With its striking metallic luster and vivid golden hues, nickel II sulfide is a compound that captures attention. But beyond its flashy appearance lies an intricate chemical structure that provides valuable insights into the quantum mechanical world.

In this comprehensive guide, we’ll explore the nickel II sulfide formula, looking at the compound’s composition, structure, properties, uses, and fascinating quantum mechanical quirks.

If you’re short on time, here’s a quick answer to your question: the chemical formula for nickel II sulfide is NiS.

The Composition and Chemical Formula of Nickel II Sulfide

Nickel II sulfide, also known as nickelous sulfide, is a chemical compound composed of nickel and sulfur atoms. It is represented by the chemical formula NiS. The compound is formed when nickel, a transition metal, bonds with sulfur, a non-metal, through a covalent bond.

Defining Nickel II Sulfide

Nickel II sulfide is a solid black compound that is insoluble in water. It has a high melting point and is stable under normal conditions. This compound is commonly found in nature as a mineral called millerite.

Millerite is a rare nickel sulfide mineral that forms in hydrothermal deposits or in association with other nickel minerals.

Nickel II sulfide has various applications in industries. It is used in the production of batteries, specifically nickel-metal hydride (NiMH) batteries, where it serves as a cathode material. Additionally, it is utilized in the manufacturing of pigments, ceramics, and as a catalyst in chemical reactions.

Nickel II Sulfide Formula and Composition

The chemical formula of nickel II sulfide, NiS, signifies that the compound contains one atom of nickel (Ni) and one atom of sulfur (S). The atomic weight of nickel is approximately 58.69 grams per mole, while sulfur has an atomic weight of around 32.06 grams per mole.

When combined, the nickel and sulfur atoms form a lattice structure in which each nickel atom is surrounded by six sulfur atoms, creating a coordination number of 6. This arrangement is known as a hexagonal close-packed structure.

Nickel II Sulfide Nomenclature

The nomenclature of nickel II sulfide follows the rules of chemical naming. The term “nickel II” indicates that the compound contains nickel in its +2 oxidation state. The suffix “sulfide” denotes the presence of sulfur.

In chemical formulas, Roman numerals are used to indicate the oxidation state of the metal.

It is important to note that nickel II sulfide should not be confused with nickel sulfide, which can exist in multiple oxidation states, including nickel II and nickel III. The distinction is crucial, as the oxidation state affects the chemical properties and behavior of the compound.

For more detailed information on nickel II sulfide, you can refer to reputable sources such as the PubChem database or academic journals specializing in inorganic chemistry.

The Crystal Structure and Lattice of Nickel II Sulfide

Nickel II sulfide, also known as nickel sulfide or NiS, is a compound composed of nickel and sulfur. It has a distinct crystal structure and lattice that play a crucial role in its physical and chemical properties.

The Millerite Crystal Structure

The crystal structure of nickel II sulfide is commonly referred to as the Millerite structure. It belongs to the hexagonal crystal system and exhibits a unique arrangement of atoms. In this structure, each nickel atom is surrounded by six sulfur atoms, forming octahedral coordination.

Similarly, each sulfur atom is surrounded by three nickel atoms, resulting in trigonal prismatic coordination. This arrangement creates a highly stable lattice that contributes to the compound’s overall stability.

Lattice Constants and Unit Cell

The lattice constants of nickel II sulfide determine the size and shape of its unit cell, which is the basic repeating unit in its crystal structure. The lattice constants for nickel II sulfide are typically reported as a and c, representing the lengths of the hexagonal unit cell edges.

The unit cell of nickel II sulfide is often described as a hexagonal prism with a base that is an equilateral triangle and a height equal to c. These lattice constants and unit cell parameters provide valuable insights into the crystal symmetry and packing of atoms within the compound.

According to research published in the Journal of Physical Chemistry C, the lattice constants of nickel II sulfide are approximately a = 3.52 Å and c = 5.75 Å. These values may vary slightly depending on factors such as temperature and impurities present in the crystal lattice.

Coordination Geometry

The coordination geometry of nickel II sulfide refers to the arrangement of atoms surrounding each nickel or sulfur atom within the crystal lattice. As mentioned earlier, nickel atoms in nickel II sulfide exhibit octahedral coordination, meaning they are surrounded by six sulfur atoms.

On the other hand, sulfur atoms have trigonal prismatic coordination, with three nickel atoms in close proximity. This coordination geometry influences the compound’s chemical reactivity, as well as its physical properties such as hardness and electrical conductivity.

Understanding the crystal structure and lattice of nickel II sulfide is essential for studying its properties and applications in various fields, including materials science, catalysis, and electronics.

By examining the Millerite crystal structure, lattice constants, and coordination geometry, scientists can gain valuable insights into the behavior and characteristics of this fascinating compound.

Key Properties of Nickel II Sulfide

Physical Properties

Nickel II sulfide, also known as nickelous sulfide, is a chemical compound with the formula NiS. It is a solid, black or dark brown powder that is insoluble in water. The compound has a molecular weight of 90.76 g/mol and a density of 5.28 g/cm³.

Nickel II sulfide has a melting point of 797°C (1467°F) and a boiling point of 1180°C (2156°F).

When exposed to air, nickel II sulfide can slowly oxidize, forming nickel oxide on its surface. It is important to handle this compound with care to avoid inhalation or skin contact.

Chemical Properties

Nickel II sulfide is primarily used in the production of other nickel compounds and as a catalyst in various chemical reactions. It is a stable compound that does not decompose easily under normal conditions. However, it can react with strong acids to form soluble nickel salts.

One of the key reactions of nickel II sulfide is its ability to react with hydrogen gas to produce nickel metal and hydrogen sulfide gas. This reaction is often used in the industrial production of nickel metal.


Nickel II sulfide is considered to be a toxic substance. Inhalation or ingestion of the compound can lead to various health issues, including respiratory problems, skin irritation, and gastrointestinal effects.

Prolonged or repeated exposure to nickel II sulfide may also cause lung damage and can potentially be carcinogenic.

It is important to handle nickel II sulfide with caution and follow proper safety protocols when working with this compound. Protective equipment, such as gloves and respiratory masks, should be used to minimize exposure. In case of accidental exposure, immediate medical attention should be sought.

For more information on the properties and uses of nickel II sulfide, you can visit the PubChem website.

Applications and Uses of Nickel II Sulfide

Nickel II sulfide, with the chemical formula NiS, is a compound that finds various applications in different industries. Its unique properties make it a versatile material for several purposes. In this section, we will explore some of the key applications and uses of nickel II sulfide.


Nickel II sulfide is commonly used as a catalyst in various chemical reactions. It acts as a promoter or a catalyst support in processes such as hydrogenation and desulfurization. Its ability to enhance reaction rates and improve selectivity makes it an essential component in the production of chemicals, petroleum refining, and other industrial processes.

For example, in the petroleum industry, nickel II sulfide catalysts are used in hydrodesulfurization reactions to remove sulfur compounds from crude oil and reduce environmental pollution. These catalysts play a crucial role in ensuring the production of cleaner fuels.

Solar Cell Absorbers

Nickel II sulfide has also shown promise as a material for solar cell absorbers. Solar cells are devices that convert sunlight into electricity, and the efficiency of these cells depends on the quality of the absorber material used.

Nickel II sulfide, with its suitable bandgap and optical properties, has emerged as a potential candidate for solar cell applications.

Researchers are investigating various methods to enhance the efficiency and stability of nickel II sulfide-based solar cells. By optimizing the synthesis techniques and exploring different doping strategies, scientists aim to make nickel II sulfide a viable and cost-effective option for renewable energy production.

Luminescent Materials

Nickel II sulfide exhibits luminescent properties, making it valuable in the field of optoelectronics. Luminescent materials emit light when stimulated, and they find applications in areas such as lighting, displays, and sensors.

Researchers have been exploring the use of nickel II sulfide as a luminescent material for various devices. By controlling its composition and structure, scientists can tune the emission properties of nickel II sulfide, enabling its use in different applications.

For example, nickel II sulfide quantum dots have been used to create efficient and stable light-emitting diodes (LEDs) for display technology.

Interesting Quantum Properties of Nickel II Sulfide

Nickel II sulfide (NiS) is a fascinating compound that exhibits several intriguing quantum properties. These properties have attracted the attention of scientists and researchers, as they have the potential to revolutionize various fields, including electronics and materials science.

Let’s delve into some of the most interesting quantum properties of nickel II sulfide.


One of the remarkable quantum properties of nickel II sulfide is its photoconductivity. This means that it can conduct electricity more effectively when exposed to light. This property makes nickel II sulfide a promising material for applications in photodetectors and solar cells.

When light hits nickel II sulfide, it excites the electrons, allowing them to move more freely and conduct electricity. This unique property opens up possibilities for the development of more efficient and cost-effective photovoltaic devices.

Large Excitons

Nickel II sulfide also exhibits large excitons, which are bound electron-hole pairs. Excitons are crucial in various optical processes, including light absorption and emission. In nickel II sulfide, the strong electron-hole interactions give rise to large excitons, which can have a significant impact on the material’s optical properties.

Understanding and harnessing these large excitons could lead to advancements in optical devices, such as lasers and light-emitting diodes (LEDs).

Quantum Phase Transition

Another intriguing quantum property of nickel II sulfide is its ability to undergo a quantum phase transition. A quantum phase transition occurs at extremely low temperatures, where the material transitions from one phase to another due to quantum fluctuations.

In the case of nickel II sulfide, it undergoes a transition from a magnetically ordered phase to a non-magnetic phase. This property has captivated researchers, as it holds potential for the development of novel quantum devices and applications.


With its simple formula belying an intricate structure and fascinating properties, nickel II sulfide is a veritable treasure chest of quantum chemistry. From its brilliant golden luster to the mysteries of its excitonic behavior, this iconic transition metal chalcogenide continues to captivate researchers across disciplines.

Understanding the nickel II sulfide formula is just the first step to unlocking the compound’s rich quantum mechanical wonders.

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