Beryllium

Symbol: Be
Atomic Number: 4
Atomic Weight: 9.01218
Element Classification: Alkaline-earth Metal
Discovered By: Louis-Nicholas Vauquelin
Discovery Date: 1798 (France)
Name Origin: Greek: beryllos, 'beryl' (a mineral).

Density (g/cc): 1.848
Melting Point (K): 1551
Boiling Point (K): 3243
Appearance: Hard, brittle, steel-gray metal
Atomic Radius (pm): 112
Atomic Volume (cc/mol): 5.0
Covalent Radius (pm): 90
Ionic Radius: 35 (+2e)
Specific Heat (@20C J/g mol): 1.824
Fusion Heat (kJ/mol): 12.21
Evaporation Heat (kJ/mol): 309
Thermal Conductivity (@25C W/m K):
Debye Temperature (K): 1000.00
Pauling Negativity Number: 1.57
First Ionizing Energy (kJ/mol): 898.8
Oxidation States: 2
Electronic Configuration: [He] 2s2
Lattice Structure: Hexagonal (HEX)
Lattice Constant (): 2.290
Lattice C/A Ratio: 1.567

Mineral Hardness [no units]: 5.5
Brinell Hardness [/MN m-2]: 600
Vickers Hardness [/MN m-2]: 1670

Note: Beryllium is a difficult metal to prepare and presents a health risk to the metallographer. Only those familiar with the toxicology of Be, and are properly equipped to deal with these issues, should work with the metal. The grinding dust is extremely toxic. Wet cutting prevents air contamination but the grit must be disposed properly. As with Mg, Be is easily damaged in cutting and grinding forming mechanical twins. Light pressures are required. Although some authors claim that water cannot be used, even when grinding Be, others report no difficulties using water. Attack-polishing agents are frequently used when preparing Be and many are recommended.

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