Silicon

Si

Description

Silicon (Si)

Overview

Silicon is a brittle, blue-gray crystalline metalloid. It is a Group 14 element and serves as the primary semiconductor material for the modern electronics industry. It is the second most abundant element in the Earth's crust by mass ($28\%$).

Crystallographic Structure

Silicon utilizes the Diamond Cubic lattice system. This structure consists of two interpenetrating Face-Centered Cubic (FCC) sub-lattices displaced by a vector of $(1/4, 1/4, 1/4)$ along the body diagonal.

  • Lattice Parameter: $a = 5.4307$ Å
  • Atomic Packing Factor (APF): 0.34
  • Coordination Number: 4
  • Bonding: Strong covalent bonding in a tetrahedral geometry.

Properties

  • Atomic Number: 14
  • Atomic Mass: 28.085 u
  • Melting Point: 1,414°C
  • Boiling Point: 3,265°C
  • Density: 2.329 g/cm³
  • Band Gap: $1.12$ eV (Indirect)
  • Resistivity: Decreases as temperature increases (characteristic of semiconductors).

Applications

  • Semiconductors: High-purity silicon (Electronic Grade) is used for microchips, transistors, and integrated circuits.
  • Solar Energy: The active component in photovoltaic cells for converting sunlight into electricity.
  • Alloying: Used as an additive in aluminum and steel to improve castability and strength.
  • Silicones: Synthetic polymers (silicon-oxygen backbones) used in sealants, adhesives, lubricants, and medical applications.
  • Silica/Silicates: Used in the production of glass, ceramics, and cement.

Unit Cell Axes

a=5.43 b=5.43 c=5.43

Unit Cell Angles

α=90° β=90° γ=90°

Lattice Type

fcc

Grid Expansion

Appearance

Si Color
#7e838c
Bond Color
#94a3b8

Coordination

Atoms: 18Bonds: 28

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