Copper(I) chloride
Copper(I) chloride is white when pure. It does not dissolve in water. It is green when in air because of conversion to copper(II) chloride. It can react with Lewis bases, a group of chemicals. It dissolves in hydrochloric acid easily. It dissolves in solutions that have ammonia in them. It absorbs carbon monoxide. It easily disproportionates into copper and copper(II) chloride. It reacts with ammonia and acetylene to make copper(I) acetylide, a reddish explosive.