- noun a metallic element. It is used in making various alloys.
- A hard and brittle gray-white metallic element whose atomic number is 4. It is highly resistant to oxidation at ordinary temperatures, has excellent thermal and electrical conductivities, has an extremely low density, is nonmagnetic, and is highly permeable to X-rays. There are about 10 known isotopes, of which one is stable. It has many applications, including its use as a moderator and reflector of neutrons in nuclear reactors, as a source of neutrons when bombarded with alpha particles, in aerospace and satellite outer structures, as a window material for X-ray tubes, and in precision electronic components and devices such as navigational instruments. Its chemical symbol is Be.
- chemical symbolBe