| Names | |
|---|---|
| IUPAC name | |
| Other names Nickel hydroxide, Theophrastite | |
| Identifiers | |
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| ChemSpider | |
| ECHA InfoCard | 100.031.813 |
| EC Number |
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| RTECS number | |
CompTox Dashboard(EPA) | |
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| Properties | |
| Ni(OH)2 | |
| Molar mass | 92.724 g/mol (anhydrous) 110.72 g/mol (monohydrate) |
| Appearance | green crystals |
| Density | 4.10 g/cm3 |
| Melting point | 230 °C (446 °F; 503 K) (anhydrous, decomposes) |
| 0.13 g/L | |
| +4500.0·10−6 cm3/mol | |
| Structure[1] | |
| hexagonal, hP3 | |
| P3m1, No. 164 | |
α = 90°, β = 90°, γ = 120° | |
| Thermochemistry | |
| 79 J·mol−1·K−1[2] | |
Std enthalpy of formation(ΔfH⦵298) | −538 kJ·mol−1[2] |
| Hazards | |
| Safety data sheet | External SDS |
| GHS pictograms | [3] |
| GHS Signal word | Danger[3] |
| H302, H332, H315, H334, H317, H341, H350, H360, H372[3] | |
| P260, P284, P201, P280, P405, P501[3] | |
| Lethal dose or concentration (LD, LC): | |
| 1515 mg/kg (oral, rat) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| verify (what is ?) | |
| Infobox references | |
Nickel(II) hydroxide is the inorganic compound with the formula Ni(OH)2. It is an apple-green solid that dissolves with decomposition in ammonia and amines and is attacked by acids. It is electroactive, being converted to the Ni(III) oxy-hydroxide, leading to widespread applications in rechargeable batteries.[4]
Properties[edit]
To calculate molecular weight of a chemical compound enter it's formula, specify its isotope mass number after each element in square brackets. 分子量计算的例子： C14O162, S34O162. ››More information on molar mass and molecular weight. In chemistry, the formula weight is a quantity computed by multiplying the atomic weight (in atomic mass units) of each element in a chemical formula by the number of atoms of that element present in the formula, then adding all. Nickel(II) Hydroxide Ni(OH)2 Molar Mass, Molecular Weight.
Nickel(II) hydroxide has two well-characterized polymorphs, α and β. The α structure consists of Ni(OH)2 layers with intercalated anions or water.[5][6] The β form adopts a hexagonal close-packed structure of Ni2+ and OH− ions.[5][6] In the presence of water, the α polymorph typically recrystallizes to the β form.[5][7] In addition to the α and β polymorphs, several γ nickel hydroxides have been described, distinguished by crystal structures with much larger inter-sheet distances.[5]
The mineral form of Ni(OH)2, theophrastite, was first identified in the Vermion region of northern Greece, in 1980. It is found naturally as a translucent emerald-green crystal formed in thin sheets near the boundaries of idocrase or chlorite crystals.[8] A nickel-magnesium variant of the mineral, (Ni,Mg)(OH)2 had been previously discovered at Hagdale on the island of Unst in Scotland.[9]
Reactions[edit]
Nickel(II) hydroxide is frequently used in electrical car batteries.[6] Specifically, Ni(OH)2 readily oxidizes to nickel oxyhydroxide, NiOOH, in combination with a reduction reaction, often of a metal hydride (reaction 1 and 2).[10]
Reaction 1 Ni(OH)2 + OH− → NiO(OH) + H2O + e−
Reaction 2 M + H2O + e− → MH + OH−
Net Reaction (in H2O)Ni(OH)2 + M → NiOOH + MH
Of the two polymorphs, α-Ni(OH)2 has a higher theoretical capacity and thus is generally considered to be preferable in electrochemical applications. However, it transforms to β-Ni(OH)2 in alkaline solutions, leading to many investigations into the possibility of stabilized α-Ni(OH)2 electrodes for industrial applications.[7]
Synthesis[edit]
The synthesis entails treating aqueous solutions of nickel(II) salts with potassium hydroxide.[11]
Toxicity[edit]
The Ni2+ ion is a known carcinogen. Toxicity and related safety concerns have driven research into increasing the energy density of Ni(OH)2 electrodes, such as the addition of calcium or cobalt hydroxides.[4]
See also[edit]
References[edit]
- ^Enoki, Toshiaki; Tsujikawa, Ikuji (1975). 'Magnetic Behaviours of a Random Magnet, NipMg(1-p)(OH2)'. Journal of the Physical Society of Japan. 39 (2): 317. doi:10.1143/JPSJ.39.317.
- ^ abZumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A22. ISBN978-0-618-94690-7.
- ^ abcd'Nickel Hydroxide'. American Elements. Retrieved 2018-08-30.
- ^ abChen, J.; Bradhurst, D.H.; Dou, S.X.; Liu, H.K. (1999). 'Nickel Hydroxide as an Active Material for the Positive Electrode in Rechargeable Alkaline Batteries'. J. Electrochem. Soc. 146 (10): 3606–3612. doi:10.1149/1.1392522.
- ^ abcdOliva, P.; Leonardi, J.; Laurent, J.F. (1982). 'Review of the structure and the electrochemistry of nickel hydroxides and oxy-hydroxides'. Journal of Power Sources. 8 (2): 229–255. doi:10.1016/0378-7753(82)80057-8.
- ^ abcJeevanandam, P.; Koltypin, Y.; Gedanken, A. (2001). 'Synthesis of Nanosized α-Nickel Hydroxide by a Sonochemical Method'. Nano Letters. 1 (5): 263–266. doi:10.1021/nl010003p.
- ^ abShukla, A.K.; Kumar, V.G.; Munichandriah, N. (1994). 'Stabilized α-Ni(OH)2 as Electrode Material for Alkaline Secondary Cells'. J. Electrochem. Soc. 141 (11): 2956–2959. doi:10.1149/1.2059264.
- ^Marcopoulos, T.; Economou, M. (1980). 'Theophrastite, Ni(OH)2, a new mineral from northern Greece'(PDF). American Mineralogist. 66: 1020–1021.
- ^Livingston, A.; Bish, D. L. (1982). 'On the new mineral theophrastite, a nickel hydroxide, from Unst, Shetland, Scotland'(PDF). Mineralogical Magazine. 46 (338): 1. doi:10.1180/minmag.1982.046.338.01.
- ^Ovshinsky, S.R.; Fetcenko, M.A.; Ross, J. (1993). 'A nickel metal hydride battery for electric vehicles'. Science. 260 (5105): 176–181. doi:10.1126/science.260.5105.176. PMID17807176.
- ^Glemser, O. (1963) 'Nickel(II) Hydroxide' in 'Handbook of Preparative Inorganic Chemistry, 2nd ed. G. Brauer (ed.), Academic Press, NY. Vol. 1. p. 1549.