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Chromium

Cr

INTRODUCTION

Chromium is a common element,with about 21st in natural abundance among the elements in crustal rocks.Many precious stones owe their colour to the presence of chromium compounds.

It can replace part of the aluminum or iron in many minerals,imparting to them their unique colors and it can take on a high polish.Its name is derive fromthe Greek word Chroma (colour) due to the various colour of its compounds.

BASIC INFORMATIONS

  • Atomic Number
  • 24
  • Atomic Mass
  • 51.9961
  • Atomic radius
  • 0.117
  • Ionization energy
  • 652
  • Electronic config
  • 2,8,13,1
  • Principal Valency
  • +3 and +6
  • Density g/cm³
  • 7.14
  • Melting point °C
  • 1907
  • Boiling point °C
  • 2671
  • Type of Element
  • Metal
  • Electronegativity
  • 1.6
  • Element Category
  • Chromium Group
  • Appearance
  • Gray solid
  • Block
  • d-block
  • Period
  • 4
  • Group
  • 6
  • No of Isotopes
  • 26
  • Occurrence
  • Combine form
  • Abundance in ppm
  • 122
  • Year of Discovery
  • 1797

EXTRACTION

It is obtain by reducing it's oxide

OXIDATION STATES

+6,+5,+4,+3,+2,-1,-2 (Strongly acidic)

MAJOR SOURCE

Chromite

EXAMPLES OF COMPOUND PRESENT

Chromic oxide, Potassium dichromate, lead chromate

ECONOMIC IMPORTANCE

* Chromium makes up 10 percent or more of the final composition of the stainless steels.

* Due to its hardness,an alloy of chromium,cobalt and tungsten is used for high-speed metal-cutting tools.

* It is used extensively as a refractory due to its high melting point,its moderate thermal expansion and the stability of its crystalline structure.

* It serve as an important ingredient in several catalysts.

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