Definition that contains onium compound
- nitrification the oxidation of ammonium compounds in dead organic material into nitrates and nitrites by soil bacteria (making nitrogen available to plants)
- nitrobacterium any of the bacteria in the soil that take part in the nitrogen cycle; they oxidize ammonium compounds into nitrites or oxidize nitrites into nitrates
- ammonium carbonate a carbonate of ammonium; used in the manufacture of smelling salts and baking powder and ammonium compounds