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Cadmium Facts

Chemical & Physical Properties of Cadmium

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Photograph of cadmium metal, with a penny to show scale.

Photograph of cadmium metal, with a penny to show scale.

U.S. Geological Survey This is the electron configuration of a cadmium atom.

This is the electron configuration of a cadmium atom.

This is cadmium on the periodic table.

This is cadmium on the periodic table.

Todd Helmenstine
Periodic Table of the Elements

Cadmium

Cadmium Atomic Number: 48

Cadmium Symbol: Cd

Cadmium Atomic Weight: 112.411

Cadmium Discovery: Fredrich Stromeyer 1817 (Germany)

Electron Configuration: [Kr] 4d10 5s2

Word Origin: Latin cadmia, Greek kadmeia - ancient name for calamine, zinc carbonate. Cadmium was first discovered by Stromeyer as an impurity in zinc carbonate.

Properties: Cadmium has a melting point of 320.9°C, boiling point of 765°C, spcific gravity of 8.65 (20°C), and a valence of 2. Cadmium is a blue-white metal soft enough to be easily cut with a knife.

Uses: Cadmium is used in alloys with low melting points. It is a component of bearing alloys to given them a low coefficient of friction and resistance to fatigue. Most cadium is used for electroplating. It is also used for many types of solder, for NiCd batteries, and to control atomic fission reactions. Cadmium compounds are used for black and white television phosphors and in the green and blue phosphors for color television tubes. Cadmium salts have wide application. Cadmium sulfide is used as a yellow pigment. Cadmium and its compounds are toxic.

Sources: Cadmium is most commonly found in small quantities associated with zinc ores (e.g., sphalerite ZnS). The mineral greenockite (CdS) is another source of cadmium. Cadmium is obtained as a by-product during treatment of zinc, lead, and copper ores.

Element Classification: Transition Metal

Density (g/cc): 8.65

Melting Point (K): 594.1

Boiling Point (K): 1038

Appearance: soft, malleable, blue-white metal

Atomic Radius (pm): 154

Atomic Volume (cc/mol): 13.1

Covalent Radius (pm): 148

Ionic Radius: 97 (+2e)

Specific Heat (@20°C J/g mol): 0.232

Fusion Heat (kJ/mol): 6.11

Evaporation Heat (kJ/mol): 59.1

Debye Temperature (K): 120.00

Pauling Negativity Number: 1.69

First Ionizing Energy (kJ/mol): 867.2

Oxidation States: 2

Lattice Structure: Hexagonal

Lattice Constant (Å): 2.980

Lattice C/A Ratio: 1.886

 

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)

 

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