Fluorine (F)

Pale yellow gas

Fluorine is the most reactive and electronegative element, found in toothpaste and non-stick pans, and as the most electronegative element (3.98 Pauling scale), fluorine forms the strongest single bonds with carbon. Its small atomic radius and high electron affinity drive its extreme reactivity.

Key metrics

Density0.001696g/cm³

Melting point53.48K

Boiling point85.03K

Electronegativity3.98Pauling

Discovery

1886discovered

Discovered by: Henri Moissan
Reactivity profile: Extremely Reactive
Reactivity: High
Bonding: Covalent

Electron configuration

\textcolor{#6b7280}{[He]}\; \textcolor{#ef4444}{2_{s}^{2}}\; \textcolor{#3b82f6}{2_{p}^{5}}

[He] 2s2 2p5

Wave function

\Psi_{\text{F}} \approx \frac{1}{\sqrt{9!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_9(\mathbf{r}_9) \right|

Probability density $|\Psi|^2$ across the F 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: 42 pm
Ionization energy: 1681 kJ/mol
Electron affinity: 328 kJ/mol
Crystal structure: Orthorhombic

Oxidation states

-1

Acid/base

Acidic

Strongly acidicStrongly basic

State at 25 °CGas

53.48 K85.03 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

527.0nmF I (green)Green40%

685.6nmF I (red)Red100%

703.7nmF IIR70%

Dominant line 685.6 nmRange 527–704 nmTransitions 3