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The Hydrosphere and Water Chemistry
Published in Stanley E. Manahan, Environmental Chemistry, 2022
The coordination number of a metal atom, or ion, is the number of ligand electron-donor groups that are bonded to it. The most common coordination numbers are 2, 4, and 6. Polynuclear complexes contain two or more metal atoms joined together through bridging ligands, frequently OH, as shown for iron(III) in Reaction 2.43.
Introduction
Published in Yip-Wah Chung, Monica Kapoor, Introduction to Materials Science and Engineering, 2022
An example is aluminum. This unit cell has eight atoms at the cube corners and six atoms at the cube faces. Since each atom at the cube face is shared by two cubes, the fcc unit cell contains four atoms. The coordination number is 12. Again, assuming close packing with the nearest neighbors (the close packing is along the face diagonal) and spherical atoms, we can show that a2=4R. The PF can be shown to be equal to π26 or about 74%. Therefore, the fcc structure is more tightly packed than bcc.
Chemical Equilibrium
Published in Armen S. Casparian, Gergely Sirokman, Ann O. Omollo, Rapid Review of Chemistry for the Life Sciences and Engineering, 2021
Armen S. Casparian, Gergely Sirokman, Ann O. Omollo
The region surrounding the central atom or ion and its ligands is called the coordination sphere. The coordination number is the total number of points at which the central atom or ion attaches to its ligands. Both [Co(NH3)6]3+ and [CoCl(NH3)5]2+ have coordination numbers of 6. The most common coordination numbers observed in complex ions are 2, 4, and 6. If the complex carries a net electric charge, as the two examples given here do, it is called a complex ion. If it is electrically neutral, it is referred to as a coordination compound. An example of a coordination compound is [Co(NH3)6]Cl3.
DEM simulation of dumbbell shaped particles under vertical vibration
Published in Particulate Science and Technology, 2023
Coordination number is defined as the average number of particles in contact with a single particle. For a vibrated bed, time-averaged coordination number of particles is determined using Equation (9). and are the number of particles in contact and total number of particles at t, respectively. Here, stands for the time average of the mean coordination number. As the aspect ratio of particle increases, its surface area increases, and hence the available area for other particles to make contact increases. The same is reported in Figure 11, where with the increase in available surface area coordination number increases for all input energies.
Bis(cyclopentadienyl) lanthanide benzylthiolate: synthesis, molecular structure and catalytic property for ε-caprolactone –polymerization
Published in Journal of Sulfur Chemistry, 2019
Fugen Yuan, Manman Zhang, Li Li, Jiayue Lu
Complex 2 is a dimer. Two Yb atoms were bridged by two S atoms without any solvent molecules. Each Yb atom was coordinated by two cyclopentadienyl groups and two sulfur atoms. The coordination number is 8. Two centriods of cyclopentadienyl groups and two S atoms construct a distorted tetrahedron around a Yb atom.