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5B10.810
Boron
MetalloidBoron is a metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in both the Solar system and the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals.
Phase: SolidAppearance: black-brown
2, 3
Physical Properties
Atomic Mass10.81 u
Density2.08 g/cm³
Melting Point2349 K
Boiling Point4200 K
Molar Heat11.087 J/(mol·K)
Period2
PhaseSolid
Chemical Properties
Electron Configuration1s2 2s2 2p1
Semantic Config[He] 2s2 2p1
Shells2, 3
Electron Affinity26.989 kJ/mol
Electronegativity2.04
Ionization Energies
IE1: 800.6 kJ/molIE2: 2427.1 kJ/molIE3: 3659.7 kJ/molIE4: 25025.8 kJ/molIE5: 32826.7 kJ/mol
Discovery
Discovered byJoseph Louis Gay-Lussac