Beryllium

Beryllium, ₄Be

Beryllium
Pronunciation	/bəˈrɪliəm/ ​(bə-RIL-ee-əm)
Appearance	white-gray metallic
Standard atomic weight Ar°(Be)
	9.0121831±0.0000005[1] 9.0122±0.0001 (abridged)[2]
Beryllium 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 – ↑ Be ↓ Mg lithium ← beryllium → boron
Atomic number (Z)	4
Group	group 2 (alkaline earth metals)
Period	period 2
Block	s-block
Electron configuration	[He] 2s2
Electrons per shell	2, 2
Physical properties
Phase at STP	solid
Melting point	1560 K ​(1287 °C, ​2349 °F)
Boiling point	2742 K ​(2469 °C, ​4476 °F)
Density (at 20° C)	1.845 g/cm3[3]
when liquid (at m.p.)	1.690 g/cm3
Critical point	5205 K,  MPa (extrapolated)
Heat of fusion	12.2 kJ/mol
Heat of vaporization	292 kJ/mol
Molar heat capacity	16.443 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1462 1608 1791 2023 2327 2742
Atomic properties
Oxidation states	0,[4] +1,[5] +2 (an amphoteric oxide)
Electronegativity	Pauling scale: 1.57
Ionization energies	1st: 899.5 kJ/mol 2nd: 1757.1 kJ/mol 3rd: 14,848.7 kJ/mol (more)
Atomic radius	empirical: 112 pm
Covalent radius	96±3 pm
Van der Waals radius	153 pm
Spectral lines of beryllium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp) (hP2)
Lattice constants	a = 228.60 pm c = 358.42 pm (at 20 °C)[3]
Thermal expansion	10.98×10−6/K (at 20 °C)[3][a]
Thermal conductivity	200 W/(m⋅K)
Electrical resistivity	36 nΩ⋅m (at 20 °C)
Magnetic ordering	diamagnetic
Molar magnetic susceptibility	−9.0×10−6 cm3/mol[6]
Young's modulus	287 GPa
Shear modulus	132 GPa
Bulk modulus	130 GPa
Speed of sound thin rod	12,890 m/s (at r.t.)[7]
Poisson ratio	0.032
Mohs hardness	5.5
Vickers hardness	1670 MPa
Brinell hardness	590–1320 MPa
CAS Number	7440-41-7
History
Discovery	Louis Nicolas Vauquelin (1798)
First isolation	Friedrich Wöhler & Antoine Bussy (1828)
Isotopes of beryllium v e
Main isotopes[8] Decay abun­dance half-life (t1/2) mode pro­duct 7Be trace 53.22 d ε 7Li 8Be synth 81.9 as α 4He 9Be 100% stable 10Be trace 1.387×106 y β− 10B
Category: Beryllium view talk edit | references

Beryllium is a chemical element; it has symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form minerals. Gemstones high in beryllium include beryl (aquamarine, emerald, red beryl) and chrysoberyl. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, beryllium is depleted as it is fused into heavier elements. Beryllium constitutes about 0.0004 percent by mass of Earth's crust. The world's annual beryllium production of 220 tons is usually manufactured by extraction from the mineral beryl, a difficult process because beryllium bonds strongly to oxygen.

In structural applications, the combination of high flexural rigidity, thermal stability, thermal conductivity and low density (1.85 times that of water) make beryllium metal a desirable aerospace material for aircraft components, missiles, spacecraft, and satellites.^[9] Because of its low density and atomic mass, beryllium is relatively transparent to X-rays and other forms of ionizing radiation; therefore, it is the most common window material for X-ray equipment and components of particle detectors.^[9] When added as an alloying element to aluminium, copper (notably the alloy beryllium copper), iron, or nickel, beryllium improves many physical properties.^[9] For example, tools and components made of beryllium copper alloys are strong and hard and do not create sparks when they strike a steel surface. In air, the surface of beryllium oxidizes readily at room temperature to form a passivation layer 1–10 nm thick that protects it from further oxidation and corrosion.^{[citation needed]} The metal oxidizes in bulk (beyond the passivation layer) when heated above 500 °C (932 °F), and burns brilliantly when heated to about 2,500 °C (4,530 °F).^{[citation needed]}

The commercial use of beryllium requires the use of appropriate dust control equipment and industrial controls at all times because of the toxicity of inhaled beryllium-containing dusts that can cause a chronic life-threatening allergic disease, berylliosis, in some people.^[10] Berylliosis causes pneumonia and other associated respiratory illness.

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