Beryllium

Beryllium,  ₄Be

General properties
Name, symbol	Beryllium, Be
Appearance	Silvery-white
Beryllium in the periodic table
- ↑ Be ↓ Mg Lithium ← Beryllium → Boron
Atomic number	4
Standard atomic weight (Ar)	9.0121831(5)
Group, block	(alkaline earth metals); s-block
Period	period 2
Electron configuration	[He] 2s2
per shell	2, 2
Physical properties
Silvery-white
Phase	Solid
Melting point	1560 K ​(1287 °C, ​​2349 °F)
Boiling point	2742 K ​(2469 °C, ​​4476 °F)
Density near r.t.	1.85 g/cm3
when liquid, at	1.69 g/cm3
Critical point	5205 K,  MPa
Heat of fusion	12.2 kJ/mol
Heat of	292 kJ/mol
Molar heat capacity	16.443 J/(mol·K)
pressure
Atomic properties
Oxidation states	+2, +1 ​(an amphoteric oxide)
Electronegativity	Pauling scale: 1.57
energies	1st: 899.5 kJ/mol 2nd: 1,757.1 kJ/mol 3rd: 14,848.7 kJ/mol
Atomic radius	empirical: 112 pm
Covalent radius	96±3 pm
Van der Waals radius	153 pm
Miscellanea
Crystal structure	​Hexagonal close-packed (hcp)
Speed of sound thin rod	12,890 m/s (at 20 °C)
Thermal expansion	11.3 µm/(m·K) (at 25 °C)
Thermal conductivity	200 W/(m·K)
Electrical resistivity	36·10-9 Ω·m
Magnetic ordering	Diamagnetic
Young's modulus	287 GPa
Shear modulus	132 GPa
Bulk modulus	130 GPa
Poisson ratio	0.032
Mohs hardness	5.5
Vickers hardness	1670 MPa
Brinell hardness	590–1320 MPa
CAS Registry Number	7440-41-7
History
Discovery	Louis Nicolas Vauquelin (1798)
First isolation	Friedrich Wöhler & Antoine Bussy (1828)

Beryllium is the chemical element with the symbol Be and atomic number 4.

Properties

Chemical

Beryllium is more chemically similar to aluminium than its close neighbors in the periodic table, due to having a similar charge-to-radius ratio. A protective oxide layer forms around beryllium that prevents further reactions with air unless heated above 1000 °C. It will dissolve in alkali solutions and non-oxidizing acids, such as hydrochloric acid releasing hydrogen gas, but not in nitric acid, as it forms a protective oxide layer, similar to aluminium. It will also dissolve in alkali solutions.

Like aluminium halides, beryllium halides tend to be covalent due to the small atomic radius and high charge density.

Physical

Beryllium is a white-gray and hard metal, brittle at room temperature and has a close-packed hexagonal crystal structure. It has exceptional stiffness (Young's modulus 287 GPa) and a reasonably high melting point. Beryllium has high specific heat (1925 J·kg⁻¹·K⁻¹) and thermal conductivity (216 W·m⁻¹·K⁻¹), which make beryllium the metal with the best heat dissipation characteristics per unit weight. Beryllium has the fastest speed of sound in any known metal, with a value of 12.9 km/s at standard conditions.

Availability

Beryllium samples can be bought online from Metallium, in ampoules (recommended) or pellets and rods.

Beryllium can be found in beryllium copper/bronze tools, in concentrations between 0.5—3%. Extraction is a complex process and may not worth the effort, especially due to the low concentration of Be.

Cavity magnetrons used in microwave ovens have a beryllium oxide insulator at both ends, which is usually colored in pink or white, right above the brass mesh gasket and the other near the contacts. However, extracting the metal from the oxide is very dangerous, as beryllium compounds are more toxic than the metal, due to being soluble.

Preparation

Beryllium metal can be prepared by reducing beryllium chloride with potassium metal, in an inert atmosphere:

BeCl₂ + 2 K → 2 KCl + Be

It can also be prepared from the electrolysis of a mixture of molten beryllium fluoride and sodium fluoride.

Projects

• Synthetic gemstones
• X-ray window
• Element collecting

Handling

Safety

Although beryllium and beryllium compounds have interesting properties worth studying, both are extremely toxic, and inhaling their dust can result in a serious medical condition called "berylliosis". The International Agency for Research on Cancer (IARC) lists beryllium and beryllium compounds as Category 1 carcinogens.

Storage

Bulk beryllium metal should be kept away from strong acids or sharp objects. Powdered beryllium must be kept in closed containers, away from any draft.

Disposal

Best to try to recycle it.

References

Relevant Sciencemadness threads

• Extraction of beryllium from beryl