Barium chromate

Barium chromate
Other names Barium chromate oxide, Chromic acid, (H2CrO4), barium salt (1:1)
Identifiers
CAS number	10294-40-3 Y
PubChem	25136
ChemSpider	23481 Y
RTECS number	CQ876000
Jmol-3D images	Image 1
SMILES [Ba+2].[O-][Cr]([O-])(=O)=O
InChI InChI=1S/Ba.Cr.4O/q+2;;;;2*-1 Y Key: QFFVPLLCYGOFPU-UHFFFAOYSA-N Y InChI=1/Ba.Cr.4O/q+2;;;;2*-1/rBa.CrO4/c;2-1(3,4)5/q+2;-2 Key: QFFVPLLCYGOFPU-XPTLYTIWAW
Properties
Molecular formula	BaCrO4
Molar mass	253.37 g/mol
Appearance	yellow powder
Density	4.498 g/cm3
Melting point	210 °C, decomposes
Solubility in water	0.0002775 g/100 mL (20 °C)
Hazards
MSDS	External MSDS
EU classification	Harmful (Xn)
R-phrases	R20/22
S-phrases	(S2), S28
NFPA 704	0 3 3
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Barium chromate is a fine light yellow powder with the formula BaCrO₄. The chromium occurs in the +6 oxidation state. It is an oxidizing agent, and produces a green flame when heated, the result of barium ions.

Reactions

It is very insoluble in water, but is soluble in acids:

2 BaCrO₄ + 2 H⁺   →   2 Ba²⁺ + Cr₂O₇^2- + H₂O

K_sp = [Ba²⁺][CrO₄^2-] = 2.1 x 10^-10

Uses

There are a few uses of barium chromate:

• As an oxidizer and/or burn rate modifier in some pyrotechnic compositions, especially delay compositions.
• As a pigment in paints, ceramics, coloring glasses, fuses, and porcelains.
• As a corrosion inhibitor to prevent electrochemical corrosion at the joints of dissimilar metals.
• In safety matches.
• In metal primers.
• In ignition control devices.
• As an initiator for explosives.

Safety

Barium chromate is toxic. Chromates, when pulverized and inhaled, are carcinogens.

References

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