Silicon 1.2

Name, symbol, number
silicon, Si, 14
Element category
metalloids
Group, period, block
14, 3, p
Appearance
crystalline, reflective
bluish-tinged faces
Standard atomic weight
28.0855(3) g·mol−1
Electron configuration
[Ne] 3s2 3p2
Electrons per shell
2, 8, 4
Physical properties
Phase
solid
Density (near r.t.)
2.3290 g·cm−3
Liquid density at m.p.
2.57 g·cm−3
Melting point
1687 K(1414 °C, 2577 °F)
Boiling point
3538 K(3265 °C, 5909 °F)
Heat of fusion
50.21 kJ·mol−1
Heat of vaporization
359 kJ·mol−1
Specific heat capacity
(25 °C) 19.789 J·mol−1·K−1
Vapor pressure
P/Pa
1
10
100
1 k
10 k
100 k
at T/K
1908
2102
2339
2636
3021
3537
Atomic properties
Crystal structure
Diamond cubic
Oxidation states
Electronegativity
1.90 (Pauling scale)
Ionization energies(more)
1st: 786.5 kJ·mol−1
2nd: 1577.1 kJ·mol−1
3rd: 3231.6 kJ·mol−1
Atomic radius
117.6 pm
Atomic radius (calc.)
111 pm
Covalent radius
111 pm
Van der Waals radius
210 pm
Magnetic ordering
nonmagnetic
Thermal conductivity
(300 K) 149 W·m−1·K−1
Thermal expansion
(25 °C) 2.6 µm·m−1·K−1
Speed of sound (thin rod)
(20 °C) 8433 m/s
Young's modulus
150 GPa
Bulk modulus
100 GPa
Mohs hardness
7
CAS registry number
7440-21-3
Band gap energy at 300 K
1.12 eV