Barium chromate is a fine light yellow powder with the formula BaCrO₄. The chromium occurs in the +6 oxidation state

Oxidation state

In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...

. It is an oxidizing agent, and produces a green flame when heated, the result of barium ions.

Reactions

It is very insoluble

Solubility

Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...

 in water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

, 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 composition
  Pyrotechnic composition
  A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas or smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions...
  
  s, especially delay composition
  Delay composition
  Delay composition, also called delay charge or delay train, is a pyrotechnic composition, a sort of pyrotechnic initiator, a mixture of oxidizer and fuel that burns in a slow, constant rate that should not be significantly dependent on temperature and pressure. Delay compositions are used to...
  
  s.
• As a pigment
  Pigment
  A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
  
   in paints, ceramics, coloring glasses, fuses, and porcelain
  Porcelain
  Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...
  
  s.
• As a corrosion inhibitor
  Corrosion inhibitor
  A corrosion inhibitor is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal or an alloy. The effectiveness of a corrosion inhibitor depends on fluid composition, quantity of water, and flow regime...
  
   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

Toxicity

Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...

. Chromates, when pulverized and inhaled, are carcinogen

Carcinogen

A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...

s.