Silicon (Si)

Dark gray metalloid

Silicon is the element that powers every computer chip and solar cell on the planet, and as a metalloid with [Ne] 3s² 3p² configuration, silicon's semiconductor properties arise from its four valence electrons forming a diamond cubic crystal lattice. It makes up 28% of Earth's crust by mass.

Key metrics

Density2.33g/cm³

Melting point1,687K

Boiling point3,538K

Electronegativity1.9Pauling

Discovery

1824discovered

Discovered by: Jöns Jakob Berzelius
Reactivity profile: Reactive at High Temperatures
Reactivity: Medium
Bonding: Covalent

Electron configuration

\textcolor{#6b7280}{[Ne]}\; \textcolor{#ef4444}{3_{s}^{2}}\; \textcolor{#3b82f6}{3_{p}^{2}}

[Ne] 3s2 3p2

Wave function

\Psi_{\text{Si}} \approx \frac{1}{\sqrt{14!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{14}(\mathbf{r}_{14}) \right|

Probability density $|\Psi|^2$ across the Si valence shell.

Crystal structure

Diamond Cubic

Lattice constantsa = 1.00

Cell anglesα = β = γ = 90°

Coordination number4

Atoms per cell8

Atomic packing factor0.34

Physical properties

Atomic radius: 118 pm
Ionization energy: 787 kJ/mol
Electron affinity: 134 kJ/mol
Crystal structure: Diamond cubic

Oxidation states

-4+4

Acid/base

Acidic

Strongly acidicStrongly basic

State at 25 °CSolid

1687 K3538 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

390.6nmSi I (violet)UV100%

410.3nmSi IViolet70%

570.1nmSi I (yellow)Yellow40%

Dominant line 390.6 nmRange 391–570 nmTransitions 3