Here's a breakdown:

* Ba: Barium, an alkaline earth metal

* H: Hydrogen

* P: Phosphorus

* O₄: Four oxygen atoms

Barium hydrogen phosphate is a white, crystalline solid that is used in various applications, including:

* Pigments: It is used in the production of white pigments.

* Fireworks: Barium compounds are used in fireworks to produce green colors.

* Phosphate fertilizers: It can be used as a source of phosphorus for plant growth.

Note: Barium compounds are toxic, and it is important to handle them with care.