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Discovered in 1797 by Louis Nicolas Vauquelin.
 Common name: Chrome
 Origin of name: From the Greek word Chroma
(means color).
Early 1900s– Cr became an important ingredient in corrosionresistant metals
1959 - Schwartz & Mertz identify Cr as active “Glucose
Tolerance Factor” (GTF)
Later: chromium was thought of as a cofactor with insulin,
necessary for normal glucose utilization
Inorganic salt of chromium were utilized poorly compared to
an organically bound form of chromium present in brewer's
yeast Short Historical perspective
1974 - Polansky shows that the active principle of GTF is a Crniacin complex
1975 - Jeejeebhoy makes first report of human Cr deficiency
Total parenteral nutrition (TPN) deficient in Cr
Symbol Cr and atomic number
 Atomic weight: 51.9961 g/mol
 Transition metal
 25th most abundant
 Steel-gray
 Mostly known as the “chrome”
plating on cars, or the shiny
metal in the bathroom
24 Protons, 24 Electrons,
28 Neutrons
Atomic Number: 24
Atomic Mass: 52 AMU
Steel-Gray, Lustrous,
Hard Metal with a high
High Melting Point, Solid
Good conductor of
Thermal and Electrical
Compounds are toxic
Chromium’s Crystalline Structure
Chromium is
in Period #4
Chromium is
Group #6
Chromium is
Block d
Chromium is used to
harden steel,
manufacture stainless
steel, and form many
useful alloys.
is also used
to give
glass its
Green color.
Chromium is found naturally in
rocks, soil, plants, animals, and
even humans.
 Chromium can be found the
following common food sources:
beef, brewer’s yeast, brown rice,
cheese, turkey, fish and whole
grains. It is found in other foods
including: Chicken, corn,
potatoes, eggs, and green beans.
 It can also be found in the
following plants and herbs: catnip,
horsetail, oat straw, red clover,
and sarsaparilla.
Oxidation States and Reactivity
Chromium does not react with oxygen or water at
room temperature.
Chromium react directly with Fluorine.
The most common Oxidation States of
Chromium are +2, +3, and +6, with +3 being
the most stable.