Phosphorus (P)

White, red, or black solid

Phosphorus glows in the dark and is essential for DNA, bones, and energy transfer in cells, and with three unpaired 3p electrons, phosphorus exists in multiple allotropes—white (toxic, pyrophoric), red (stable), and black (semiconductor). It forms the phosphate backbone of all nucleic acids.

Key metrics

Density1.82g/cm³

Melting point317.3K

Boiling point553K

Electronegativity2.19Pauling

Discovery

1669discovered

Discovered by: Hennig Brand
Reactivity profile: Highly Reactive Reactive Nonmetal
Reactivity: High
Bonding: Covalent

Electron configuration

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

[Ne] 3s2 3p3

Wave function

\Psi_{\text{P}} \approx \frac{1}{\sqrt{15!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{15}(\mathbf{r}_{15}) \right|

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

Crystal structure

Orthorhombic

Lattice constantsa 1.00 · b 1.30 · c 0.90

Cell anglesα = β = γ = 90°

Coordination number—

Atoms per cell—

Atomic packing factor0.60

Physical properties

Atomic radius: 110 pm
Ionization energy: 1012 kJ/mol
Electron affinity: 72 kJ/mol
Crystal structure: Orthorhombic

Oxidation states

-3+3+5

Acid/base

Acidic

Strongly acidicStrongly basic

State at 25 °CSolid

317.3 K553 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

476.6nmP I (blue)Blue50%

526.1nmP IGreen60%

539.1nmP I (green)Green100%

Dominant line 539.1 nmRange 477–539 nmTransitions 3