* Argon (Ar)
* Nitrogen (N2)
* Krypton (Kr)
The specific composition of the gas mixture depends on the desired properties of the lamp, such as its color temperature and lifespan.
Halogens themselves are not used to fill halogen lamps. The term "halogen" refers to the presence of a small amount of a halogen gas like iodine (I2) or bromine (Br2) within the lamp. These halogens play a crucial role in the lamp's operation by participating in a chemical cycle that allows the tungsten filament to evaporate and redeposit, extending the lamp's lifespan.
Therefore, while the lamp is called a "halogen lamp," the majority of the gas inside is a mixture of inert gases, and the halogen gas is present only in small amounts.
