Nickel (II) hydroxide
|__ Ni 2+ __ OH -|
|Surname||Nickel (II) hydroxide|
|Ratio formula||Ni (OH) 2|
apple green powder
|External identifiers / databases|
|Molar mass||92.71 g mol −1|
4.1 g cm −3
230 ° C (decomposes to nickel (II) oxide)
practically insoluble in water (0.13 g l −1 at 20 ° C)
|As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .|
Of course, nickel (II) hydroxide occurs in the form of the very rare mineral theophrastite .
Extraction and presentation
Nickel (II) hydroxide is formed when nickel ions are detected from nickel salt solutions with sodium hydroxide solution as a precipitate with a clear green color:
- Nickel (II) ions from nickel salt solutions (such as nickel (II) chloride dissolved in water ) react with caustic soda to form green, water-insoluble nickel (II) hydroxide and sodium ions.
- Nickel (II) ions react with excess ammonia to form blue, water-soluble hexaammine nickel (II) ions and hydroxide ions.
- Green nickel (II) hydroxide reacts with bromine to form black, water-insoluble nickel (IV) oxide and hydrogen bromide .
Electrolytic oxidation turns nickel (II) hydroxide into nickel (III) oxide or nickel (III) oxide hydroxide. This reversible process is important for the nickel-cadmium accumulator and the nickel-iron accumulator .
With 3Ni (OH) 2 2H 2 O there is also a green hydrate that is stable in the dry state.
Nickel (II) hydroxide is used for electroplating, as the main component for plates of alkaline accumulators (see nickel-iron accumulator , nickel-cadmium accumulator , nickel-hydrogen accumulator and nickel-metal hydride accumulator ) and for the production of nickel catalysts.
Like many nickel compounds, nickel (II) hydroxide is classified as carcinogenic (Category 1A), toxic to reproduction (Category 1B) and germ cell mutagenic (Category 2). In addition, nickel (II) hydroxide has a sensitizing effect.
- Entry on nickel dihydroxide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
- Data sheet nickel (II) hydroxide (PDF) from Fisher Scientific , accessed on February 13, 2014.
- Mineralienatlas.de: Theophrastit
- Georg Brauer (ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1691.
- Swiss Confederation: Products of the chemical industry or related industries ( Memento of the original of February 6, 2012 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.