Boron facts for kids

Quick facts for kids
Boron, ₅B

boron (β-rhombohedral)
Boron
Pronunciation	/ˈbɔːrɒn/ ​(BOHR-on)
Allotropes	α-, β-rhombohedral, β-tetragonal (and more)
Appearance	black-brown
Standard atomic weight Ar, std(B)	[10.806, 10.821] conventional: 10.81
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
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	−5, −1, +1, +2, +3 (a mildly acidic oxide)
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
Spectral lines of boron
Other properties
Natural occurrence	primordial
Crystal structure	​rhombohedral
Speed of sound thin rod	16,200 m/s (at 20 °C)
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
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)
Main isotopes of boron
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 10B 20% stable 11B 80% stable
10B content may be as low as 19.1% and as high as 20.3% in natural samples. 11B is the remainder in such cases.

Boron in a tube

Boron is a special chemical element. Its chemical symbol is B. It has the atomic number 5. Boron is known as a metalloid. This means it has some properties like a metal and some like a non-metal.

You won't find pure boron by itself in nature. Instead, it's usually found in chemical compounds. A common place to find it is in a mineral called borax.

There are two main forms, or allotropes, of boron. One form is amorphous boron, which looks like a brown powder. The other is crystalline boron, which is black and very hard. This metallic form can conduct electricity, but not very well, especially at room temperature. Boron is the fifth element on the periodic table and is found in the Earth's crust.

What is Boron Used For?

Making Electronics Work Better

Pure boron is used in the semiconductor industry. It's added as a "dopant." A dopant is a tiny amount of a substance that changes how a semiconductor behaves with electricity. This helps make electronic devices work correctly.

Strong and Lightweight Materials

Boron compounds are very important for making strong materials that don't weigh much. This is useful in many areas, like building things that need to be both tough and light.

Safe Insecticides and Preservatives

Some boron compounds are used as non-toxic insecticides. This means they can kill insects without being harmful to people or pets. They are also used as preservatives to keep things from spoiling.

Creating New Chemicals

Boron compounds are also used in chemical synthesis. This is the process of making new chemical substances.

Boron and Living Things

Important for Plants

Plants need boron to grow and stay healthy. Even small amounts of boron are vital for their life processes.

Good for Animals

Animals, including humans, also need very small amounts of boron in their bodies. It helps keep them healthy, though scientists are still learning exactly how it works.

Discovery of Boron

Boron was first discovered by Sir Humphry Davy. He was an English chemist. He found it in the year 1808.

Boron's Properties

Boron needs a lot of heat to melt. It melts at 2075 °C (3767 °F). It boils at an even higher temperature, 4000 °C (7232 °F).

Images for kids

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  Sassolite is a mineral that contains boron.

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  Chunks of boron.

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  This is a model of a tetraborate anion, which is found in borax. The pink balls are boron atoms.

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  The structure of Boron (III) trifluoride.

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  Models showing the shapes of boron atoms in borane clusters.

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  A model of magnesium diboride, which is a superconductor. Boron atoms form layers.

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  This graph shows how boron interacts with neutrons.

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  A piece of ulexite, another mineral containing boron.

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  Crystals of borax.

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  Glassware made with borosilicate, a type of glass that uses boron.

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  The unit cell of B4C, a compound of boron and carbon.

See also

In Spanish: Boro para niños