Premium Ammonium CMC Powder - Cost-Efficient SCR Catalyst Binder (Ready to Ship) CMC-NH4 stands for Ammonium Carboxymethyl Cellulose. It is a water-soluble cellulose derivative where the hydrogen ions of the carboxymethyl groups are neutralized by ammonium ions. Unlike the more common Sodium Carboxymethyl Cellulose (CMC-Na), CMC-NH4 is specially valued in high-tech and high-purity applications because it leaves virtually no metal ash or residual alkali metal salts upon