What is the atomic number of Cadmium?

Cadmium has atomic number 48, meaning each atom contains 48 protons in its nucleus.

What is the electron configuration of Cadmium?

The full electron configuration of Cadmium is [Kr] 4d10 5s2. It has a completely filled d-subshell, which explains its stable +2 oxidation state.

Yes. Cadmium is highly toxic and classified as a human carcinogen (Group 1 by IARC). It accumulates in the kidneys and can cause itai-itai disease with chronic exposure. Proper protective equipment is required when handling cadmium and its compounds.

What is Cadmium mainly used for?

The largest uses are in nickel-cadmium (Ni-Cd) rechargeable batteries, cadmium electroplating for corrosion resistance, cadmium sulfide and cadmium selenide pigments (yellow, orange, red), and as neutron-absorbing control rods in nuclear reactors.

What is the melting point of Cadmium?

Cadmium melts at 321.07 °C (609.93 °F, 594.22 K), which is relatively low for a transition metal.

How many naturally occurring isotopes does cadmium have?

Cadmium has 8 naturally occurring isotopes. Six are stable; ¹¹³Cd and ¹¹⁶Cd are primordial radioisotopes with extremely long half-lives. The most abundant is ¹¹⁴Cd at about 28.73%.

Cadmium Element Properties

Explore all key physical and chemical properties of Cadmium (Cd), atomic number 48, with interactive tabs and a live unit converter.

48 Cd Cadmium 112.414 u

Atomic Number

Atomic Mass

112.414 u

Group

Period

Block

d-block

Classification

Transition Metal

Standard State

Solid (25 °C)

Color

Bluish-white

Symbol

Overview of Cadmium

Cadmium is a soft, silvery-white metal with a slight bluish tinge. It is a Group 12 transition metal discovered in 1817 by Friedrich Stromeyer in Germany, found as an impurity in zinc carbonate. The name comes from the Latin cadmia (calamine, a zinc ore). Cadmium occurs naturally paired with zinc, and most commercial cadmium is recovered as a byproduct of zinc smelting.

Property	Value
Latin Name	Cadmium
Discoverer	Friedrich Stromeyer
Discovery Year	1817
Natural Occurrence	Rare; byproduct of zinc smelting
Abundance (Earth crust)	0.15 ppm
Abundance (Universe)	2 × 10⁻⁷ %
CAS Number	7440-43-9
Naturally Occurring Isotopes	8 (6 stable; ¹¹³Cd and ¹¹⁶Cd are very long-lived)
Most Abundant Isotope	¹¹⁴Cd (28.73%)

Physical Properties

Temperature Converter

Value

From

→

Result

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Property	Value
Density (at 20 °C)	8.65 g/cm³
Melting Point	321.07 °C (609.93 °F, 594.22 K)
Boiling Point	767 °C (1413 °F, 1040 K)
Heat of Fusion	6.21 kJ/mol
Heat of Vaporization	99.87 kJ/mol
Specific Heat	0.232 J/(g·K)
Thermal Conductivity	96.6 W/(m·K)
Electrical Resistivity	72.7 nΩ·m (at 22 °C)
Hardness (Mohs)	2.0
Crystal Structure	Hexagonal close-packed (hcp)
Lattice Constant a	2.979 Å
Magnetic Ordering	Diamagnetic
Sound Speed	2310 m/s
Young's Modulus	50 GPa
Bulk Modulus	42 GPa

Electronic Properties

Electron Shell Configuration

K (n=1) 2

/ 2

L (n=2) 8

/ 8

M (n=3) 18

/ 18

N (n=4) 18

/ 32

O (n=5) 2

/ 50

Full configuration: [Kr] 4d¹⁰ 5s²

Property	Value
Electron Configuration	[Kr] 4d¹⁰ 5s²
Electrons per Shell	2, 8, 18, 18, 2
Oxidation States	+2 (most common), +1 (rare)
Electronegativity (Pauling)	1.69
Atomic Radius (calc.)	151 pm
Covalent Radius	144 pm
Van der Waals Radius	158 pm
Ionization Energy 1st	867.8 kJ/mol
Ionization Energy 2nd	1631.4 kJ/mol
Ionization Energy 3rd	3616 kJ/mol
Electron Affinity	-68 kJ/mol (no stable anion)
Valence Electrons	2
Conductivity Type	Metallic conductor
Work Function	4.08 eV

Uses and Safety

Ni-Cd Batteries

Cadmium is the negative electrode in nickel-cadmium rechargeable batteries, widely used in power tools, emergency lighting, and portable electronics.

Electroplating

Cadmium plating provides excellent corrosion resistance for aerospace fasteners and marine hardware, especially in saltwater environments.

Pigments

Cadmium sulfide (yellow), cadmium selenide (red), and mixed crystals produce vivid, heat-stable pigments used in plastics, ceramics, and glass.

Nuclear Reactors

Cadmium's high neutron-absorption cross-section makes it ideal for control rods and shielding in nuclear reactors.

Solar Cells

Cadmium telluride (CdTe) thin-film solar cells are a cost-effective alternative to silicon, with efficiencies exceeding 22% in lab conditions.

Alloys

Cadmium lowers the melting point of alloys and improves bearing properties. Wood's metal and Lipowitz's alloy both contain cadmium.

Safety Warning

Cadmium is classified as a Group 1 human carcinogen by IARC.
Chronic exposure causes kidney damage, osteoporosis (itai-itai disease), and lung cancer.
OSHA PEL: 5 µg/m³ (air, 8-hour TWA); NIOSH IDLH: 9 mg/m³.
Always use respiratory protection and ventilation when machining or soldering cadmium-containing alloys.
Cadmium use in jewelry and children's products is restricted under EU RoHS and REACH regulations.

Regulatory Limit	Value	Authority
Air (PEL)	5 µg/m³ TWA	OSHA
Air (TLV-TWA)	10 µg/m³	ACGIH
Drinking Water	0.005 mg/L	WHO / EPA
Soil (residential)	1.4 mg/kg	EPA RSL
RoHS restriction	0.01% by weight	EU RoHS 2

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Summary

Cadmium (Cd) is a soft, bluish-white transition metal with atomic number 48 and atomic mass 112.414 u. It belongs to Group 12 of the periodic table and is most commonly found in the +2 oxidation state. Cadmium is widely used in rechargeable nickel-cadmium batteries, electroplating, pigments, and as a neutron absorber in nuclear reactors.

How it works

Select a property tab (Overview, Physical, Electronic, or Uses & Safety) to view different property categories.
Use the temperature converter to switch melting and boiling points between Celsius, Fahrenheit, and Kelvin.
Click any property row to highlight it for easy reading.
The electron configuration diagram shows the orbital shell arrangement visually.
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Use cases

Quick reference for chemistry students studying transition metals or Group 12 elements.
Engineers specifying cadmium-plated hardware or Ni-Cd battery components.
Teachers preparing lessons on periodic table properties or heavy metals.
Researchers cross-checking physical constants for cadmium compounds.
Safety officers reviewing cadmium toxicity and handling guidelines.
Hobbyist chemists identifying cadmium pigments in historical materials.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu