Here's a breakdown:

* Na₂CO₃: This represents Sodium Carbonate, a common inorganic compound.

* 4H₂O: This indicates that four molecules of water are associated with each molecule of Sodium Carbonate. The "dot" (.) signifies that these water molecules are bound to the sodium carbonate in a crystalline structure.

Sodium Carbonate Decahydrate is a crystalline solid that is commonly used in various applications, including:

* Water Softening: It helps remove calcium and magnesium ions from hard water.

* Cleaning and Detergents: It acts as a cleaning agent in detergents and household cleaners.

* Glass Manufacturing: It is a key ingredient in the production of glass.

* Food Industry: It is used as a food additive, primarily as a leavening agent and pH regulator.

It's important to note that the hydrated form (Na₂CO₃.4H₂O) is less stable than the anhydrous form (Na₂CO₃) and can easily lose its water molecules upon heating or exposure to dry air.