NH4MgPO46H2O

NH4MgPO4·6H2O, commonly known as struvite, is the mineral form of ammonium magnesium phosphate hexahydrate. It consists of ammonium (NH4+), magnesium (Mg2+), and phosphate (PO4^3-) ions coordinated with six water molecules. Struvite forms colorless to white crystals and is relatively soft. It is sparingly soluble in water and dissolves more readily under acidic conditions.

Struvite precipitates under conditions where magnesium, ammonium, and phosphate ions are available, typically at near-neutral to mildly basic pH. In natural and engineered systems, it can form in wastewater treatment plants, septic systems, and in the urinary tract of humans where bacteria produce urease, increasing local ammonia and pH. It is a common constituent of mineral deposits and scale in pipes.

In agriculture and wastewater management, struvite is of interest as a source of nitrogen, phosphorus, and magnesium. It can be recovered from wastewater as a potential slow-release fertilizer; industrial synthesis is also used to produce technical grades for fertilizer applications. Because it contains phosphate, its formation reduces dissolved phosphorus in water, contributing to phosphorus recovery strategies.

In medicine, struvite is a common composition of certain kidney stones (struvite stones), arising in the presence of urease-producing bacteria and alkaline urine.

Related terms include struvite as a mineral, magnesium ammonium phosphate, and phosphorus recovery in wastewater.