When heating up a chlorine compound with other Martian soils, Curiosity discovered that the compound reacted with carbon to form a simple organic.

FORBES: Curiosity Finds Hint Of Carbon On Mars

In China, they use artillery shells, rockets and airplanes to spray existing cloud systems with silver iodide, a compound that triggers moisture in the clouds to form ice crystals, which then fall to earth as snow or rain.

WSJ: Blizzard Renews Storm Over China Making Snow

One company exploits this phenomenon by making nanoparticles of the compound cerium oxide, which in that form are chemically reactive enough to serve as a catalyst.

ECONOMIST: Small wonders