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Sodium fluoride is an inorganic ionic compound, dissolving in water to give separated Na + and F − ions. Like sodium chloride , it crystallizes in a cubic motif where both Na + and F − occupy octahedral coordination sites ; [ 33 ] [ 34 ] its lattice spacing, approximately 462 pm , is smaller than that of sodium chloride (564 pm).
Sodium fluoride: yellow is fluorine, purple is sodium. They are isoelectronic, but fluorine is bigger because its nuclear charge is lower. The alkali metals form monofluorides. All are soluble and have the sodium chloride (rock salt) structure, [47] Because the fluoride anion is basic, many alkali metal fluorides form bifluorides with the ...
Typically the fluoride anion is surrounded by four or six cations, as is typical for other halides. Sodium fluoride and sodium chloride adopt the same structure. For compounds containing more than one fluoride per cation, the structures often deviate from those of the chlorides, as illustrated by the main fluoride mineral fluorite (CaF 2 ...
The chemical identity of the ions added is also important in many uses. For example, fluoride containing compounds are dissolved to supply fluoride ions for water fluoridation. [88] Solid salts have long been used as paint pigments, and are resistant to organic solvents, but are sensitive to acidity or basicity. [89]
In such a lattice, it is usually not possible to distinguish discrete molecular units, so that the compounds formed are not molecular. However, the ions themselves can be complex and form molecular ions like the acetate anion or the ammonium cation. Representation of ionic bonding between lithium and fluorine to form lithium fluoride.
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.
Solubility of salts in organic solvents is a function of both the cation and the anion. The solubility of cations in organic solvents can be enhanced when the anion is lipophilic. Similarly, the solubility of anions in organic solvents is enhanced with lipophilic cations. The most common lipophilic cations are quaternary ammonium cations ...
In inorganic chemistry, Fajans' rules, formulated by Kazimierz Fajans in 1923, [1] [2] [3] are used to predict whether a chemical bond will be covalent or ionic, and depend on the charge on the cation and the relative sizes of the cation and anion. They can be summarized in the following table: