Template:Infobox boron

Boron, ₅B

File:Boron R105.jpg boron (β-rhombohedral)
Boron
Pronunciation	/ˈbɔːrɒn/ ​(BOR-on)
Allotropes	α-, β-rhombohedral, β-tetragonal (and more)
Appearance	black-brown
Standard atomic weight Ar°(B)
	[10.806, 10.821] 10.81±0.02 (abridged)
Boron in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson – ↑ B ↓ Al beryllium ← boron → carbon
Atomic number (Z)	5
Group	group 13 (boron group)
Period	period 2
Block	p-block
Electron configuration	[He] 2s2 2p1
Electrons per shell	2, 3
Physical properties
Phase at STP	solid
Melting point	2349 K ​(2076 °C, ​3769 °F)
Boiling point	4200 K ​(3927 °C, ​7101 °F)
Density when liquid (at m.p.)	2.08 g/cm3
Heat of fusion	50.2 kJ/mol
Heat of vaporization	508 kJ/mol
Molar heat capacity	11.087 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 2348 2562 2822 3141 3545 4072
Atomic properties
Oxidation states	common: +3 −5, −1, 0, +1, +2
Electronegativity	Pauling scale: 2.04
Ionization energies	1st: 800.6 kJ/mol 2nd: 2427.1 kJ/mol 3rd: 3659.7 kJ/mol (more)
Atomic radius	empirical: 90 pm
Covalent radius	84±3 pm
Van der Waals radius	192 pm
Color lines in a spectral range Spectral lines of boron
Other properties
Natural occurrence	primordial
Crystal structure	​rhombohedral Rhombohedral crystal structure for boron
Thermal expansion	β form: 5–7 µm/(m⋅K) (at 25 °C)
Thermal conductivity	27.4 W/(m⋅K)
Electrical resistivity	~106 Ω⋅m (at 20 °C)
Magnetic ordering	diamagnetic
Molar magnetic susceptibility	−6.7×10−6 cm3/mol
Speed of sound thin rod	16,200 m/s (at 20 °C)
Mohs hardness	~9.5
CAS Number	7440-42-8
History
Discovery	Joseph Louis Gay-Lussac and Louis Jacques Thénard (30 June 1808)
First isolation	Humphry Davy (9 July 1808)
Isotopes of boron
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 8B synth 771.9 ms β+ 8Be 10B [18.9%, 20.4%] stable 11B [79.6%, 81.1%] stable

B · Boron
Be ← ibox Be	iso 5 B  [] IB-B [] IBisos []	→ C ibox C
File:Symbol category class.svg cat:B (0) File:Symbol category class.svg cat:B-isotopes (0) File:Commons-logo.svg Commons File:Wikidata-logo.svg Wikidata:Q618 File:Wiktionary-logo.svg Wiktionary
indexes by PT (page)

child table, as reused in {IB-B}
Main isotopes of boron
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 8B synth 771.9 ms β+ 8Be 10B [18.9%, 20.4%] stable 11B [79.6%, 81.1%] stable

Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)	caption: alt:
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
most stable isotope
File:Notification-icon-Wikidata-logo.svg Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01) See also {{Index of data sets}} · Cat:data sets (0) · (this table: )

References

These references will appear in the article, but this list appears only on this page.

Five of these are named references. They may be cited in the containing article as

• <ref name="v1" /> for the source Infrared Emission Spectroscopy of BF and AIF
• <ref name="magnet" /> for the source from Handbook of Chemistry and Physics
• <ref name="NISTic" /> for the source Atomic Weights and Isotopic Compositions for All Elements
• <ref name="Lussac" /> for the source by Gay-Lussac
• <ref name="Davy" /> for the source by Davy