Nickel hydroxide (Ni(OH)2) is a chemical compound that consists of nickel and hydroxide ions. It is commonly used as a precursor for nickel-based batteries.
| IUPAC name | Nickel hydroxide |
| Molecular formula | Ni(OH)2 |
| CAS number | 12054-48-7 |
| Synonyms | Nickel(II) hydroxide; Nickelous hydroxide; Dinitrogen nickel(2+) trioxide |
| InChI | InChI=1S/Ni.2H2O/h;2*1H2/q+2;;/p-2 |
Nickel Hydroxide Properties
Nickel Hydroxide Formula
The formula of Nickel Hydroxide is Ni(OH)2. It consists of one Nickel ion (Ni) and two Hydroxide ions (OH-). This chemical formula represents the composition of Nickel Hydroxide on an atomic level.
Nickel Hydroxide Molar Mass
The molar mass of Ni(OH)2 is calculated by adding the atomic masses of its constituent elements. Nickel has an atomic mass of 58.6934 g/mol, and each Hydroxide ion has a mass of 17.007 g/mol. Adding them together, the molar mass of Ni(OH)2 is approximately 92.6934 g/mol.
Nickel Hydroxide Boiling Point
Ni(OH)2 does not have a well-defined boiling point because it decomposes upon heating. At elevated temperatures, it undergoes thermal decomposition, converting into Nickel Oxide (NiO) and water vapor.
Nickel Hydroxide Melting Point
The melting point of Ni(OH)2 is approximately 230°C. At this temperature, Ni(OH)2 undergoes a phase change from a solid to a liquid state. The compound becomes molten, allowing for further chemical reactions or processing.
Nickel Hydroxide Density g/mL
The density of Ni(OH)2 is approximately 4.1 g/mL. This value represents the mass of the compound per unit volume. It indicates the compactness or concentration of Ni(OH)2 within a given space.
Nickel Hydroxide Molecular Weight
The molecular weight of Ni(OH)2 is determined by summing up the atomic weights of its constituent elements. Nickel has an atomic weight of 58.6934 g/mol, and each Hydroxide ion weighs 17.007 g/mol. Thus, the molecular weight of Ni(OH)2 is approximately 92.6934 g/mol.
Nickel Hydroxide Structure
Ni(OH)2 crystallizes in the hexagonal crystal system. It forms layers of Ni+2 and OH- ions stacked on top of each other. The Ni+2 ions are surrounded by OH- ions in a coordinated manner, creating a lattice structure.
Nickel Hydroxide Solubility
Ni(OH)2 is sparingly soluble in water. It dissolves to a limited extent, forming a slightly alkaline solution due to the presence of hydroxide ions. The solubility of Ni(OH)2 can be influenced by factors such as temperature and pH levels.
| Appearance | Green solid |
| Specific Gravity | 4.1 g/mL |
| Color | Green |
| Odor | Odorless |
| Molar Mass | 92.6934 g/mol |
| Density | 4.1 g/mL |
| Melting Point | 230°C |
| Boiling Point | Decomposes |
| Flash Point | N/A |
| Water Solubility | Slightly soluble |
| Solubility | Insoluble, forms alkaline solution in water |
| Vapour Pressure | N/A |
| Vapour Density | N/A |
| pKa | N/A |
| pH | Alkaline |
Nickel Hydroxide Safety and Hazards
Ni(OH)2 poses certain safety hazards that need to be taken into consideration. It can irritate the skin, eyes, and respiratory system upon contact or inhalation. Prolonged or repeated exposure may lead to sensitization, causing allergic reactions. It is important to handle Ni(OH)2 with care, using appropriate protective measures such as gloves, goggles, and a respirator. In case of accidental ingestion or exposure, immediate medical attention should be sought. Additionally, Ni(OH)2 is considered an environmental hazard and should be properly disposed of according to regulations to prevent contamination of soil or water sources.
| Hazard Symbols | None |
| Safety Description | – May cause skin and eye irritation\n- May cause respiratory irritation\n- Sensitization possible\n- Follow proper handling and disposal procedures |
| UN IDs | Not applicable |
| HS Code | 2825.70.10 |
| Hazard Class | Not classified as hazardous |
| Packing Group | Not applicable |
| Toxicity | Considered low to moderate toxicity |
Please note that the hazard symbols and UN IDs are not applicable for Ni(OH)2 as it is not classified as a hazardous substance. The provided safety description highlights the potential risks and precautions associated with handling Ni(OH)2. The toxicity of Ni(OH)2 is generally considered to be low to moderate.
Nickel Hydroxide Synthesis Methods
There are several synthesis methods available for the production of Ni(OH)2. One common method involves the reaction between a soluble nickel salt, such as nickel sulfate or nickel nitrate, and an alkali hydroxide, typically sodium hydroxide or potassium hydroxide. The reaction takes place in an aqueous solution under controlled conditions, resulting in the formation of Ni(OH)2 as a precipitate.
In the electrochemical deposition method, the electrolytic cell utilizes nickel metal as an electrode. It applies a suitable electric current to reduce nickel ions from the electrolyte and deposit them onto the electrode as Ni(OH)2. This method allows for precise control over the composition and morphology of the resulting Ni(OH)2.
Thermal decomposition of nickel salts enables the production of Ni(OH)2. By heating a nickel salt, such as nickel carbonate or Ni(OH)2 itself, in a controlled environment, the compound undergoes decomposition, yielding Ni(OH)2 along with other byproducts.
It’s worth mentioning that the choice of synthesis method depends on factors such as desired purity, particle size, and specific application requirements. When selecting the appropriate synthesis route for Ni(OH)2 production, one must carefully consider the desired outcome due to the advantages and limitations associated with each method.
Nickel Hydroxide Uses
Ni(OH)2 finds various applications due to its unique properties. Here are some common uses of Ni(OH)2:
- Battery manufacturing: Ni(OH)2 plays a crucial role as the cathode material in nickel-based batteries, such as nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries. It stores and releases electrical energy, enabling efficient energy storage.
- Catalyst: Ni(OH)2 acts as a catalyst in various chemical reactions, including hydrogenation and oxidation processes. Its catalytic properties facilitate the efficient conversion of reactants into desired products.
- Electroplating: Ni(OH)2 forms a stable and adherent layer of nickel, making it valuable in electroplating applications. It provides a protective, corrosion-resistant, and aesthetically appealing coating on different metal surfaces.
- Pigments: Manufacturers use Ni(OH)2 as a green pigment in the production of ceramics, glass, and plastics. Its vibrant green color enhances the aesthetic value of these materials.
- Gas sensors: Ni(OH)2-based sensors detect and monitor gases like hydrogen, ammonia, and hydrogen sulfide. The electrical conductivity changes in Ni(OH)2 films enable the detection of these gases effectively.
- Water treatment: Ni(OH)2 aids in water treatment processes by selectively adsorbing and removing heavy metal contaminants, such as lead and cadmium. It exhibits an affinity for these metals, making it useful for their removal from water sources.
- Pharmaceutical applications: Ni(OH)2 finds application in pharmaceutical formulations, serving as a binder, disintegrant, or pH regulator in tablet or capsule formulations.
These are just a few examples of the diverse applications of Ni(OH)2, showcasing its versatility and significance in various industries.
Questions:
Q: What is the chemical formula for the base nickel(II) hydroxide?
A: The chemical formula for nickelous(II) hydroxide is Ni(OH)2.
Q: Is nickel hydroxide soluble in water?
A: Ni(OH)2 is insoluble in water.
Q: How many grams of nickel(II) chloride are required to neutralize 75.0 mL of 0.555 M lithium hydroxide?
A: The grams of nickelous chloride required can be calculated using stoichiometry and the molarity of lithium hydroxide solution.
Q: What charge is Ni(OH)2?
A: The charge of Ni(OH)2 is neutral or zero.
Q: How to calculate molar solubility for Ni(OH)2?
A: Molar solubility of Ni(OH)2 can be determined by dividing the number of moles of dissolved compound by the volume of the solution.
Q: What is the balanced form of the equation NaOH(aq) + NiCl2(aq) → NaCl(aq) + Ni(OH)2(s)?
A: The balanced equation is 2NaOH(aq) + NiCl2(aq) → 2NaCl(aq) + Ni(OH)2(s).
Q: How many grams per mole is Ni(OH)2?
A: The molar mass of Ni(OH)2 is approximately 92.6934 g/mol.
Q: Is Ni(OH)2 soluble in water?
A: No, Ni(OH)2 is insoluble in water.
Q: What is the reducing agent in the reaction: Mg + NiO2 + 2H2O → Mg(OH)2 + Ni(OH)2?
A: The reducing agent in the reaction is magnesium (Mg).
Q: Is Ni(OH)2 a solid?
A: Yes, Ni(OH)2 is a solid compound.
Q: If the cell has a potential of 0.247 V at 25°C, what is the Ksp of Ni(OH)2?
A: The Ksp of Ni(OH)2 can be determined using the Nernst equation and the cell potential.
Q: Which salts will be more soluble in an acidic solution than in pure water?
A: Salts like Ni(OH)2 will be more soluble in an acidic solution due to the neutralization reaction with the acid.