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Periodic Table

beryllium

Atomic number: 4
Atomic weight: 9.012182
Symbol: Be
Group number: 2
Electronic configuration: [He].2s2

Description

Beryllium is a Group 2 (IIA) element. At ordinary temperatures beryllium resists oxidation in air. Its ability to scratch glass is probably due to the formation of a thin layer of the oxide. Aquamarine and beryl are precious forms of the oxide beryl.

General information

Discoveror: Nicholas Louis Vauquelin
Date discovered: 1797
Discovered at: France
Meaning of name: From the Greek word "beryllos" meaning "beryl"

Physical data

Standard state: solid at 298 K
Colour: lead grey
Density of solid at ambient temperature/kg m-3: 1848
Molar volume/cm3: 4.85

Radii /pm

Atomic: 112
Covalent (single bond):
Pauling radius for the ion [Be]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius108.5no datano datano data

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 1.57
Allred Rochow: 1.47

Crystal Structure

structure: hcp (hexagonal close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.

ball-and-stick.gif

Temperatures (/K)

melting point: 1560
boiling point: 2742

Enthalpies /kJ mol-1

fusion: 7.95
vaporization: 297

single bond enthalpies:
Be-F Be-Cl Be-Br Be-I Be-Be
632 461 372 289 59

Ionization enthalpies /kJ mol-1

Number Enthalpy
1st899.5
2nd1757.1
3rd14848
4th21006

Isotopes

This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
9Be9.0121822 (4)100

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/Be.html