It is stable at room temperature and pressure, but avoids contact with oxides and strong acids. However, it is thermally unstable, decomposing at 60°C in solid form and 70°C in aqueous solution.
The solubility in water is 14% at 10°C, 17.4% at 20°C, and 21.3% at 30°C. Its aqueous solution is alkaline, with a pH of 7.8 for a 0.1 mol·L⁻¹ solution at 25°C. Ammonium bicarbonate is chemically unstable and readily decomposes upon heating. When heated to approximately 60°C, it decomposes into white smoke composed of 21.5% NH₃, 55.7% CO₂, and 22.8% H₂O. It can be decomposed by hot water, an endothermic reaction. In the presence of moisture at normal pressure, it begins to slowly decompose above 36°C, producing ammonia, carbon dioxide, and water.
