- a steel-gray, bivalent, hard, light, metallic element, the salts of which are sweet: used chiefly in copper alloys for better fatigue endurance, in springs, and in electrical contacts. Symbol: Be; atomic weight: 9.0122; atomic number: 4; specific gravity: 1.8 at 20° C.
- a corrosion-resistant toxic silvery-white metallic element that occurs chiefly in beryl and is used mainly in X-ray windows and in the manufacture of alloys. Symbol: Be; atomic no: 4; atomic wt: 9.012; valency: 2; relative density: 1.848; melting pt: 1289°C; boiling pt: 2472°C
