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| Names | |
|---|---|
| IUPAC name Nickel(II) nitrite | |
| Other names nickel dinitrite | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| RTECS number |
|
| UN number | 2726 |
| |
| |
| Properties | |
| Ni(NO2)2 | |
| Molar mass | 150.73 g/mol |
| Appearance | blue-green crystals |
| Density | 8.90 g/cm3 (20 °C)[dubious –discuss] |
| very soluble | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Nickel(II) nitrite is aninorganic compound with thechemical formula Ni(NO2)2.[1] Anhydrous nickel nitrite was first discovered in 1961 by Cyril Clifford Addison, who allowed gaseousnickel tetracarbonyl to react withdinitrogen tetroxide, yielding a green smoke. Nickel nitrite was the second transition element anhydrous nitrite discovered after silver nitrite.[2]
Nickel nitrite decomposes when heated to 220°C, however it can be heated up to 260°C in argon. The nitrite is covalently bonded to nickel, and the material is slightly volatile.[3] The infrared spectrum of the solid has absorption bands at 1575, 1388, 1333, 1240, 1080, and 830 cm−1.[3] Liquid dinitrogen tetroxide oxidises nickel nitrite tonickel nitrate.[3]
When nickel nitrite dissolves in water, different mixed nitro-aqua complexes form such as Ni(NO2)2(H2O)4,Ni(NO2)3(H2O)−3, andNi(NO2)(H2O)+5.[4]
The aqueous complex Ni(NO2)2(H2O)4 forms when an alkali metal nitrite is added to a nickel salt solution:
The complex is a much more intense emerald green colour than the Ni(H2O)62+ ion. Brooker claims that intense light photocatalyses the destruction of the ionic nitro complexes, leaving only Ni(NO2)2(H2O)4.[4]
Nickel nitrite slowly decomposes slightly in aqueous solution due todisproportionation:[4]
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In the presence of additional ligands, nickel nitrite can change colors substantially. These color changes may arise from the newmolecular orbitals, orlinkage isomerism, in which the nitro ligands rearrange to anitrito (-ONO) complex. Sorted by color, known compounds include:[5][6][7]
Thenitronickelates are related compounds where more nitro groups are attached to nickel to yield an anion. They could be described as nickel double nitrites.
