Boron

Boron (B)

Boron is the 5th element in the periodic table and has a symbol of B and atomic number of 5. It has an atomic weight of 10.810 and a mass number of 11. Boron has five protons and six neutrons in its nucleus, and five electrons in two shells. It is located in group thirteen, period two and block p of the periodic table. 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.
Atomic Number5
Atomic Weight10.81
Mass Number11
Group13
Period2
Blockp
Protons5 p+
Neutrons6 n0
Electrons5 e-
Animated Bohr Model of B (Boron)

Physical Properties

Atomic Radius
85 pm
Molar Volume
Covalent Radius
85 pm
Metallic Radius
80 pm
Ionic Radius
1 pm
Crystal Radius
15 pm
Van der Waals Radius
192 pm
Density
2.34 g/cm³
Atomic Radii of the Elements: Boron020406080100120140160180200pmAtomic RadiusCovalent RadiusMetallic RadiusVan der Waals Radius

Chemical Properties

Energy
Proton Affinity
Electron Affinity
0.279723 eV/particle
Ionization Energy
8.298019 eV/particle
Ionization Energies of B (Boron)
Heat of Vaporization
504.5 kJ/mol
Heat of Fusion
23.6 kJ/mol
Heat of Formation
565 kJ/mol
Electrons
Electron Shells2, 3
Bohr Model: B (Boron)
Valence Electrons3
Lewis Structure: B (Boron)
Electron Configuration[He] 2s2 2p1
1s2 2s2 2p1
Enhanced Bohr Model of B (Boron)
Orbital Diagram of B (Boron)
Oxidation States-5, -1, 0, 1, 2, 3
Electronegativity
2.04
Electrophilicity Index
1.1470276511768214 eV/particle
States of Matter
PhaseSolid
Gas Phase
Boiling Point
4,273.15 K
Melting Point
2,350.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual

Boron is a Black. B has a CPK of #00ff00, Jmol of #ffb5b5, and MOLCAS GV of #ffb5b5. The Appearance of Element 5 is black-brown.

Color
Black
Appearanceblack-brown
Refractive Index
Thermodynamic Properties
Thermal Conductivity
27.4 W/(m K)
Thermal Expansion
0.000006 1/K
Molar Heat Capacity
11.087 J/(mol K)
Specific Heat Capacity
1.026 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeInsulator
Electrical Conductivity
0.0000000001 MS/m
Electrical Resistivity
10,000 m Ω
Superconducting Point
Magnetism
Typediamagnetic
Magnetic Susceptibility (Mass)
-0.0000000087 m³/Kg
Magnetic Susceptibility (Molar)
-0.0000000000941 m³/mol
Magnetic Susceptibility (Volume)
-0.0000214
Magnetic Ordering
Curie Point
Neel Point
Structure

The Crystal Structure of Boron is TET. The lattice constant of B is 8.73 Å. The lattice angles of Element 5 are 1.01334, 1.01334, 1.01334.

Crystal StructureSimple Trigonal (TET)
Lattice Constant
8.73 Å
Lattice Angles1.01334, 1.01334, 1.01334
Mechanical Properties

Boron has a Mohs hardness of 9.3 MPa, and Vickers of 49000 MPa. The Bulk Modulus of B is 320 GPa. The Speed of Sound of Element 5 is 16200 m/s.

Hardness
9.3 MPa
Bulk Modulus
320 GPa
Shear Modulus
Young's Modulus
Poisson Ratio
Speed of Sound
16,200 m/s
Classification

The CAS Group of Boron is IIIB. The IUPAC Group of B is IIIA. The Glawe Number of Element 5 is 86. The Mendeleev Number of Boron (B) is 81. The Pettifor Number of Boron is 86. The Goldschmidt Class of B is litophile.

CategoryMetalloids, Metalloids
CAS GroupIIIB
IUPAC GroupIIIA
Glawe Number86
Mendeleev Number81
Pettifor Number86
Geochemical Class
Goldschmidt Classlitophile

Other

The Dipole Polarizability of Boron is 20.5 plus or minus 0.1 a₀. B has a C6 Dispersion Coefficient (CD) of 99.5 a₀, and C6 Dispersion Coefficient (GB) of 99.2 a₀. The Allotropes of Element 5 are Alpha Rhombohedral Boron, Beta Rhombohedral Boron, Alpha Tetragonal Boron. The Neutron Cross Section of Boron (B) is 760. The Neutron Mass Absorption of Boron is 2.4. The Quantum Numbers of B is 2P1/2. The Space Group of Element 5 is 166 (R_3m).

Gas Basicity
Dipole Polarizability
20.5 ± 0.1 a₀
C6 Dispersion Coefficient
99.5 a₀
AllotropesAlpha Rhombohedral Boron, Beta Rhombohedral Boron, Alpha Tetragonal Boron
Neutron Cross Section
760
Neutron Mass Absorption
2.4
Quantum Numbers2P1/2
Space Group166 (R_3m)

Isotopes of Boron

Stable Isotopes2
Unstable Isotopes14
Natural Isotopes2
Isotopic Composition1180.35%1180.35%1019.65%1019.65%

6B

Mass Number6
Neutron Number1
Relative Atomic Mass
6.0508 ± 0.00215 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin2
Quadrupole Moment
Discovery Year
Parity-

Decay ModeIntensity
2p (2-proton emission)

7B

Mass Number7
Neutron Number2
Relative Atomic Mass
7.029712 ± 0.000027 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
570 ± 14 ys
Spin3/2
Quadrupole Moment
Discovery Year1967
Parity-

Decay ModeIntensity
p (proton emission)100%

8B

Mass Number8
Neutron Number3
Relative Atomic Mass
8.024607315 ± 0.000001073 Da
G-Factor
0.51775 ± 0.00015
Abundance
Radioactivity☢️ Radioactive
Half Life
771.9 ± 0.9 ms
Spin2
Quadrupole Moment
0.0643 ± 0.0014
Discovery Year1950
Parity+

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+α (β+-delayed α emission)100%

9B

Mass Number9
Neutron Number4
Relative Atomic Mass
9.013329645 ± 0.000000969 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
800 ± 300 zs
Spin3/2
Quadrupole Moment
Discovery Year1940
Parity-

Decay ModeIntensity
p (proton emission)100%

10B

Mass Number10
Neutron Number5
Relative Atomic Mass
10.012936862 ± 0.000000016 Da
G-Factor
0.60015453333333 ± 0.00000026666666666667
Abundance
19.65 ± 0.44
RadioactivityStable
Half LifeNot Radioactive ☢️
Spin3
Quadrupole Moment
0.0846 ± 0.0002
Discovery Year1920
Parity+

11B

Mass Number11
Neutron Number6
Relative Atomic Mass
11.009305166 ± 0.000000013 Da
G-Factor
1.792252 ± 0.00000066666666666667
Abundance
80.35 ± 0.44
RadioactivityStable
Half LifeNot Radioactive ☢️
Spin3/2
Quadrupole Moment
0.04059 ± 0.0001
Discovery Year1920
Parity-

12B

Mass Number12
Neutron Number7
Relative Atomic Mass
12.014352638 ± 0.000001418 Da
G-Factor
1.003 ± 0.001
Abundance
Radioactivity☢️ Radioactive
Half Life
20.2 ± 0.02 ms
Spin1
Quadrupole Moment
0.0132 ± 0.0003
Discovery Year1935
Parity+

Decay ModeIntensity
β (β decay)100%
βα (β-delayed α emission)0.6%

13B

Mass Number13
Neutron Number8
Relative Atomic Mass
13.017779981 ± 0.000001073 Da
G-Factor
2.1185333333333 ± 0.00033333333333333
Abundance
Radioactivity☢️ Radioactive
Half Life
17.16 ± 0.18 ms
Spin3/2
Quadrupole Moment
0.0365 ± 0.0008
Discovery Year1956
Parity-

Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)0.266%

14B

Mass Number14
Neutron Number9
Relative Atomic Mass
14.02540401 ± 0.000022773 Da
G-Factor
0.5925 ± 0.0025
Abundance
Radioactivity☢️ Radioactive
Half Life
12.36 ± 0.29 ms
Spin2
Quadrupole Moment
0.0297 ± 0.0008
Discovery Year1966
Parity-

Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)6.04%
2n (2-neutron emission)

15B

Mass Number15
Neutron Number10
Relative Atomic Mass
15.031087023 ± 0.000022575 Da
G-Factor
1.7726666666667 ± 0.01
Abundance
Radioactivity☢️ Radioactive
Half Life
10.18 ± 0.35 ms
Spin3/2
Quadrupole Moment
0.0379 ± 0.0011
Discovery Year1966
Parity-

Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)98.7%
2n (2-neutron emission)1.5%

16B

Mass Number16
Neutron Number11
Relative Atomic Mass
16.039841045 ± 0.000026373 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin0
Quadrupole Moment
0
Discovery Year2000
Parity-

Decay ModeIntensity
n (neutron emission)

17B

Mass Number17
Neutron Number12
Relative Atomic Mass
17.046931399 ± 0.000219114 Da
G-Factor
1.7 ± 0.013333333333333
Abundance
Radioactivity☢️ Radioactive
Half Life
5.08 ± 0.05 ms
Spin3/2
Quadrupole Moment
0.0385 ± 0.0015
Discovery Year1973
Parity-

Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)63%
2n (2-neutron emission)12%
3n (3-neutron emission)3.5%
4n0.4%

18B

Mass Number18
Neutron Number13
Relative Atomic Mass
18.055601683 ± 0.00021918 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin2
Quadrupole Moment
Discovery Year2010
Parity-

Decay ModeIntensity
n (neutron emission)100%

19B

Mass Number19
Neutron Number14
Relative Atomic Mass
19.064166 ± 0.000564 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
2.92 ± 0.13 ms
Spin3/2
Quadrupole Moment
Discovery Year1984
Parity-

Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)71%
2n (2-neutron emission)17%
3n (3-neutron emission)9.1%

20B

Mass Number20
Neutron Number15
Relative Atomic Mass
20.074505644 ± 0.000586538 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin1
Quadrupole Moment
Discovery Year2018
Parity-

Decay ModeIntensity
n (neutron emission)100%
β n (β-delayed neutron emission)
2n (2-neutron emission)

21B

Mass Number21
Neutron Number16
Relative Atomic Mass
21.084147485 ± 0.00059975 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin3/2
Quadrupole Moment
Discovery Year2018
Parity-

Decay ModeIntensity
2n (2-neutron emission)100%
Boron
Electron shell 005 Boron

History

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. Boron was not recognized as an element until it was isolated in 1808 by Sir Humphry Davy and by Joseph Louis Gay-Lussac and Louis Jacques Thénard. Jöns Jakob Berzelius identified boron as an element in 1824. From the Arabic word Buraq, Persian Burah

DiscoverersSir H. Davy, J.L. Gay-Lussac, L.J. Thénard
Discovery LocationEngland/France
Discovery Year1808
Etymology (Name Origin)From Arabic and Persian words for borax.
PronunciationBO-ron (English)
Elemental boron, boron oxide, boric acid, borates and many organoboron compounds are non-toxic
Boron is an essential nutrient for all green plants

Uses

Boron oxide is used in glassmaking and ceramics. Borax is used in making fiberglass, as a cleansing fluid, a water softener, insecticide, herbicide and disinfectant. Boric acid is used as a mild antiseptic and as a flame retardant. Boron shielding is used as a control for nuclear reactors. Used with titanium & tungsten to make heat resistant alloys for jets & rockets.

Sources

Obtained from kernite, a kind of borax (Na2B4O7.10H2O). High purity boron is produced by electrolysis of molten potassium fluroborate and potassium chloride (KCl).

Abundance
Abundance in Earth's crust
Natural Abundance (Oceans)
4.44 mg/L
Natural Abundance (Human Body)
0.00007 %
Natural Abundance (Meteor)
0.00016 %
Natural Abundance (Sun)
0.0000002 %
Abundance in Universe
0.0000001 %

Nuclear Screening Constants

1s0.3205
2p2.5786
2s2.4238

Also Known As

  • B
  • element 5
  • 5B
  • boracium

Translations

  • Frenchbore
  • Italianboro
  • Norwegian Bokmålbor
  • GermanBor
  • Esperantoboro
  • Polishbor
  • Russianбор
  • Spanishboro
  • Dutchboor
  • Chinese (Traditional)
  • Gujaratiબોરોન
  • Hebrewבור
  • Afrikaansboor
  • Amharicቦሮን
  • AragoneseBoro
  • Arabicبورون
  • AsturianBoru
  • AzerbaijaniBor
  • BelarusianБор
  • Bulgarianбор
  • Banglaবোরন
  • BretonBor
  • Bosnianbor
  • Catalanbor
  • Central Kurdishبۆرۆن
  • CorsicanBoru
  • Czechbor
  • ChuvashБор
  • WelshBoron
  • Danishbor
  • Divehiބޯރޯން
  • Greekβόριο
  • Estonianboor
  • Basqueboro
  • Persianبور
  • Finnishboori
  • Northern FrisianBoor
  • FriulianBôr
  • Western FrisianBoar
  • IrishBórón
  • GagauzBor
  • Galicianboro
  • ManxBoron
  • Hakka ChinesePhìn
  • HawaiianBoron
  • Hindiबोरॉन
  • Fiji HindiBoron
  • Croatianbor
  • Hungarianbór
  • Armenianբոր
  • Interlinguaboro
  • Indonesianboron
  • Idoborono
  • Icelandicbór
  • Japaneseホウ素
  • Lojbanjicmrboro
  • JavaneseBoron
  • Georgianბორი
  • Kannadaಬೊರಾನ್
  • Korean붕소
  • KurdishBor
  • KomiБор
  • Latinborium
  • LuxembourgishBor
  • LigurianBoro
  • LingalaBolo
  • Lithuanianboras
  • Latvianbors
  • Māoripūtiwha
  • MacedonianБор
  • Malayalamബോറോൺ
  • Marathiबोरॉन
  • Western MariБор
  • Malayboron
  • Burmeseဘိုရွန်
  • nahXacoiztatl
  • Low GermanBor
  • Nepaliबोरोन
  • Newariबोरोन
  • Norwegian Nynorskbor
  • Novialbore
  • OccitanBòr
  • Punjabiਬੋਰਾਨ
  • PiedmonteseBòr
  • Western Panjabiبورون
  • Portugueseboro
  • QuechuaBoru
  • Romanianbor
  • Sanskritबोरान
  • Sicilianboru
  • Serbo-CroatianBor
  • Sinhalaබෝරෝන්
  • Slovakbór
  • Slovenianbor
  • AlbanianBori
  • Serbianбор
  • Saterland FrisianBor
  • Swedishbor
  • SwahiliBoroni
  • Tamilபோரன்
  • Teluguబోరాన్
  • TajikБор
  • Thaiโบรอน
  • TagalogBoron
  • Turkishbor
  • Uyghurبور
  • Ukrainianбор
  • UzbekBor
  • VepsBor
  • Vietnamesebo
  • WarayBoro
  • KalmykБорон
  • Yiddishבאר
  • YorubaBoron
  • Chinese
  • English (Canada)Boron
  • English (United Kingdom)boron
  • German (Switzerland)Bor
  • Portuguese (Brazil)boro
  • Cantonese
  • Belarusian (Taraskievica orthography)бор
  • CebuanoBoro
  • Odiaବୋରନ
  • Kazakhбор
  • TatarБор
  • Scotsboron
  • Chinese (China)
  • Chinese (Hong Kong SAR China)
  • Literary Chinese
  • SomaliBooron
  • ChechenБор
  • ErzyaБор
  • AromanianBoru
  • cdoBèng
  • LimburgishBoor
  • Scottish GaelicBòron
  • LombardBoro
  • Malteseboru
  • KikuyuBoron
  • KyrgyzБор
  • Min Nan ChinesePhêng-sò͘
  • Paliबोरोन
  • Mongolianбор
  • Bhojpuriबोरॉन
  • Tibetanཚ་ནག
  • SundaneseBoron
  • Lingua Franca Novaboro
  • Wu Chinese
  • Khmerបរ
  • oloBorum
  • kbpBɔrɩ
  • Jamaican Creole EnglishBuoran
  • Chinese (Taiwan)
  • Chinese (Simplified)
  • SardinianBoru
  • Santaliᱵᱳᱨᱚᱱ
  • Chinese (Singapore)
  • Chinese (Malaysia)
  • Chinese (Macao SAR China)
  • Moroccan Arabicبور
  • azbبور
  • Pashtoبورون
  • Assameseব'ৰণ
  • Egyptian Arabicبورون
  • BikolBoron
  • lldBor
  • CornishBoron
  • Manipuriꯕꯣꯔꯣꯟ
  • BalineseBoron
  • Malay (Arabic)بورون
  • ShonaBhawaraki
  • Urduبورون
  • Gan Chinese
  • FaroeseBor
  • blkဘိုရွန်
  • ZuluUmBohlwa
  • OromoBooroonii