Beryllium

General

Name	Beryllium	Symbol	Be
Atomic number	4	Atomic weight	9.01218
Density @ 293 K	1.848 g/cm3	Atomic volume	5.0 cm3/mol
Group	Alkali Earth	Discovered	1797

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States

State (s, l, g)	s
Melting point	1551.2 K	Boiling point	2773 K
Heat of fusion	12.20 kJ/mol	Heat of vaporization	292.40 kJ/mol

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Energies

1st ionization energy	899.4 kJ/mole	Electronegativity	1.57
2nd ionization energy	1757.1 kJ/mole	Electron affinity	kJ/mole
3rd ionization energy	14848.3 kJ/mole	Specific heat	1.82 J/gK
Heat atomization	324 kJ/mole atoms

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Oxidation & Electrons

Shells	2,2	Electron configuration	[He] 2s2
Minimum oxidation number	0	Maximum oxidation number	2
Minimum common oxidation number	0	Maximum common oxidation number	2

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Appearance & Characteristics

Structure	hcp: hexagonal close pkd	Color	steel gray
Uses	Cu alloys, X-ray windows	Toxicity	yes
Hardness	mohs	Characteristics	toxic

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Reactions

Reaction with air	vigorous, w/ht=>BeO,Be3N2	Reaction with 6M HCl	mild, =>H2
Reaction with 6M HCl	mild, =>H2	Reaction with 15M HNO3	none
Reaction with 6M NaOH	mild, =>H2, [Be(OH)4](2-)

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Other Forms

Number of isotopes		1	Hydride(s)		BeH2
Oxide(s)		BeO	Chloride(s)		BeCl2

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Radius

Ionic radius (2- ion)	pm	Ionic radius (1- ion)	pm
Atomic radius	112 pm	Ionic radius (1+ ion)	pm
Ionic radius (2+ ion)	59 pm	Ionic radius (3+ ion)	pm

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Conductivity

Thermal conductivity		201 J/m-sec-deg	Electrical conductivity		250 1/mohm-cm
Polarizability		5.6 A^3

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HOME

Source	Beryl (silicate)	Rel. abund. solar system	-0.137 log
Abundance earth's crust	0.4 log	Cost, pure	530 $/100g
Cost, bulk	59 $/100g

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History:

(Gr. beryllos, beryl; also called Glucinium or Glucinum, Gr. glykys, sweet) Discovered as the oxide by Vauquelin in beryl and in emeralds in 1798. The metal was isolated in 1828 by Wohler and by Bussy independently by the action of potassium on beryllium chloride. Beryllium is found in some 30 mineral species, the most important of which are bertrandite, beryl, chrysoberyl, and phenacite. Aquamarine and emerald are precious forms of beryl. Beryl and bertrandite are the most important commercial sources of the element and its compounds. Most of the metal is now prepared by reducing beryllium fluoride with magnesium metal. Beryllium metal did not become readily available to industry until 1957. The metal, steel gray in color, has many desirable properties. It is one of the lightest of all metals, and has one of the highest melting points of the light metals. Its modulus of elasticity is about one third greater than that of steel. It resists attack by concentrated nitric acid, has excellent thermal conductivity, and is nonmagnetic. It has a high permeability to X-rays and when bombarded by alpha particles, as from radium or polonium, neutrons are produced in the amount of about 30 neutrons/million alpha particles. At ordinary temperatures beryllium resists oxidation in air, although its ability to scratch glass is probably due to the formation of a thin layer of the oxide. Beryllium is used as an alloying agent in producing beryllium copper which is extensively used for springs, electrical contacts, spot-welding electrodes, and nonsparking tools. It has found application as a structural material for high-speed aircraft, missiles, spacecraft, and communication satellites. It is being used in the windshield frame, brake discs, support beams, and other structural components of the space shuttle. Because beryllium is relatively transparent to X-rays, ultra-thin Be-foil is finding use in X-ray lithography for reproduction of microminiature integrated circuits. Beryllium is used in nuclear reactors as a reflector or moderator for it has a low thermal neutron absorption cross section. It is used in gyroscopes, computer parts, and instruments where lightness, stiffness, and dimensional stability are required. The oxide has a very high melting po9int and is also used in nuclear work and ceramic applications. Beryllium and its salts are toxic and should be handled with the greatest of care. Beryllium and its compounds should not be tasted to verify the sweetish nature of beryllium (as did early experimenters). The metal, its alloys, and its salts can be handled if certain work codes are observed, but no attempt should be made to work with beryllium before becoming familiar with proper safeguards.

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