Ammonium dihydrogen phosphate Ammonium dihydrogen phosphate Ammonium dihydrogen phosphate (ADP), commonly called monoammonium phosphate (MAP) is a chemical compound with formula . It is a white crystalline solid consisting of ammonium cations and dihydrogen phosphate anions in equal proportions. ADP is a major ingredient of agricultural fertilizers and some fire extinguishers. It also has significant uses in optics and electronics. Monoammonium phosphate is soluble in water and crystallizes from it as the anhydrous salt in the tetragonal system, as elongated prisms or needles. It is practically insoluble in ethanol. Solid monoammonium phosphate can be considered stable in practice for temperatures up to 200
Dihydrogen complex some cases, hydrogen ligands are usefully characterized by X-ray crystallography, but often the presence of metals, which strongly scatter X-rays, complicates the analysis. The triangular MH subunit has six normal modes of vibration, one of which is mainly of ν character. In free H, this very strong bond absorbs at 4300 cm, whereas in dihydrogen complexes the frequency drops to around 2800 cm. Two preparation methods involve the direct reactions with H gas. The first entails the addition of H to an unsaturated metal center, as originally reported for W(CO)(P-i-Pr)(H). In such cases, the unsaturated complex in fact features an