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Date: 7-12-2018
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Date: 25-11-2018
790
Date: 30-3-2019
1058
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Thermal decomposition of Ni(OH)2, NiCO3, or NiNO3 generates NiO.
Formula | Color | Oxidation State | MP | Structure / comments |
---|---|---|---|---|
NiO | green powder | Ni2+ | 1955 | NaCl |
Nickel sulfides consist of NiS2, which has a pyrite structure, and Ni3S4, which has a spinel structure.
All the nickel dihalides are known to exist. These compounds are usually yellow to dark brown in Color. Preparation directly from the elements is possible for all except NiF2, which is best prepared from reaction of F2on NiCl2 at 350°C. Most are soluble in water and crystallization of the hexahydrate containing the [Ni(H2O)6]2+ion can be achieved. NiF2however is only slightly soluble in water from which the trihydrate crystallizes. The only nickel trihalide known to exist is an impure specimen of NiF3.
Formula | Color | MP | μ (BM) | Structure |
---|---|---|---|---|
NiF2 | yellow | 1450 | 2.85 | tetragonal rutile |
NiCl2 | yellow | 1001 | 3.32 | CdCl2 |
NiBr2 | yellow | 965 | 3.0 | CdCl2 |
NiI2 | Black | 780 | 3.25 | CdCl2 |
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