Atomic number: 4
Atomic weight: 9.012182 (3)

Standard state: solid at 298 K

Colour: lead grey
Classification: Metallic

Group name: Alkaline earth metal

Group in periodic table: 2

Isolation:

beryllium metal is available commercially and so would never normally be made in the laboratory. Its extraction from ores is complex. The mineral beryl, [Be3Al2(SiO3)6] is the most important source of beryllium. It is roasted with sodimu hexafluorosilicate, Na2SiF6, at 700°C to form beryllium fluoride. This is water soluble and the beryllium may be precipitated as the hydroxide Be(OH)2 by adjustment of the pH to 12.

Pure beryllium may be obtained by electrolysis of molten BeCl2 containing some NaCl.

The salt is added since the molten BeCl2 conducts very poorly.

Another method involves the reduction of beryllium fluoride with magnesium at 1300°C.

Physics properties: Boiling point; melting point; density; molar volume; thermal conductivity; and electrical resistivity; bulk modulus; critical temperature; superconductivity temperature; hardness (mineralogical, Brinell, and Vickers); linear expansion coefficient; Poisson's ratio; reflectivity; refractive index; rigidity modulus; Young's modulus; velocity of sound

Beryllium is a silvery white metal.

The surface of beryllium metal is covered with a thin layer of oxide that helps protect the metal from attack by air.

It does not oxidize in air even at 600°C. However, powdered beryllium metal does burn in air to give a mixture of white beryllium oxide, BeO, and beryllium nitride, Be3N2. Beryllium oxide is more normally made by heating beryllium carbonate.

2Be(s) + O2(g) → 2BeO(s)

3Be(s) + N2(g) → Be3N2(s)

Beryllium metal does not react with water or steam, even if the metal is heated to red heat.

Reaction of beryllium with the halogens

Beryllium metal reacts chlorine, Cl2, or bromine, Br2, to form the beryllium dihalides beryllium (II) chloride, BeCl2, and beryllium (II) bromide, BeBr2, respectively.

Be(s) + Cl2(g) → BeCl2(s)
Be(s) + Br2(g) → BeBr2(s)

Reaction of beryllium with acids

The surface of beryllium metal is covered with a thin layer of oxide that helps protect the metal from attack by acids, but powdered beryllium metal dissolves readily in dilute acids such as sulphuric acid, H2SO4, hydrochloric acid, HCl, or nitric acid, HNO3, to form solutions containing the aquated Be(II) ion together with hydrogen gas, H2.

Reaction of beryllium with bases

Beryllium metal dissolves readily in dilute aquesous base solutions such as sodium hydroxide, NaOH, to form Be(II) complexes together with hydrogen gas, H2. Magnesium (immediately below beryllium in the periodic table) does not do this.

Here is some information about the crystal structure of beryllium.

Space group:

P63/mmc (Space group number: 194)

Structure: hcp (hexagonal close-packed)
Cell parameters:
a: 228.58 pm

b: 228.58 pm

c: 358.43 pm

α: 90.000°

β: 90.000°
γ: 120.000°

Emeralds and beryl were both known to early Egyptians but it was not realised until the end of the 18th century that they are the same mineral, now called beryllium aluminium silicate: [Be3Al2(SiO3)6]. The element was recognised by M.-L. Vauquelin in 1798 in beryl and emeralds. The metal was isolated much later on in 1828 by Friederich Wöhler (and independently by A.-A.B. Bussy) by the action of potassium on BeCl2 in a platinum crucible.

Beryllium was discovered by Nicholas Louis Vauquelin (1763-1829) at 1797 in France.

Origin of name:

from the Greek word "beryllos" meaning "beryl"

Size of beryllium in several environments



One measure of size is the element-element distance within the element. The bond length in BeBe is: 222.6 pm.

It is not always easy to make sensible comparisons between the elements however as some bonds are quite short because of multiple bonding (for instance the O=O distance in O2 is short because of the the double bond connecting the two atoms.

There are several other ways ways to define radius for atoms and ions. Follow the appropriate hyperlinks for literature references and definitions of each type of radius.

All values of radii are given in picometres (pm). Conversion factors are:

1 pm = 1 x 10-12 metre (meter)

100 pm = 1 Ångstrom

1000 pm = 1 nanometre (nm, nanometer)
Neutral radii

The size of neutral atoms depends upon the way in which the measurement is made and the environment. Follow the appropriate hyperlinks for definitions of each radius type.

The problem is its meaning, which is clearly very different in different sources and books. Two values are given here, one is based upon calculations and the other upon observation - follow the appropriate link for further details.

Ionic radii

This table gives some ionic radii. In this table, geometry refers to the arrangment of the ion's nearest neighbours. Size does depend upon geometry and environment. For electronic configurations, where it matters, the values given for octahedral species are low spin unless stated to be high spin. The terms low spin and high spin refer to the electronic configurations of particular geomtries of certain d-block metal ions. Further information is available in inorganic chemistry textbooks, usually at Level 1 or First Year University level. For definitions of ionic radius and further information, follow the hypertext link.

Ion Coordination type Radius / pm
Be(II) 4-coordinate, tetrahedral 41
Be(II) 6-coordinate, octahedral 59
Pauling ionic radii

This table shows Pauling radii for beryllium
Ion Pauling radius / pm
Be(I) 44
Be(II) 31

This section lists some binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and some other compounds of beryllium.

For each compound, a formal oxidation number for beryllium is given, but the usefulness of this number is limited for p-block elements in particular.

Based upon that oxidation number, an electronic configuration is also given but note that for more exotic compounds you should view this as a guide only.

The term hydride is used in a generic sense to indicate compounds of the type MxHy and not necessarily to indicate that any compounds listed behave chemically as hydrides. In compounds of beryllium (where known), the most common oxidation numbers of beryllium are: 2.

Hydrides

The term hydride is used to indicate compounds of the type MxHy and not necessarily to indicate that any compounds listed behave as hydrides chemically.

Beryllium dihydride: BeH2

Fluorides

Beryllium difluoride: BeF2
Chlorides

Beryllium dichloride: BeCl2

Bromides

Beryllium dibromide: BeBr2

Iodides

Beryllium diiodide: BeI2

Oxides

Beryllia: BeO

Sulfides

Beryllium sulphide: BeS

Beryllium selenide: BeSe

The standard reduction potentials given here for aqueous solutions are adapted from the IUPAC publication reference 1 with additional data and an occasional correction incorporated from many other sources, in particular, references 2-7.

A.J. Bard, R. Parsons, and J. Jordan, Standard Potentials in Aqueous Solutions, IUPAC (Marcel Dekker), New York, USA, 1985.

N.N. Greenwood and A. Earnshaw, Chemistry of the Elements, 2nd edition, Butterworth-Heinemann, Oxford, UK, 1997.

F.A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry, 5th edition, John Wiley & Sons, New York, USA, 1988.

B. Douglas, D.H. McDaniel, and J.J. Alexander, Concepts and models of Inorganic Chemistry, 2nd edition, John Wiley & Sons, New York, USA, 1983.

D.F. Shriver, P.W. Atkins, and C.H. Langford, Inorganic Chemstry, 3rd edition, Oxford University Press, Oxford, UK, 1999.

J.E. Huheey, E.A. Keiter, and R.L. Keiter in Inorganic Chemistry : Principles of Structure and Reactivity, 4th edition, HarperCollins, New York, USA, 1993.

Beryllium: enthalpies and thermodynamic properties

Enthalpies

Enthalpy of fusion: 7.95 kJ mol-1

Enthalpy of vaporisation: 297 kJ mol-1

Thermodynamic data

State ΔfH° ΔfG° S° CpH H°298.15-H°0

Units kJ mol-1 kJ mol-1 J K-1 mol-1 J K-1 mol-1 kJ mol-1

Solid *0 0 *9.50 ± 0.08 16.4 *1.950 ±

Gas *324 ± 5 287 *136.275 ± 0.003 20.79 *6.197 ± 0.001

Notes

This tables gives a few thermodynamic data. Most values are those given in the NBS technical notes (reference 1) after conversion from the units used within those notes. Values labelled with an asterisk (*) are Committee on Data for Science and Technology (CODATA) agreed values for the thermodynamic properties of key chemical substances (reference 2). These values are published in a number of places including the WWW (reference 3).