Atomic Number: 4

Atomic Weight: 9.012182

A divalent element, beryllium is found naturally only combined with other elements in minerals.

Notable gemstones which contain beryllium include beryl (aquamarine, emerald) and chrysoberyl.

The free element is a steel-gray, strong, lightweight brittle alkaline earth metal.

It is primarily used as a hardening agent in alloys, notably beryllium copper.

Structurally, beryllium's very low density (1.85 times that of water), high melting point (1287 °C), high temperature stability and low coefficient of thermal expansion, make it in many ways an ideal aerospace material, and it has been used in rocket nozzles and is a significant component of planned space telescopes.

Because of its relatively high transparency to X-rays and other forms of ionizing radiation, beryllium also has a number of uses as filters and windows for radiation and particle physics experiments.

Commercial use of beryllium metal presents technical challenges due to the toxicity (especially by inhalation) of beryllium-containing dusts.

Beryllium produces a direct corrosive effect to tissue, and can cause a chronic life-threatening allergic disease called berylliosis in susceptible persons.

Because it is not synthesized in stars, beryllium is a relatively rare element in both the Earth and the universe.

The element is not known to be necessary or useful for either plant or animal life.

Contents

1 Characteristics

1.1 Physical properties