environment.
Results of PBT and vPvB assessment
Not applicable.
Not applicable.
Other adverse effects
No further relevant information available.


Waste treatment methods
Consult state, local or national regulations to ensure proper disposal.
Uncleaned packagings:
Disposal must be made according to official regulations.


Not applicable
UN proper shipping name
Not applicable
Transport hazard class(es)
Not applicable
Packing group
Not applicable
Environmental hazards:
Not applicable.
Special precautions for user
Not applicable.
Transport in bulk according to Annex II of MARPOL73/78 and the IBC Code
Not applicable.
Transport/Additional information:
Marine Pollutant (DOT):


Safety, health and environmental regulations/legislation specific for the substance or mixture
National regulations
All components of this product are listed in the U.S. Environmental Protection Agency Toxic Substances Control Act Chemical substance Inventory.
All components of this product are listed on the Canadian Domestic Substances List (DSL).
SARA Section 313 (specific toxic chemical listings)
Substance is not listed.
California Proposition 65
Prop 65 - Chemicals known to cause cancer
Substance is not listed.
Prop 65 - Developmental toxicity
Substance is not listed.
Prop 65 - Developmental toxicity, female
Substance is not listed.
Prop 65 - Developmental toxicity, male
Substance is not listed.
Information about limitation of use:
For use only by technically qualified individuals.
Other regulations, limitations and prohibitive regulations
Substance of Very High Concern (SVHC) according to the REACH Regulations (EC) No. 1907/2006.
Substance is not listed.
The conditions of restrictions according to Article 67 and Annex XVII of the Regulation (EC) No 1907/2006 (REACH) for the manufacturing, placing on the market and use must be observed.
Substance is not listed.
Annex XIV of the REACH Regulations (requiring Authorisation for use)
Substance is not listed.
REACH - Pre-registered substances
Substance is listed.
Chemical safety assessment:
A Chemical Safety Assessment has not been carried out.


Safety Data Sheet according to Regulation (EC) No. 1907/2006 (REACH). The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. American Elements shall not be held liable for any damage resulting from handling or from contact with the above product. See reverse side of invoice or packing slip for additional terms and conditions of sale. COPYRIGHT 1997-2016 AMERICAN ELEMENTS. LICENSED GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLY.

Boron Isotopes

Boron has two stable isotopes: 10B and 11B.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
6B 6.04681(75)# N/A Unknown N/A N/A -0.74 -
7B 7.02992(8) 350(50)E-24 s [1.4(2) ] p to 6Be (3/2-) N/A 23.08 -
8B 8.0246072(11) 770(3) ms EC to 8Be; 4He; EC + 2 a to n 2+ 1.0355 36.1 -
9B 9.0133288(11) 800(300)E-21 s [0.54(21) keV] 2a to 1H; p to 8Be 3/2- 1.8006 54.71 -
10B 10.0129370(4) STABLE - 3+ 1.80065 64 19.9
11B 11.0093054(4) STABLE - 3/2- 2.688637 74.87 80.1
12B 12.0143521(15) 20.20(2) ms ß- to 12C; ß- + 3a to n 1+ 1.0031 78.29 -
13B 13.0177802(12) 17.33(17) ms ß- to 13C; ß- + n to 12C 3/2- 3.17778 83.58 -
14B 14.025404(23) 12.5(5) ms ß- to 14C; ß- + n to 13C 2- N/A 84.2 -
15B 15.031103(24) 9.87(7) ms ß- + n to 14C; ß- to 15C; ß- + 2n to 13C 3/2- N/A 86.69 -
16B 16.03981(6) <190E-12 s [<0.1 ] n to 15B 0- N/A 87.32 -
17B 17.04699(18) 5.08(5) ms ß- + n to 16C; ß- to 17C; ß- + 2n to 15C; ß- + 3n to 14C; ß- + 4n to 13C (3/2-) N/A 88.87 -
18B 18.05617(86)# >26 ns n to 17B (4-)# N/A 87.64 -
19B 19.06373(43)# 2.92(13) ms ß- to 19C (3/2-)# N/A 89.19 -