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Chroom

Chroom, in English chromium, is a chemical element with the symbol Cr and atomic number 24. It is a transition metal valued for its hardness, high melting point, and the stability of a protective oxide layer that forms in air.

Chromium is a silvery metal that readily forms chromium(III) oxide (Cr2O3), which adheres to the surface and

Occurrence and production: In nature, chromium is found primarily in chromite ore (iron chromium oxide, FeCr2O4).

History: The element was identified in 1797 by French chemist Louis Nicolas Vauquelin during analysis of crocoite.

Applications: The most important use is in stainless steel and other alloys to improve hardness and corrosion

Safety: Hexavalent chromium compounds are toxic and carcinogenic; exposure is regulated and protective measures are required.

provides
corrosion
resistance
in
stainless
steels.
It
has
a
melting
point
of
about
1,907°C
and
a
density
of
7.14
g/cm3;
its
compounds
exhibit
a
range
of
colors,
which
gave
chromium
its
name
from
the
Greek
word
chroma,
meaning
color.
Major
producers
include
South
Africa,
Kazakhstan,
India,
and
Turkey.
Commercial
chromium
is
produced
by
mining
chromite,
smelting
to
ferrochromium,
and
refining
to
metallic
chromium
or
its
compounds
for
use
in
pigments
and
catalysts.
The
name
chromium
derives
from
chroma,
color,
reflecting
the
colorful
compounds
chromium
forms.
resistance.
Chrome
plating
provides
a
hard,
glossy,
wear-resistant
finish.
Chromium(III)
oxide
is
used
as
a
green
pigment;
chromium(VI)
compounds
have
uses
in
pigments
and
tanning
but
are
hazardous.
Metallic
chromium
is
relatively
inert
but
processing
should
minimize
inhalation
or
ingestion
of
chromium
compounds.