Related Experiment Video
Updated: Jun 18, 2026
08:40
Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules
Published on: April 28, 2014
"Amorphous nickel sulfide" is hydrated nanocrystalline nis with a core-shell structure
Shanshan Huang1, Kenneth D M Harris, Elisa Lopez-Capel
1School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3YE, Wales.
Inorganic Chemistry
|November 19, 2009
Summary
Amorphous nickel sulfide is a hydrated nanoparticulate material, not truly amorphous. It features a crystalline core and hydrated shell, with structure varying by preparation pH.
Area of Science:
- Materials Science
- Inorganic Chemistry
- Nanotechnology
Background:
- Nickel sulfide (NiS) is often prepared as an "amorphous" material from aqueous solutions.
- Understanding the true structure of precipitated materials is crucial for their applications.
Purpose of the Study:
- To characterize the structure of "amorphous nickel sulfide" prepared under various conditions.
- To investigate the influence of pH on the phase evolution of nickel sulfide.
Main Methods:
- Experimental techniques including X-ray diffraction and electron microscopy were employed.
- Synthesis of nickel sulfide was performed under controlled aqueous conditions at different pH levels.
Main Results:
- "Amorphous nickel sulfide" is a hydrated nanoparticulate material (NiS·1.5H2O) with a crystalline millerite (NiS) core and hydrated shell.
- Acidic conditions (pH 3, 5) lead to transformation into polydymite (Ni3S4) and heazlewoodite (Ni3S2) over time.
- Neutral to alkaline conditions (pH 7, 9) prevent this transformation, while pH 12 yields metastable NiAs-type NiS.
Conclusions:
- The structure of nickel sulfide precipitates is highly dependent on preparation pH.
- The term "amorphous nickel sulfide" is a misnomer; the material is nanoparticulate and hydrated.
- Controlled synthesis conditions are necessary to obtain desired nickel sulfide phases.
Related Concept Videos
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
01:03Precipitation Gravimetry
Precipitation gravimetry is based on converting an analyte into a sparingly soluble precipitate, which is separated by filtration and weighed. An ideal precipitate should be pure, insoluble, of known composition, and easily filtered from the reaction mixture.
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
02:37Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
02:34Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...