What is the density of krypton gas at STP?

The density of krypton gas at standard temperature and pressure is 3.749 g·L^−1. Krypton is a noble gas, which means it doesn't combine with other elements under normal circumstances.

Odorless, colorless, tasteless and nontoxic, krypton is obtained through the distillation of liquefied air. It is used in lighting and is famous for giving a brilliant white light in discharge tubes. It's sometimes combined with other gases to produce lights of different colors, and it is also used in krypton-fluoride lasers. An isotope of krypton, Kr-83, is used in MRI machines. Scientists believe that Earth's atmosphere contains krypton in about one part per million.