Sodium dichromate

Sodium dichromate
Names
IUPAC name
Sodium dichromate
Other names
Chromic acid disodium salt
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.031.070 Edit this at Wikidata
EC Number
  • 234-190-3
21597
RTECS number
  • HX7750000
    HX7750000 (dihydrate)
UNII
UN number 3288
  • InChI=1S/2Cr.2Na.7O/q;;2*+1;;;;;;2*-1 checkY
    Key: KIEOKOFEPABQKJ-UHFFFAOYSA-N checkY
  • InChI=1/2Cr.2Na.7O/q;;2*+1;;;;;;2*-1/rCr2O7.2Na/c3-1(4,5)9-2(6,7)8;;/q-2;2*+1
    Key: KIEOKOFEPABQKJ-RXLKZJBDAW
  • [Na+].[Na+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O
Properties
Na2Cr2O7
Molar mass 261.97 g/mol (anhydrous)
298.00 g/mol (dihydrate)
Appearance bright orange
Odor odorless
Density 2.52 g/cm3
Melting point 356.7 °C (674.1 °F; 629.8 K)
Boiling point 400 °C (752 °F; 673 K) decomposes
73 g/100 mL at 25 °C
Solubility in other solvents soluble in methanol, ethanol
1.661 (dihydrate)
Hazards
GHS labelling:
GHS03: OxidizingGHS05: CorrosiveGHS06: ToxicGHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Warning
H272, H301, H312, H314, H317, H330, H334, H340, H350, H360, H372, H410
P201, P202, P210, P220, P221, P260, P261, P264, P270, P271, P272, P273, P280, P281, P284, P285, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P304+P341, P305+P351+P338, P308+P313, P310, P312, P314, P320, P321, P322, P330, P333+P313, P342+P311, P363, P370+P378, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
4
0
1
OX
Lethal dose or concentration (LD, LC):
50 mg/kg
Safety data sheet (SDS) ICSC 1369
Related compounds
Other anions
 Sodium chromate
Sodium molybdate
Sodium tungstate
Other cations
 Potassium dichromate
Ammonium dichromate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Sodium dichromate is the inorganic compound with the formula Na2Cr2O7. However, the salt is usually handled as its dihydrate Na2Cr2O7·2H2O. Virtually all chromium ore is processed via conversion to sodium dichromate and virtually all compounds and materials based on chromium are prepared from this salt.[1] In terms of reactivity and appearance, sodium dichromate and potassium dichromate are very similar. The sodium salt is, however, around twenty times more soluble in water than the potassium salt (49 g/L at 0 °C) and its equivalent weight is also lower, which is often desirable.[2]

  1. ^ Gerd Anger, Jost Halstenberg, Klaus Hochgeschwender, Christoph Scherhag, Ulrich Korallus, Herbert Knopf, Peter Schmidt, Manfred Ohlinger, "Chromium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a07_067
  2. ^ Freeman, F. "Sodium Dichromate" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289X.