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Magnesium chromite

Magnesium chromite is an inorganic compound, a salt of magnesium and chromic acid with the formula Mg (CrO 2 ) 2 , dark green crystals, dissolves in water.

Magnesium chromite
General
Systematic
name
Magnesium chromite
Traditional namesMagnesium oxochromate (III); magnesium dichrom tetraoxide; magnesium chromate
Chem. formulaMgCr 2 O 4
Rat formulaMg (CrO 2 ) 2
Physical properties
conditiondark green crystals
Molar mass192.30 g / mol
Density4.4 g / cm³
Thermal properties
T. melt.2390 ° C
Classification
Reg. CAS number12053-26-8
Reg. EINECS number235-001-7

Getting

  • Sintering of oxides of magnesium and chromium :
MgO+Cr2O3→620oCMgCr2Ofour{\ displaystyle {\ mathsf {MgO + Cr_ {2} O_ {3} \ {\ xrightarrow {620 ^ {o} C}} \ MgCr_ {2} O_ {4}}}}  
  • Decomposition of magnesium chromate upon heating:
fourMgCrOfour→525-645oC2MgCr2Ofour+2MgO+3O2{\ displaystyle {\ mathsf {4MgCrO_ {4} \ {\ xrightarrow {525-645 ^ {o} C}} \ 2MgCr_ {2} O_ {4} + 2MgO + 3O_ {2}}}}  

Physical Properties

Magnesium chromite forms dark green crystals of cubic syngony , space group F d3m , cell parameters a = 0.832768 nm, Z = 8.

At 10 K, the transition to the phase of tetragonal syngony occurs, the space group I 4 1 / amd , cell parameters a = 0.589199 nm, c = 0.831677 nm, Z = 4.

Literature

  • Chemistry Handbook / Editorial: Nikolsky B.P. et al. - 2nd ed., rev. - M.-L.: Chemistry, 1966. - T. 1. - 1072 p.
  • CRC Handbook of Chemistry and Physics . - 89th Edition. - Taylor and Francis Group, LLC, 2008-2009.


Source - https://ru.wikipedia.org/w/index.php?title= Magnesium Chromite&oldid = 80372876


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