Manganese(II) nitrate refers to the inorganic compounds with formulaMn(NO3)2·(H2O)n. These compounds are nitrate salts containing varying amounts of water. A common derivative is the tetrahydrate, Mn(NO3)2·4H2O, but mono- and hexahydrates are also known as well as the anhydrous compound. Some of these compounds are useful precursors to the oxides of manganese.[1] Typical of a manganese(II) compound, it is a paramagnetic pale pink solid.
Structure
Manganese(II) compounds, especially with oxygenated ligands, are typically octahedral. Following this trend, the tetrahydrate features four aquo ligands bound to Mn as well as two mutually cis, unidentate nitrate ligands.[2] The hexaaquo salt features octahedral [Mn(H2O)6]2+.[3]
In this redox reaction, two moles of the reductantNO2 (gas) donate each one electron to MnO2 (black solid), the oxidant, which is reduced from its oxidation state (IV) to its lower state (II). Simultaneously, NO2 (IV) is oxidized to form nitrate (NO−3) (V).
Heating the tetrahydrate to 110 °C gives the pale yellow monohydrate.[4]
The reaction is reversible in the sense that heating the Mn(II) dinitrate to 450°C gives a slightly nonstoichiometric Mn(IV) dioxide.[5]
^"The Crystal Structure of Manganese Nitrate Tetrahydrate Mn(NO3)2·4H2O". Zeitschrift für Kristallographie - Crystalline Materials. 137 (4): 280–289. 1973. doi:10.1524/zkri.1973.137.4.280.
^Petrovič, D.; Ribár, B.; Djurič, S.; Krstanovič, I. (1976). "The Crystal Structure of Hexaquomanganese Nitrate, Mn(OH2)6(NO3)2". Zeitschrift für Kristallographie - Crystalline Materials. 144 (1–6): 334–340. doi:10.1524/zkri.1976.144.16.334. S2CID97491858.
^Milinski, N.; Ribár, B.; Ćulum, Ž.; Djurić, S. (1977). "The Crystal Structure of Manganese Nitrate Monohydrate". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 33 (6): 1678–1682. doi:10.1107/S056774087700689X.
^Lux H. (1963). "Manganeses(II) Oxide". In Brauer G. (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. New York: Academic Press. p. 1455.