• Class: Non-Metals
• Period: 3
• IUPAC group: 14
• Traditional: IVb

• Discovered in: 1824 by Berzelius
• Origin of name: Latin: silex or silicis, (flint)
• Historical or alternate name:

Sand, quartz, rock crystal, amethyst, agte, flint, jasper, opal, clay, mica

Black, amorphous to blue-grey, metallic crystals. Solid form unreactive with Oxygen, water and most acids. Dissolves in hot alkali.

• Atmosphere: ~0.0 ppm
• Primitive mantle: 233000.0 ppm
• Sea water: 3.0 ppm
• Metallic meteorite: 106700.0 ppm
• Continental crust: 267700.0 ppm
• Solar photosphere: 7.65 log of abundance
• Oceanic crust: 231000.0 ppm
• Solar system: 1.00E+6 relative to Si=1.0e6

   Hazards

Flammable. Silica dust is a moderately toxic acute irritant. Prolonged dust inhalation may lead to chronic pulmonary disease..

   Human daily limits

• Lower:1.0
• Upper:100.0

Silicon Physical Properties

 Transitional Data

• State: Solid
• Density: 2.33 g/cm3

 Molar enthalpy

• Atomization: 451.29 kJ mol-1
• Fusion: 39.6 kJ mol-1
• Vaporization: 383.3 kJ mol-1

 Transition points

• Melting point: 1683.0 K
• Boiling point: 2628.0 K
• Critical temperature: 5159.0 K

 Molar properties

• Atomic weight: 28.0855 g/mole
• Molar volume: 12.132 cm3 mol-1

 Crystal structure sequence

diamond-cubic

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 18.83
  • Heat Capacity 20.00

• State: gas
  • Enthalpy 455.6
  • Gibbs function 411.3
  • Entropy 167.97
  • Heat Capacity 22.251

 Miscellaneous physical

• Electrical resistivity: 10.0 µ-ohms/cm
• Debye temperature: 645.0 K
• Thermal conductivity: 148.0 W / m / K
• Coefficient of linear expansion: 2.6Coef. per K
• Mass magnetic susceptibility: -1.8e-9
• X-ray diffraction mass absorption coefficients:
• CuK: 60.6 (µ/p)/cm2 g-1
• MoK: 6.44 (µ/p)/cm2 g-1

Silicon Chemical Properties

 Chemical basics:

• Oxidation states: -4 +2 +4
• Molecular wt: 28.0855 g/mole

 Radii

• Covalent: 117 pm
• Atomic: 117.0 pm
• Van der Waals: 200 pm

 Ions:

• ion: +4 pm 40.0

 Covalent bonds

 Effective nuclear charge

• Slater: 4.15
• Clementi: 4.29
• Froese-Fischer: 4.48

 Electronegativity

• Pauling: 1.9
• Allred-Rochow: 1.74

 Standard reactions

Silicon Nuclear Properties

• Known 8
• Listed 4

• Known 25 - 31
• Listed 28 - 32

• % Occ.:Natural 92.23%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 4.67%
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 1/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 3.10%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 108.0 years
  • Decay mode: Beta-
  • Source: Cosmic irradiation.
• Notes date

• Isotope Cross-section 0.160±0.020 barns

• Absolute sensitivity: 3.69e-4 1H=1.0
• Relative sensitivity: 7.84e-3 1H=1.0
• Receptivity: 2.09 13C=1.0
• Magnetogyric ratio: -5.3146e7 rad / T / s
• Quadropole moment: m2
• Frequency: 19.865 MHz
• Reference: Si(CH3)4

Silicon Energy Properties

Electrons

• Ground state electron configuration: [Ne] 3s2 3p2
• Electron affinity: 133.6 kJ mol-1
• Filling orbitals:

Spectral lines

 Ionization energies

 Atomic energy levels