Cadmium has been used in nickel-cadmium batteries, protective coatings, and colored pigments. It also absorbs neutrons, giving it a specialized role in nuclear-reactor control. Commercial cadmium is largely obtained during zinc refining, linking this toxic metal to the processing of another element's ores.
FROM ELEMENT TO APPLICATION
AN ELEMENT IN CONTEXT
What supplies energy when a nickel–cadmium cell powers a circuit?
Cadmium-containing nickel–cadmium cell
FOLLOW THIS RELATIONSHIP
Combine complementary electrode materials
A nickel–cadmium cell contains cadmium-based and nickel-based electrodes within an electrochemical arrangement. Neither electrode alone describes the complete working battery system.
Explore the model (optional)
CdFORM → INTERACTION → CONSEQUENCE
Follow the explanation in either direction. These are authored steps, not a physical clock.
Optional: check your understanding
USE THE EXPLANATION
Which account correctly explains the energy source during discharge?
Atomic identity, reference properties and structure models
INTERACTIVE 3D48 visible sites
An electron censusDrag to rotate · scroll or pinch to zoom
[Kr] 4d10 5s2. Grouping electrons by principal shell connects the neutral-atom configuration to periodic-table patterns.
What this representation means
A three-dimensional counting diagram. Dots are count markers, not measured electron positions; spherical placement and spacing are arbitrary. There are no electron trajectories here. Orbitals describe quantum states.
Friedrich Stromeyer identified cadmium in 1817 while investigating unexpectedly colored zinc preparations. Other researchers, including Karl Meissner and Karl Karsten, also encountered the new substance during related investigations. Reports followed in 1818. The important lesson is that an impurity can be evidence: an unexpected result may reveal another element rather than merely indicating that an otherwise familiar preparation was performed badly.
1817
Unexpected zinc preparation investigated
Stromeyer identified cadmium through zinc-compound chemistry.
1818
Further reports appeared
Related investigations added evidence for the new element.
Cadmium occurs in the greenockite as cadmium , but practical recovery is closely tied to zinc processing. Cadmium can accompany zinc in such as sphalerite. Its supply therefore illustrates a byproduct relationship: separating one desired metal can also concentrate another element that was initially dispersed.
Cadmium is a soft metal whose compounds and have specialized uses. Its toxicity makes chemical form and exposure relevant when interpreting those uses. An industrial function is not evidence that a material is suitable for ordinary handling. Battery chemistry and also concern different physical processes.
Each section links its supporting references. Descriptions and diagrams were authored for this atlas. Source checks completed. Source checks dated 2026-09-06.
CITE THIS PAGE
Family labels and the group-3 layout are teaching conventions. A table position does not establish an unknown bulk property. Electronic configurations refer to neutral atoms; ions and material environments require their own account.
Read each reference property together with its units, conditions and the reference information below.
Not yet recorded: electron affinity, second ionization energy, ground-state term symbol, van der waals radius, thermal conductivity, specific heat capacity, electrical resistivity, crystal structure, lattice parameter a, space group, abundance in seawater, abundance in the universe, annual production, supply-risk listing, hazard classification, biological role, cas registry number, pubchem cid, wikidata item. These families are declared and awaiting an ingestion run against the source each names; they are listed here rather than shown as empty rows.
Physical
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Phase at 20 °C
solid
293.15 K, 101.325 kPa
Melting point in K
594.22 K
at standard pressure unless noted
Boiling point in K
1040 K
101.325 kPa
Density in g/cm³
8.65 g/cm³
solids and liquids at 293 K; gases at 273 K and 101.325 kPa
Atomic and electronic
Intended reference: Pauling electronegativity scale · Widely tabulated; original in The Nature of the Chemical Bond
Electronegativity in Pauling
1.69 Pauling
Pauling scale
First ionization energy in kJ/mol
867.8 kJ/mol
gas-phase neutral atom, ground state
Covalent radius in pm
144 pm
single-bond covalent radius
Common oxidation states
+2
states met in ordinary compounds; not exhaustive
Occurrence and identity
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Abundance in the crust in mg/kg
0.15 mg/kg
upper continental crust, mass fraction
Has stable isotopes
Yesderived
Discovery year in CE
1817 CEderived
WHERE IT SITS AMONG ITS NEIGHBORS
Electronegativity across period 5
Cd 1.69 Pauling · Cadmium
Electronegativity across period 5. Exact values.
Rb
0.82
Sr
0.95
Y
1.22
Zr
1.33
Nb
1.6
Mo
2.16
Tc
1.9
Ru
2.2
Rh
2.28
Pd
2.2
Ag
1.93
Cd
1.69
In
1.78
Sn
1.96
Sb
2.05
Te
2.1
I
2.66
Xe
2.6
Electronegativity down group 12
Cd 1.69 Pauling · Cadmium
Electronegativity down group 12. Exact values.
Zn
1.65
Cd
1.69
Hg
2
The trend uses the same reference-property values as the periodic table. Elements with no recorded value are left out of the line rather than drawn at zero.
