Simplify the following text for a Grade 4 native English-speaking person.
Original: For example , the creation of argon fluorohydride ( HArF ) , a marginally stable compound of argon with fluorine and hydrogen , was reported by researchers at the University of Helsinki in 2000 . Although the neutral ground-state chemical compounds of argon are presently limited to HArF , argon can form clathrates with water when atoms of it are trapped in a lattice of the water molecules .
Simplified: Argon atoms are found in air .