Lead (Pb)

Metallic gray

Lead is a dense, soft metal that built the Roman Empire's aqueducts and poisoned its emperors, and with [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p², the inert pair effect makes Pb²⁺ more stable than Pb⁴⁺. Lead's toxicity stems from mimicking calcium, crossing the blood-brain barrier and accumulating in bones.

Key metrics

Density11.34g/cm³

Melting point601K

Boiling point2,022K

Electronegativity2.33Pauling

Discovery

-7000discovered

Discovered by: Ancient civilizations
Reactivity profile: Corrosion resistant
Reactivity: Low
Bonding: Metallic

Electron configuration

\textcolor{#6b7280}{[Xe]}\; \textcolor{#a855f7}{4_{f}^{14}}\; \textcolor{#22c55e}{5_{d}^{10}}\; \textcolor{#ef4444}{6_{s}^{2}}\; \textcolor{#3b82f6}{6_{p}^{2}}

[Xe] 4f14 5d10 6s2 6p2

Wave function

\Psi_{\text{Pb}} \approx \frac{1}{\sqrt{82!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{82}(\mathbf{r}_{82}) \right|

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

Crystal structure

Face-Centered Cubic

Lattice constantsa = 1.00

Cell anglesα = β = γ = 90°

Coordination number12

Atoms per cell4

Atomic packing factor0.74

Physical properties

Atomic radius: 154 pm
Ionization energy: 716 kJ/mol
Electron affinity: 35 kJ/mol
Crystal structure: Face-centered cubic (fcc)

Oxidation states

+2+4

Acid/base

Basic

Strongly acidicStrongly basic

State at 25 °CSolid

601 K2022 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

357.3nmPb I (UV)UV40%

368.3nmPb I (UV)UV60%

405.8nmPb I (violet)Violet100%

Dominant line 405.8 nmRange 357–406 nmTransitions 3