CHROMIUM
Element Name: Chromium
Atomic Number: 24
Element Symbol: Cr
Atomic weight: 59.9961
Did you know that ..
a toaster is a commonly used chromium element?
Chromium’s Physical properties
Description of the Element
Physical Properties:
State of matter at room temperature – Solid
Melting point temperature - 2180 K (1907 °C, 3465 °F)
Boiling point temperature – 2944 K (2671 °C, 4840 °F)
Color – Silver
Density – 7.19 g·cm−3
Hardness - 8.5
Texture - Solid
Malleability – It is malleable
Ductility Conductivity - 94 W/mK
Phase
Solid
Density (near r.t.)
7.19 g·cm−3
Liquid density at
m.p.
6.3 g·cm−3
Melting point
2180 K
(1907 °C, 3465 °F)
Boiling point
2944 K
(2671 °C, 4840 °F)
Heat of fusion
21.0 kJ·mol−1
Heat of vaporization 339.5 kJ·mol−1
Heat capacity
(25 °C) 23.35
J·mol−1·K−1
Chemical Properties:
Flammability Photosensitivity Combustibility Toxicity – Compounds can be very toxic if they are inhaled
Discovery of the Element
Who discovered the element? Johann Gottlob Lehmanns
Where was it discovered? Ural Mountains
What are the uses of the element? Chromium was primarily used as a component of paints and in
tanning salts but, now metal alloys account for 85% of the use of chromium.
When was it discovered? July 26, 1761
What are a few of the common uses or the historical uses of this element?
• Paints
• Tanning Salts
• Metal alloys
• Chemical Industry
• Refractory and Foundry Industries
List the way(s) in which the element appears naturally. How is it mined or extracted from the ground?
Chromium is mined as chromite ore. About two-fifths of the chromite ores and concentrates in the
world are produced in South Africa.
What are the main compounds formed by this element and the industrial uses of these compounds?
H2CrO4
What are the main environmental concerns about this element? Are its compounds causing pollution?
These compounds are often found in soil and groundwater at abandoned industrial sites, and
cause much need of enviromental cleanups.
Chromium salts color glass an emerald green.
It is used to make a brilliant yellow for painting.
Chromium salts are used in the tanning of leather.
Chromium is what makes a ruby red, and is used in producing synthetic rubies
Deanna Garber and April Murphy
Period 2