Cadmium (Cd)

Soft, bluish-white metal

Cadmium is a soft, toxic metal found in rechargeable batteries and the bright yellow of sunset, and with a filled 4d¹⁰ shell, cadmium is highly toxic as it mimics zinc in biological systems, disrupting enzyme function. CdS pigment gives a brilliant yellow color and cadmium telluride is used in thin-film solar cells.

Key metrics

Density8.65g/cm³

Melting point594K

Boiling point1,040K

Electronegativity1.69Pauling

Discovery

1817discovered

Discovered by: Friedrich Stromeyer
Reactivity profile: Toxic metal
Reactivity: Medium
Bonding: Metallic

Electron configuration

\textcolor{#6b7280}{[Kr]}\; \textcolor{#22c55e}{4_{d}^{10}}\; \textcolor{#ef4444}{5_{s}^{2}}

[Kr] 4d10 5s2

Wave function

\Psi_{\text{Cd}} \approx \frac{1}{\sqrt{48!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{48}(\mathbf{r}_{48}) \right|

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

Crystal structure

Hexagonal Close-Packed

Lattice constantsa 1.00 · b 1.00 · c 1.63

Cell anglesα 90° · β 90° · γ 120°

Coordination number12

Atoms per cell2

Atomic packing factor0.74

Physical properties

Atomic radius: 151 pm
Ionization energy: 868 kJ/mol
Electron affinity: 0 kJ/mol
Crystal structure: Hexagonal close-packed (hcp)

Oxidation states

Acid/base

Basic

Strongly acidicStrongly basic

State at 25 °CSolid

594 K1040 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

479.9nmCd I (blue)Blue70%

508.6nmCd I (blue-green)Cyan100%

533.8nmCd I (green)Green50%

Dominant line 508.6 nmRange 480–534 nmTransitions 3