Potassium chromate

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Potassium chromate
Identifiers
CAS number7789-00-6 YesY
PubChem24597
EC number232-140-5
ChEBICHEBI:75249 N
RTECS numberGB2940000
Jmol-3D imagesImage 1
Properties
Molecular formulaCrK2O4
Molar mass194.19 g mol−1
AppearanceYellow powder
Odorodorless
Density2.7320 g/cm3
Melting point968 °C; 1,774 °F; 1,241 K
Boiling point1,000 °C; 1,830 °F; 1,270 K
Solubility in water62.9 g/100 mL (20 °C)

75.1 g/100 mL (80 °C)
79.2 g/100 mL (100 °C)
Solubilityinsoluble in alcohol
Refractive index (nD)1.74
Structure
Crystal structurerhombic
Hazards
MSDSChemical Safety Data
EU Index024-006-00-8
EU classificationCarc. Cat. 2
Muta. Cat. 2
Toxic (T)
Irritant (Xi)
Dangerous for the environment (N)
R-phrasesR49, R46, R36/37/38, R43, R50/53
S-phrasesS53, S45, S60, S61
NFPA 704
NFPA 704.svg
0
3
1
OX
Related compounds
Other anionsPotassium dichromate
Potassium molybdate
Potassium tungstate
Other cationsSodium chromate
Calcium chromate
Barium chromate
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references
 
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Potassium chromate
Identifiers
CAS number7789-00-6 YesY
PubChem24597
EC number232-140-5
ChEBICHEBI:75249 N
RTECS numberGB2940000
Jmol-3D imagesImage 1
Properties
Molecular formulaCrK2O4
Molar mass194.19 g mol−1
AppearanceYellow powder
Odorodorless
Density2.7320 g/cm3
Melting point968 °C; 1,774 °F; 1,241 K
Boiling point1,000 °C; 1,830 °F; 1,270 K
Solubility in water62.9 g/100 mL (20 °C)

75.1 g/100 mL (80 °C)
79.2 g/100 mL (100 °C)
Solubilityinsoluble in alcohol
Refractive index (nD)1.74
Structure
Crystal structurerhombic
Hazards
MSDSChemical Safety Data
EU Index024-006-00-8
EU classificationCarc. Cat. 2
Muta. Cat. 2
Toxic (T)
Irritant (Xi)
Dangerous for the environment (N)
R-phrasesR49, R46, R36/37/38, R43, R50/53
S-phrasesS53, S45, S60, S61
NFPA 704
NFPA 704.svg
0
3
1
OX
Related compounds
Other anionsPotassium dichromate
Potassium molybdate
Potassium tungstate
Other cationsSodium chromate
Calcium chromate
Barium chromate
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Potassium chromate (K2CrO4) is a yellow chemical indicator used for identifying concentrations of chloride ions in a salt solution with silver nitrate (AgNO3). It is a class two carcinogen and can cause cancer on inhalation.[1]

General information[edit]

Physical properties[edit]

Potassium Chromate is a lemon-colored compound that is in the form of a crystalline solid, and it is very stable.[citation needed]

Production[edit]

It is prepared by roasting powdered chromite with potash and limestone, treating the cinder with a hot potassium sulfate solution and leaching.

Alternatively, it may be prepared by the reaction of potassium dichromate and potassium hydroxide.

Reactions[edit]

When reacted with lead(II) nitrate, it creates an orange-yellow precipitate, lead(II) chromate. All ions hydrolyze in solution[citation needed].

Applications[edit]

It is used as a mordant in dyeing fabrics, as a tanning agent in the leather industry, in bleach oils and waxes, and as an oxidizing agent in organic synthesis.

Occurrence[edit]

Tarapacaite is the natural, mineral form of potassium chromate. It occurs very rarely and until now is known from only few localities on Atacama desert.[citation needed]

Safety[edit]

Potassium chromate is very toxic and may be fatal if swallowed. It may also act as a carcinogen, and can create reproductive defects if inhaled or swallowed. It also is a strong oxidizing agent if in the presence of H+ to produce the dichromate ion. It may react rapidly, or violently. It is also possible that it may react explosively with other reducing agents and flammable objects.

References[edit]

  1. ^ Potassium chromate information URL last accessed 15 March 2007