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α-Calcium nitride adopts an anti-bixbyite structure, similar to Mn 2 O 3, except that the positions of the ions are reversed: calcium (Ca 2+) take the oxide (O 2−) positions and nitride ions (N 3−) the manganese (Mn 3+). In this structure, Ca 2+ occupies tetrahedral sites, and the nitride centres occupy two different types of octahedral ...
The allowed size of the cation for a given structure is determined by the critical radius ratio. [2] If the cation is too small, then it will attract the anions into each other and they will collide hence the compound will be unstable due to anion-anion repulsion; this occurs when the radius ratio drops below the critical radius ratio for that ...
Ionic radius, r ion, is the radius of a monatomic ion in an ionic crystal structure. Although neither atoms nor ions have sharp boundaries, they are treated as if they were hard spheres with radii such that the sum of ionic radii of the cation and anion gives the distance between the ions in a crystal lattice.
However, if chloride ingress occurs in service (from sea water or de-icing salt), the AFm undergoes ion exchange, gaining chloride and forming Friedel's salt (Cl-AFm), while releasing soluble nitrite ions to the pore fluid. As a result, the aqueous ratio of [NO 2 −]/[Cl −] increases which assures corrosion inhibition of embedded steel. [6]
For typical ionic solids, the cations are smaller than the anions, and each cation is surrounded by coordinated anions which form a polyhedron.The sum of the ionic radii determines the cation-anion distance, while the cation-anion radius ratio + / (or /) determines the coordination number (C.N.) of the cation, as well as the shape of the coordinated polyhedron of anions.
Sodium nitride and potassium nitride has been generated, but remains a laboratory curiosity. The nitrides of the alkaline earth metals that have the formula M 3 N 2 are however numerous. Examples include beryllium nitride (Be 3 N 2), magnesium nitride (Mg 3 N 2), calcium nitride (Ca 3 N 2), and strontium nitride (Sr 3 N 2). The nitrides of ...
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
In chemistry, ion association is a chemical reaction whereby ions of opposite electric charge come together in solution to form a distinct chemical entity. [1] [2] Ion associates are classified, according to the number of ions that associate with each other, as ion pairs, ion triplets, etc. Ion pairs are also classified according to the nature of the interaction as contact, solvent-shared or ...