Ammonium chromate

Ammonium chromate is a salt with the formula (NH4)2CrO4. It forms yellow, monoclinic crystals; made from ammonium hydroxide and ammonium dichromate; used in photography as a sensitizer for gelatin coatings. It is often used in photography, textile printing, and fixing chromate dyes on wool. It is also used as an analytical reagent, catalyst, and corrosion inhibitor. It is soluble in water, and, when applied, can cause irritation in the mucous membrane, eyes, respiratory tract, skin, etc. It may cause skin sensitization after prolonged contact. It is also known to be carcinogenic (cancer-causing), and it can cause tissue ulceration and injury to the liver and kidneys.

Ammonium chromate
Names
Other names
Ammonium chromate(IV)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.217
EC Number
  • 232-138-4
PubChem CID
UNII
UN number 3085,3077
  • InChI=1S/Cr.2H3N.4O/h;2*1H3;;;;/q;;;;;2*-1/p+2
    Key: MFFLHUNPSHBKRG-UHFFFAOYSA-P
SMILES
  • [NH4+].[NH4+].[O-][Cr](=O)(=O)[O-]
Properties
(NH4)2CrO4
Molar mass 152.07 g/mol
Appearance yellow crystals
Density 1.90 g/ml
Melting point 185 °C (365 °F; 458 K) decomposes
24.8 g/100ml (0 °C)
37.36 g/100ml (25 °C)
45.3 g/100ml (40 °C)
70.06 g/100ml (75 °C)
Thermochemistry
Std molar
entropy (S298)
657 J/K·mol
Std enthalpy of
formation fH298)
-1163 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Toxic
GHS labelling:
Danger
H272, H314, H317, H334, H350, H400
P201, P220, P261, P273, P280, P305+P351+P338
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
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