B 5

Boron (B)

metalloid

Period: 2 Group: 13 Block: p

Solid

Standard Atomic Weight

Electron configuration

[He] 2s² 2p¹

Melting point

2074.85 °C (2348 K)

Boiling point

3999.85 °C (4273 K)

Density

2370 kg/m³

Oxidation states

−5, −1, 0, +1, +2, +3

Electronegativity (Pauling)

2.04

Ionization energy (1st)

Discovery year

1808

Atomic radius

85 pm

Details

Name origin From Arabic and Persian words for borax.

Discovery country England/France

Discoverers Sir H. Davy, J.L. Gay-Lussac, L.J. Thénard

Boron is a light metalloid in group 13, notable for electron-deficient bonding and a rich cluster chemistry. It occurs naturally only in compounds, mainly as borates in evaporite minerals and brines. Elemental boron is difficult to prepare in high purity and has several allotropes built from B₁₂ icosahedra. Technologically, boron is most important through borate minerals, borosilicate glass, detergents, ceramics, fertilizers, and neutron-absorbing materials.

An element of group 13 of the periodic table. There are two allotropes, amorphous boron is a brown power, but metallic boron is black. The metallic form is hard (9.3 on Mohs' scale) and a bad conductor in room temperatures. It is never found free in nature. Boron-10 is used in nuclear reactor control rods and shields. It was discovered in 1808 by Sir Humphry Davy and by J.L. Gay-Lussac and L.J. Thenard.

The name derives from the Arabic buraq for "white". Although its compounds were known for thousands of years, it was not isolated until 1808 by the French chemists Louis-Joseph Gay-Lussac and Louis-Jacques Thenard.

Boron was discovered by Joseph-Louis Gay-Lussac and Louis-Jaques Thénard, French chemists, and independently by Sir Humphry Davy, an English chemist, in 1808. They all isolated boron by combining boric acid (H3BO3) with potassium. Today, boron is obtained by heating borax (Na2B4O7·10H2O) with carbon, although other methods are used if high-purity boron is required.

From the Arabic word Buraq, Persian Burah. Boron compounds have been known for thousands of years, but the element was not discovered until 1808 by Sir Humphry Davy and by Gay-Lussac and Thenard.

Read about Boron on Wikipedia

Images

Properties

Physical

Atomic radius (empirical) 85 pm

Covalent radius 84 pm

Van der Waals radius 192 pm

Metallic radius 80 pm

Density

Molar volume 0.0046 L/mol

Phase at STP solid

Melting point 2074.85 °C

Boiling point 3999.85 °C

Thermal conductivity 27.4 W/(m·K)

Specific heat capacity 1.026 J/(g·K)

Molar heat capacity 11.087 J/(mol·K)

Crystal structure tetragonal

Chemical

Electronegativity (Pauling) 2.04

Electronegativity (Allen) 2.051

Electron affinity

Ionization energy (1st)

Ionization energy (2nd)

Ionization energy (3rd)

Ionization energy (4th)

Ionization energy (5th)

Oxidation states −5, −1, 0, +1, +2, +3

Valence electrons 3

Electron configuration

Electron configuration (semantic)

Thermodynamic

Heat of fusion 0.52028813 eV

Heat of vaporization 4.974867 eV

Heat of sublimation 5.855833 eV

Heat of atomization 5.855833 eV

Atomization enthalpy

Nuclear

Stable isotopes 2

Discovery year 1808

Abundance

Abundance (Earth's crust) 10 mg/kg

Abundance (ocean)

Reactivity

N/A

Crystal Structure

Lattice constant a 873 pm

Electronic Structure

Electrons per shell 2, 3

Identifiers

CAS number 7440-42-8

Term symbol

InChI InChI=1S/B

InChI Key ZOXJGFHDIHLPTG-UHFFFAOYSA-N

Electron Configuration Measured

Ion charge

Protons 5

Electrons 5

Charge Neutral

Configuration B: 2s² 2p¹

[He] 2s² 2p¹

1s² 2s² 2p¹

Orbital diagram

↑↓

2/2

↑↓

2/2

↑

1/6 1↑

Total electrons: 5 Unpaired: 1

Atomic model

Protons 5

Neutrons 6

Electrons 5

Mass number 11

Stability Stable

Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.

Schematic atomic model, not to scale.

Atomic Fingerprint

Emission / Absorption Spectrum

Emission Visible: 380–750 nm

Isotope Distribution

Mass number	Atomic mass (u)	Natural abundance	Half-life
10 Stable	10.01293695 ± 0.00000041	19.9000%	Stable
11 Stable	11.00930536 ± 0.00000045	80.1000%	Stable

Measured

Phase / State

Solid 25 °C (298.15 K)

Reason: 2049.8 °C below melting point (2074.85 °C)

Melting point 2074.85 °C

Boiling point 3999.85 °C

Below melting by 2049.8 °C

0 K Current temperature: 25 °C 6000 K

Phase timeline

Schematic, not to scale

Solid

Liquid

Gas

Melting

Boiling

25°C

Solid

Liquid

Gas

Current

Phase transition points

Melting point Literature

2074.85 °C

Boiling point Literature

3999.85 °C

Current phase Calculated
Solid

Transition energies

Heat of fusion Literature

0.52028813 eV

Energy required to melt 1 mol at melting point

Heat of vaporization Literature

4.974867 eV

Energy required to vaporize 1 mol at boiling point

Heat of sublimation Literature

5.855833 eV

Energy required to sublime 1 mol at sublimation point

Density

Reference density Literature

2370 kg/m³

At standard conditions

Current density Calculated

2370 kg/m³

At standard conditions

Atomic Spectra

Lines Holdings ?

Ion	Charge	Total lines	Transition probabilities	Level designations
B I	0	371	269	371
11B I Isotope	0	53	0	53
10B I Isotope	0	11	0	11
B II	+1	592	435	592
10B II Isotope	+1	9	0	9
11B II Isotope	+1	9	0	9
B III	+2	390	106	390
B IV	+3	478	234	478
B V	+4	258	240	258

NIST Lines Holdings →

Levels Holdings ?

Ion	Charge	Levels
B I	0	125
11B I Isotope	0	69
10B I Isotope	0	29
B II	+1	157
10B II Isotope	+1	10
11B II Isotope	+1	10
B III	+2	150
B IV	+3	174
B V	+4	101

NIST Levels Holdings →

5 B 10.8135

Boron — Atomic Orbital Visualizer

[He]2s22p1

Energy levels 2 3

Oxidation states -5, -1, 0, +1, +2, +3

HOMO 2p n=2 · l=1 · m=-1

Boron — Atomic Orbital Visualizer Preview

Three.js loads only on request

5 B 10.8135

Boron — Crystal Structure Visualizer

Trigonal · Pearson N/A

Experimental

Pearson N/A

Boron — Crystal Structure Visualizer Preview

Three.js loads only on request

Ionic Radii

Charge	Coordination	Spin	Radius
+3	3	N/A	1 pm
+3	4	N/A	11 pm
+3	6	N/A	27 pm

Compounds

10.810 u

10.013 u

11.009 u

B-

10.810 u

17.047 u

12.014 u

B-

10.013 u

13.018 u

B-

11.009 u

Isotopes (2)

	Mass number	Atomic mass (u)	Natural abundance	Half-life	Decay mode
	10 Stable	10.01293695 ± 0.00000041	19.9000% ± 0.7000%	Stable	stable
	11 Stable	11.00930536 ± 0.00000045	80.1000% ± 0.7000%	Stable	stable

10 Stable

Atomic mass (u) 10.01293695 ± 0.00000041

Natural abundance 19.9000% ± 0.7000%

Half-life Stable

Decay mode

stable

11 Stable

Atomic mass (u) 11.00930536 ± 0.00000045

Natural abundance 80.1000% ± 0.7000%

Half-life Stable

Decay mode

stable

Spectral Lines

Wavelength (nm)	Intensity	Ion stage	Type	Transition	Accuracy	Source
391.482 nm	N/A	B II	emission	1s2.2s.2p 1P* → 1s2.2p2 3P	Measured	NIST
391.687 nm	N/A	B II	emission	1s2.2s.2p 1P* → 1s2.2p2 3P	Measured	NIST
391.817 nm	N/A	B II	emission	1s2.2s.2p 1P* → 1s2.2p2 3P	Measured	NIST
394.447 nm	N/A	B II	emission	1s2.2p.3d 3F* → 1s2.2p.4f 3F	Measured	NIST
394.587 nm	N/A	B II	emission	1s2.2p.3d 3F* → 1s2.2p.4f 3F	Measured	NIST
394.82 nm	N/A	B II	emission	1s2.2p.3d 3F* → 1s2.2p.4f 3F	Measured	NIST
395.038 nm	18	B II	emission	1s2.2p.3d 1D* → 1s2.2p.4f 1F	Measured	NIST
395.1698 nm	N/A	B II	emission	1s2.2p2 1D → 1s2.2p2 1S	Measured	NIST
399.024 nm	70	B II	emission	1s2.2s.4p 1P* → 1s2.2s.8d 1D	Measured	NIST
400.017 nm	136	B III	emission	1s.2s.(3S).4d 4D → 1s.2s.(3S).5f 4F*	Measured	NIST
412.1928 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4f 3F*	Measured	NIST
412.1928 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4f 3F*	Measured	NIST
412.1928 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4f 3F*	Measured	NIST
412.1928 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4f 3F*	Measured	NIST
412.1928 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4f 3F*	Measured	NIST
412.1928 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4f 3F*	Measured	NIST
414.697 nm	N/A	B III	emission	1s2.5d 2D → 1s2.8f 2F*	Measured	NIST
414.708 nm	N/A	B III	emission	1s2.5d 2D → 1s2.8f 2F*	Measured	NIST
414.708 nm	N/A	B III	emission	1s2.5d 2D → 1s2.8f 2F*	Measured	NIST
415.284 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3P	Measured	NIST
415.284 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3P	Measured	NIST
415.471 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3P	Measured	NIST
415.471 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3P	Measured	NIST
415.471 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3P	Measured	NIST
415.584 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3P	Measured	NIST
417.896 nm	N/A	B I	emission	2s2.3p 2P* → 2s.2p2 2P	Measured	NIST
417.927 nm	N/A	B I	emission	2s2.3p 2P* → 2s.2p2 2P	Measured	NIST
418.099 nm	N/A	B I	emission	2s2.3p 2P* → 2s.2p2 2P	Measured	NIST
418.13 nm	N/A	B I	emission	2s2.3p 2P* → 2s.2p2 2P	Measured	NIST
419.4792 nm	180	B II	emission	1s2.2s.3p 1P* → 1s2.2s.4s 1S	Measured	NIST
419.773 nm	30	B IV	emission	1s.5s 3S → 1s.6p 3P*	Measured	NIST
424.3 nm	300	B III	emission	1s2.4p 2P* → 1s2.5d 2D	Measured	NIST
424.359 nm	N/A	B III	emission	1s2.4p 2P* → 1s2.5d 2D	Measured	NIST
424.37 nm	N/A	B III	emission	1s2.4p 2P* → 1s2.5d 2D	Measured	NIST
427.274 nm	50	B II	emission	1s2.2s.4s 3S → 1s2.2s.6p 3P*	Measured	NIST
429.571 nm	50	B II	emission	1s2.2s.4p 1P* → 1s2.2s.7d 1D	Measured	NIST
436.147 nm	60	B III	emission	1s.2p.(3P).4f 2F → 1s.2p.(3P).5g 2G*	Measured	NIST
436.61 nm	100	B III	emission	1s.2p.(3P).4f 4F → 1s.2p.(3P).5g 4G*	Measured	NIST
443.11 nm	N/A	B II	emission	1s2.2p.3d 3D* → 1s2.2p.4f 3F	Measured	NIST
443.185 nm	N/A	B II	emission	1s2.2p.3d 3D* → 1s2.2p.4f 3F	Measured	NIST
443.291 nm	N/A	B II	emission	1s2.2p.3d 3D* → 1s2.2p.4f 3F	Measured	NIST
445.943 nm	N/A	B IV	emission	1s.5p 3P* → 1s.6d 3D	Measured	NIST
445.943 nm	N/A	B IV	emission	1s.5p 3P* → 1s.6d 3D	Measured	NIST
445.943 nm	N/A	B IV	emission	1s.5p 3P* → 1s.6d 3D	Measured	NIST
447.112 nm	N/A	B III	emission	1s2.5s 2S → 1s2.7p 2P*	Measured	NIST
447.112 nm	N/A	B III	emission	1s2.5s 2S → 1s2.7p 2P*	Measured	NIST
447.2029 nm	N/A	B II	emission	1s2.2s.3p 3P* → 1s2.2s.4s 3S	Measured	NIST
447.2151 nm	N/A	B II	emission	1s2.2s.3p 3P* → 1s2.2s.4s 3S	Measured	NIST
447.2862 nm	470	B II	emission	1s2.2s.3p 3P* → 1s2.2s.4s 3S	Measured	NIST
448.692 nm	N/A	B III	emission	1s2.4d 2D → 1s2.5f 2F*	Measured	NIST
448.71 nm	N/A	B III	emission	1s2.4d 2D → 1s2.5f 2F*	Measured	NIST
449.09 nm	20	B IV	emission	1s.2s 1S → 1s.2p 1P*	Measured	NIST
449.773 nm	1700	B III	emission	1s2.4f 2F* → 1s2.5g 2G	Measured	NIST
449.853 nm	N/A	B III	emission	1s2.4f 2F* → 1s2.5f 2F*	Measured	NIST
449.859 nm	N/A	B III	emission	1s2.4f 2F* → 1s2.5f 2F*	Measured	NIST
450.481 nm	N/A	B III	emission	1s2.4f 2F* → 1s2.5d 2D	Measured	NIST
450.482 nm	N/A	B III	emission	1s2.4f 2F* → 1s2.5d 2D	Measured	NIST
451.9912773 nm	N/A	B V	emission	7i 2I → 9k 2K*	Measured	NIST
451.9946377 nm	N/A	B V	emission	7i 2I → 9k 2K*	Measured	NIST
453.229 nm	N/A	B II	emission	1s2.2s.4f 1F* → 1s2.2p.3p 1D	Measured	NIST
459.72 nm	N/A	B III	emission	1s.2s.(3S).4d 4D → 1s.2s.(3S).5p 4P*	Measured	NIST
459.73 nm	N/A	B III	emission	1s.2p.(3P).4p 4P → 1s.2p.(3P).5s 4P*	Measured	NIST
461.114 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3S	Measured	NIST
461.114 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3S	Measured	NIST
461.114 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2p.3p 3S	Measured	NIST
461.32 nm	N/A	B IV	emission	1s.5d 3D → 1s.6p 1P*	Measured	NIST
463.217 nm	N/A	B III	emission	1s2.4d 2D → 1s2.5p 2P*	Measured	NIST
463.243 nm	N/A	B III	emission	1s2.4d 2D → 1s2.5p 2P*	Measured	NIST
463.263 nm	N/A	B III	emission	1s2.4d 2D → 1s2.5p 2P*	Measured	NIST
464.69 nm	N/A	B IV	emission	1s.5d 3D → 1s.6f 1F*	Measured	NIST
464.69 nm	N/A	B IV	emission	1s.5d 3D → 1s.6f 1F*	Measured	NIST
464.701 nm	N/A	B IV	emission	1s.5d 3D → 1s.6f 3F*	Measured	NIST
464.701 nm	N/A	B IV	emission	1s.5d 3D → 1s.6f 3F*	Measured	NIST
464.701 nm	N/A	B IV	emission	1s.5d 3D → 1s.6f 3F*	Measured	NIST
464.701 nm	N/A	B IV	emission	1s.5d 3D → 1s.6f 3F*	Measured	NIST
464.701 nm	N/A	B IV	emission	1s.5d 3D → 1s.6f 3F*	Measured	NIST
464.701 nm	N/A	B IV	emission	1s.5d 3D → 1s.6f 3F*	Measured	NIST
465.58 nm	N/A	B IV	emission	1s.5d 1D → 1s.6f 1F*	Measured	NIST
465.786 nm	N/A	B IV	emission	1s.5f 3F* → 1s.6g 3G	Measured	NIST
465.786 nm	N/A	B IV	emission	1s.5f 3F* → 1s.6g 3G	Measured	NIST
465.786 nm	N/A	B IV	emission	1s.5f 3F* → 1s.6g 3G	Measured	NIST
465.8 nm	N/A	B IV	emission	1s.5f 1F* → 1s.6g 3G	Measured	NIST
465.815 nm	N/A	B IV	emission	1s.5g 3G → 1s.6h 3H*	Measured	NIST
465.815 nm	N/A	B IV	emission	1s.5g 3G → 1s.6h 3H*	Measured	NIST
465.815 nm	N/A	B IV	emission	1s.5g 3G → 1s.6h 3H*	Measured	NIST
465.815 nm	N/A	B IV	emission	1s.5g 1G → 1s.6h 3H*	Measured	NIST
465.92 nm	N/A	B IV	emission	1s.5g 1G → 1s.6f 1F*	Measured	NIST
465.92 nm	N/A	B IV	emission	1s.5g 3G → 1s.6f 1F*	Measured	NIST
465.92 nm	N/A	B IV	emission	1s.5g 3G → 1s.6f 1F*	Measured	NIST
465.927 nm	N/A	B IV	emission	1s.5g 3G → 1s.6f 3F*	Measured	NIST
465.927 nm	N/A	B IV	emission	1s.5g 3G → 1s.6f 3F*	Measured	NIST
465.927 nm	N/A	B IV	emission	1s.5g 3G → 1s.6f 3F*	Measured	NIST
465.927 nm	N/A	B IV	emission	1s.5g 1G → 1s.6f 3F*	Measured	NIST
468.31 nm	N/A	B IV	emission	1s.5p 1P* → 1s.6p 1P*	Measured	NIST
468.481 nm	N/A	B IV	emission	1s.6g 3G → 1s.8h 3H*	Measured	NIST
468.489 nm	N/A	B IV	emission	1s.6f 3F* → 1s.8g 3G	Measured	NIST
468.489 nm	N/A	B IV	emission	1s.6f 3F* → 1s.8g 3G	Measured	NIST
468.489 nm	N/A	B IV	emission	1s.6f 3F* → 1s.8g 3G	Measured	NIST
468.5 nm	N/A	B IV	emission	1s.6h 3H* → 1s.8i 3I	Measured	NIST
471.612 nm	15	B II	emission	1s2.2p.3d 1D* → 1s2.2p.4p 1P	Measured	NIST
471.99 nm	N/A	B IV	emission	1s.5p 1P* → 1s.6d 1D	Measured	NIST
477.384 nm	N/A	B IV	emission	1s.5d 3D → 1s.6p 3P*	Measured	NIST
477.384 nm	N/A	B IV	emission	1s.5d 3D → 1s.6p 3P*	Measured	NIST
477.384 nm	N/A	B IV	emission	1s.5d 3D → 1s.6p 3P*	Measured	NIST
478.42 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4p 3P*	Measured	NIST
478.42 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4p 3P*	Measured	NIST
478.4203 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4p 3P*	Measured	NIST
478.4203 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4p 3P*	Measured	NIST
478.4203 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4p 3P*	Measured	NIST
478.4203 nm	N/A	B II	emission	1s2.2s.3d 3D → 1s2.2s.4p 3P*	Measured	NIST
481.276 nm	N/A	B IV	emission	1s.5p 3P* → 1s.6s 3S	Measured	NIST
481.276 nm	N/A	B IV	emission	1s.5p 3P* → 1s.6s 3S	Measured	NIST
481.276 nm	N/A	B IV	emission	1s.5p 3P* → 1s.6s 3S	Measured	NIST
491.746 nm	500	B III	emission	1s2.4p 2P* → 1s2.5s 2S	Measured	NIST
491.84 nm	500	B III	emission	1s2.4p 2P* → 1s2.5s 2S	Measured	NIST
494.0365 nm	440	B II	emission	1s2.2s.3d 1D → 1s2.2s.4f 1F*	Measured	NIST
494.4788284 nm	N/A	B V	emission	6h 2H* → 7i 2I	Measured	NIST
494.4864305 nm	N/A	B V	emission	6h 2H* → 7i 2I	Measured	NIST
498.848 nm	N/A	B III	emission	1s2.5p 2P* → 1s2.7d 2D	Measured	NIST
498.901 nm	N/A	B III	emission	1s2.5p 2P* → 1s2.7d 2D	Measured	NIST
512.579 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.7f 3F*	Measured	NIST
512.579 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.7f 3F*	Measured	NIST
512.579 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.7f 3F*	Measured	NIST
515.776 nm	N/A	B III	emission	1s2.5d 2D → 1s2.7f 2F*	Measured	NIST
515.793 nm	N/A	B III	emission	1s2.5d 2D → 1s2.7f 2F*	Measured	NIST
516.57 nm	N/A	B III	emission	1s2.5f 2F* → 1s2.7g 2G	Measured	NIST
516.579 nm	N/A	B III	emission	1s2.5f 2F* → 1s2.7g 2G	Measured	NIST
522.65 nm	N/A	B III	emission	1s2.5d 2D → 1s2.7p 2P*	Measured	NIST
522.65 nm	N/A	B III	emission	1s2.5d 2D → 1s2.7p 2P*	Measured	NIST
522.667 nm	N/A	B III	emission	1s2.5d 2D → 1s2.7p 2P*	Measured	NIST
526.311 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2s.7g 3G	Measured	NIST
526.311 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2s.7g 3G	Measured	NIST
526.311 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2s.7g 3G	Measured	NIST
529.28 nm	N/A	B III	emission	1s2.5p 2P* → 1s2.7s 2S	Measured	NIST
529.34 nm	N/A	B III	emission	1s2.5p 2P* → 1s2.7s 2S	Measured	NIST
534.765 nm	15	B II	emission	1s2.2s.4s 1S → 1s2.2p.3s 1P*	Measured	NIST
539.322 nm	30	B II	emission	1s2.2s.4p 1P* → 1s2.2p.3p 1P	Measured	NIST
550.4527 nm	N/A	B I	emission	2s.2p2 2D → 2s2.11f 2F*	Measured	NIST
550.4622 nm	N/A	B I	emission	2s.2p2 2D → 2s2.11f 2F*	Measured	NIST
556.3146 nm	N/A	B I	emission	2s.2p2 2D → 2s2.10f 2F*	Measured	NIST
556.3244 nm	N/A	B I	emission	2s.2p2 2D → 2s2.10f 2F*	Measured	NIST
563.30717 nm	N/A	B I	emission	2s2.3s 2S → 2s2.4p 2P*	Measured	NIST
563.32732 nm	N/A	B I	emission	2s2.3s 2S → 2s2.4p 2P*	Measured	NIST
564.4278 nm	N/A	B I	emission	2s.2p2 2D → 2s2.9f 2F*	Measured	NIST
564.4379 nm	N/A	B I	emission	2s.2p2 2D → 2s2.9f 2F*	Measured	NIST
576.1901 nm	N/A	B I	emission	2s.2p2 2D → 2s2.8f 2F*	Measured	NIST
576.1901 nm	N/A	B I	emission	2s.2p2 2D → 2s2.8f 2F*	Measured	NIST
576.2006 nm	N/A	B I	emission	2s.2p2 2D → 2s2.8f 2F*	Measured	NIST
578.747 nm	N/A	B II	emission	1s2.2s.4s 3S → 1s2.2s.5p 3P*	Measured	NIST
578.747 nm	N/A	B II	emission	1s2.2s.4s 3S → 1s2.2s.5p 3P*	Measured	NIST
578.747 nm	N/A	B II	emission	1s2.2s.4s 3S → 1s2.2s.5p 3P*	Measured	NIST
581.833 nm	60	B I	emission	2s.2p2 2P → 2s.2p.(3P).3d 2D	Measured	NIST
582.116 nm	100	B I	emission	2s.2p2 2P → 2s.2p.(3P).3d 2D	Measured	NIST
582.228 nm	10	B I	emission	2s.2p2 2P → 2s.2p.(3P).3d 2D	Measured	NIST
594.2619 nm	N/A	B I	emission	2s.2p2 2D → 2s2.7f 2F*	Measured	NIST
594.2619 nm	N/A	B I	emission	2s.2p2 2D → 2s2.7f 2F*	Measured	NIST
594.2731 nm	N/A	B I	emission	2s.2p2 2D → 2s2.7f 2F*	Measured	NIST
601.35 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2s.6s 3S	Measured	NIST
601.35 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2s.6s 3S	Measured	NIST
601.35 nm	N/A	B II	emission	1s2.2s.4p 3P* → 1s2.2s.6s 3S	Measured	NIST
602.772 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.8d 2D	Measured	NIST
602.837 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.8d 2D	Measured	NIST
602.837 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.8d 2D	Measured	NIST
608.039 nm	85	B II	emission	1s2.2p2 1S → 1s2.2s.3p 1P*	Measured	NIST
612.224 nm	N/A	B II	emission	1s2.2p2 1S → 1s2.2s.3p 3P*	Measured	NIST
612.508 nm	93	B III	emission	1s.2s.(3S).3s 4S → 1s.2s.(3S).3p 4P*	Measured	NIST
612.752 nm	N/A	B III	emission	1s.2s.(3S).3s 4S → 1s.2s.(3S).3p 4P*	Measured	NIST
612.797 nm	N/A	B III	emission	1s.2s.(3S).3s 4S → 1s.2s.(3S).3p 4P*	Measured	NIST
614.891 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.6f 3F*	Measured	NIST
614.891 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.6f 3F*	Measured	NIST
614.891 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.6f 3F*	Measured	NIST
614.891 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.6f 3F*	Measured	NIST
614.891 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.6f 3F*	Measured	NIST
614.891 nm	N/A	B II	emission	1s2.2s.4d 3D → 1s2.2s.6f 3F*	Measured	NIST
617.867 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.8s 2S	Measured	NIST
617.936 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.8s 2S	Measured	NIST
618.638 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2p.3p 3D	Measured	NIST
618.638 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2p.3p 3D	Measured	NIST
618.638 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2p.3p 3D	Measured	NIST
619.359 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2p.3p 3D	Measured	NIST
619.359 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2p.3p 3D	Measured	NIST
619.735 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2p.3p 3D	Measured	NIST
622.745 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.7d 2D	Measured	NIST
622.815 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.7d 2D	Measured	NIST
622.815 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.7d 2D	Measured	NIST
624.4557 nm	N/A	B I	emission	2s.2p2 2D → 2s2.6f 2F*	Measured	NIST
624.4557 nm	N/A	B I	emission	2s.2p2 2D → 2s2.6f 2F*	Measured	NIST
624.4681 nm	N/A	B I	emission	2s.2p2 2D → 2s2.6f 2F*	Measured	NIST
628.551 nm	30	B II	emission	1s2.2s.3d 1D → 1s2.2s.4p 1P*	Measured	NIST
634.927 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2s.6g 3G	Measured	NIST
634.927 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2s.6g 3G	Measured	NIST
634.927 nm	N/A	B II	emission	1s2.2s.4f 3F* → 1s2.2s.6g 3G	Measured	NIST
635.676 nm	1	B II	emission	1s2.2s.4f 1F* → 1s2.2s.6g 1G	Measured	NIST
643.151 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.7s 2S	Measured	NIST
643.225 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.7s 2S	Measured	NIST
652.056 nm	N/A	B II	emission	1s2.2s.4s 3S → 1s2.2p.3s 3P*	Measured	NIST
652.959 nm	N/A	B II	emission	1s2.2s.4s 3S → 1s2.2p.3s 3P*	Measured	NIST
653.371 nm	N/A	B II	emission	1s2.2s.4s 3S → 1s2.2p.3s 3P*	Measured	NIST
656.269 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.6d 2D	Measured	NIST
656.345 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.6d 2D	Measured	NIST
656.345 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.6d 2D	Measured	NIST
657.112 nm	0.5	B II	emission	1s2.2s.5p 1P* → 1s2.2p.3p 1D	Measured	NIST
671.765 nm	0.5	B II	emission	1s2.2s.4d 1D → 1s2.2s.6f 1F*	Measured	NIST
677.866 nm	N/A	B I	emission	2s2.4p 2P* → 2s.2p2 2P	Measured	NIST
677.895 nm	N/A	B I	emission	2s2.4p 2P* → 2s.2p2 2P	Measured	NIST
678.401 nm	N/A	B I	emission	2s2.4p 2P* → 2s.2p2 2P	Measured	NIST
678.431 nm	N/A	B I	emission	2s2.4p 2P* → 2s.2p2 2P	Measured	NIST
678.614 nm	0.5	B II	emission	1s2.2s.4p 1P* → 1s2.2s.5d 1D	Measured	NIST
681.95167 nm	N/A	B I	emission	2s.2p2 2D → 2s2.5f 2F*	Measured	NIST
681.95167 nm	N/A	B I	emission	2s.2p2 2D → 2s2.5f 2F*	Measured	NIST
681.96637 nm	N/A	B I	emission	2s.2p2 2D → 2s2.5f 2F*	Measured	NIST
697.688 nm	N/A	B II	emission	1s2.2s.3s 3S → 1s2.2s.3p 1P*	Measured	NIST
703.027 nm	4	B II	emission	1s2.2s.3s 3S → 1s2.2s.3p 3P*	Measured	NIST
703.203 nm	3	B II	emission	1s2.2s.3s 3S → 1s2.2s.3p 3P*	Measured	NIST
703.233 nm	2	B II	emission	1s2.2s.3s 3S → 1s2.2s.3p 3P*	Measured	NIST
715.955 nm	N/A	B II	emission	1s2.2p.3s 3P* → 1s2.2p.3p 3P	Measured	NIST
716.016 nm	N/A	B II	emission	1s2.2p.3s 3P* → 1s2.2p.3p 3P	Measured	NIST
716.511 nm	N/A	B II	emission	1s2.2p.3s 3P* → 1s2.2p.3p 3P	Measured	NIST
716.846 nm	N/A	B II	emission	1s2.2p.3s 3P* → 1s2.2p.3p 3P	Measured	NIST
717.045 nm	N/A	B II	emission	1s2.2p.3s 3P* → 1s2.2p.3p 3P	Measured	NIST
717.602 nm	N/A	B II	emission	1s2.2p.3s 3P* → 1s2.2p.3p 3P	Measured	NIST
720.593 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.5d 2D	Measured	NIST
720.685 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.5d 2D	Measured	NIST
720.685 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.5d 2D	Measured	NIST
720.766 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.6s 2S	Measured	NIST
720.859 nm	N/A	B I	emission	2s2.3p 2P* → 2s2.6s 2S	Measured	NIST
722.85 nm	N/A	B II	emission	1s2.2s.4s 1S → 1s2.2s.5p 1P*	Measured	NIST

Extended Properties

Covalent Radii (Extended)

Covalent radius (Pyykkö)

Covalent radius (Pyykkö, double)

Covalent radius (Pyykkö, triple)

Van der Waals Radii

Truhlar

Batsanov

Alvarez

UFF

MM3

Dreiding

Atomic & Metallic Radii

Atomic radius (Rahm)

Metallic radius (C12)

Numbering Scales

Mendeleev

Pettifor

Glawe

Electronegativity Scales

Ghosh

Miedema

Gunnarsson–Lundqvist

Robles–Bartolotti

Polarizability & Dispersion

Dipole polarizability

Dipole polarizability (unc.)

C₆

C₆ (Gould–Bučko)

Miedema Parameters

Miedema molar volume

Miedema electron density

Supply Risk & Economics

Production concentration

Relative supply risk

Political stability (top producer)

Political stability (top reserve)

Phase Transitions & Allotropes

Melting point	2350.15 K
Boiling point	4273.15 K

Oxidation State Categories

−5 extended

+2 extended

+3 main

0 extended

−1 extended

+1 extended

Advanced Reference Data

Screening Constants (3)

n	Orbital	σ
1	s	0.3205
2	p	2.5786
2	s	2.4238

Crystal Radii Detail (3)

Charge	CN	r_crystal (pm)	Origin
3	III	15
3	IV	25
3	VI	41	calculated,

Isotope Decay Modes (30)

Isotope	Mode	Intensity
6	2p	—
7	p	100%
8	B+	100%
8	B+A	100%
9	p	100%
12	B-	100%
12	B-A	0.6%
13	B-	100%
13	B-n	0.3%
14	B-	100%

X‑ray Scattering Factors (502)

Energy (eV)	f₁	f₂
10	—	1.48933
10.1617	—	1.48084
10.3261	—	1.4724
10.4931	—	1.46401
10.6628	—	1.45567
10.8353	—	1.44738
11.0106	—	1.43913
11.1886	—	1.43093
11.3696	—	1.42278
11.5535	—	1.41467

Additional Data

Estimated Crustal Abundance

The estimated element abundance in the earth's crust.

1.0×101 milligrams per kilogram

References (1)

[5] Boron https://education.jlab.org/itselemental/ele005.html

Estimated Oceanic Abundance

The estimated element abundance in the earth's oceans.

4.44 milligrams per liter

References (1)

[5] Boron https://education.jlab.org/itselemental/ele005.html

Sources

Sources of this element.

The element is not found free in nature, but occurs as orthoboric acid usually found in certain volcanic spring waters and as borates in boron and colemantie.

Important sources of boron are ore rasorite (kernite) and tincal (borax ore). Both of these ores are found in the Mojave Desert. Tincal is the most important source of boron from the Mojave. Extensive borax deposits are also found in Turkey.

Boron exists naturally as 19.78% 10B isotope and 80.22% 11B isotope. High-purity crystalline boron may be prepared by the vapor phase reduction of boron trichloride or tribromide with hydrogen on electrically heated filaments. The impure or amorphous, boron, a brownish-black powder, can be obtained by heating the trioxide with magnesium powder.

Boron of 99.9999% purity has been produced and is available commercially. Elemental boron has an energy band gap of 1.50 to 1.56 eV, which is higher than that of either silicon or germanium.

References (1)

[6] Boron https://periodic.lanl.gov/5.shtml

References

(9)

1 PubChem

Data deposited in or computed by PubChem

Visit source

2 Atomic Mass Data Center (AMDC), International Atomic Energy Agency (IAEA)

The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.

Visit source License

3 IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW)

Boron

Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.

Visit source License

4 IUPAC Periodic Table of the Elements and Isotopes (IPTEI)

The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.

Visit source License

License note: Copyright (c) 2020 International Union of Pure and Applied Chemistry. The International Union of Pure and Applied Chemistry (IUPAC) contribution within Pubchem is provided under a CC-BY-NC-ND 4.0 license, unless otherwise stated.

5 Jefferson Lab, U.S. Department of Energy

Boron

Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/

Visit source License

License note: Please see citation and linking information: https://education.jlab.org/faq/index.html

6 Los Alamos National Laboratory, U.S. Department of Energy

Boron

The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.

Visit source License

7 NIST Physical Measurement Laboratory

Boron

The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database

Visit source License

8 PubChem Elements

Boron

This section provides all form of data related to element Boron.

License

9 PubChem Elements

Boron

The element property data was retrieved from publications.

License

Last updated: May 1, 2026

Data verified: May 12, 2026

Content is reviewed against latest scientific data.