Barium chromate
| Names | |
|---|---|
| IUPAC name
Barium chromate
| |
| Other names
Barium chromate oxide
Barium tetraoxochromate(VI) | |
| Properties | |
| BaCrO4 | |
| Molar mass | 253.37 g/mol |
| Appearance | Yellow solid |
| Odor | Odorless |
| Density | 4.498 g/cm3 (20 °C) |
| Melting point | 210–1,380 °C (410–2,516 °F; 483–1,653 K) (decomposition) |
| Boiling point | Decomposes |
| 0.0002775 g/100 ml (20 °C) | |
| Solubility | Soluble in strong acids |
| Vapor pressure | ~0 mmHg |
| Thermochemistry | |
| Std molar
entropy (S |
172 J·mol-1·K-1 |
| Std enthalpy of
formation (ΔfH |
-1,429 kJ/mol |
| Hazards | |
| Safety data sheet | LobaChemie |
| Flash point | Non-flammable |
| Related compounds | |
| Related compounds
|
Potassium chromate Sodium chromate |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Barium chromate or barium tetraoxochromate(VI) is a yellow solid compound with the chemical formula BaCrO4.
It can be found in nature as the mineral Hashemite, although the natural mineral often has sulfur in its composition.
Contents
Properties
Chemical
Barium chromate react with barium hydroxide in the presence of sodium azide to create barium chromate(V). The reaction releases oxygen and water.
- BaCrO4 + Ba(OH)2 → 2 Ba3(CrO4)2 + O2 + 2 H2O
Physical
Barium chromate is a yellowish powdered solid, practically insoluble in water, but more soluble in conc. acids.
Availability
Barium chromate is sold by chemical suppliers.
Preparation
Barium chromate can be prepared by adding a solution of a soluble barium salt, like barium chloride, to a solution of potassium or sodium chromate:
- BaCl2 + K2CrO4 → BaCrO4 + 2 KCl
- BaCl2 + Na2CrO4 → BaCrO4 + 2 NaCl
The resulting barium chromate precipitates out of the solution as an insoluble yellow powder.
Projects
- Compound collecting
- Yellow paint
- Sulfate scavenger in chromium electroplating baths
- Oxidizing agent in pyrotechnic mixtures
- Corrosion inhibition pigment
- Catalyst for alkane dehydrogenation
Handling
Safety
Barium chromate is toxic if ingested or inhaled. It is genotoxic and cytotoxic, as chromates are confirmed carcinogens.
Storage
In closed plastic bottles.
Disposal
Can be taken to hazardous waste companies.
Alternatively, one can convert the compound to barium sulfate, while the Cr(VI) can be reduced to Cr(III). The neutralization products can then be dumped in trash.
