![]() ![]() Formation Halite, the mineral form of sodium chloride, forms when salty water evaporates leaving the ions behind. Born predicted crystal energies based on the assumption of ionic constituents, which showed good correspondence to thermochemical measurements, further supporting the assumption. ![]() Principal contributors to the development of a theoretical treatment of ionic crystal structures were Max Born, Fritz Haber, Alfred Landé, Erwin Madelung, Paul Peter Ewald, and Kazimierz Fajans. These compounds were soon described as being constituted of ions rather than neutral atoms, but proof of this hypothesis was not found until the mid-1920s, when X-ray reflection experiments (which detect the density of electrons), were performed. Many other inorganic compounds were also found to have similar structural features. This revealed that there were six equidistant nearest-neighbours for each atom, demonstrating that the constituents were not arranged in molecules or finite aggregates, but instead as a network with long-range crystalline order. In 1913 the structure of sodium chloride was determined by William Henry Bragg and William Lawrence Bragg. History of discovery X-ray spectrometer developed by W. In terms of their properties, such species often are more similar to organic compounds. Some salts have large cations, large anions, or both. As solids they are almost always electrically insulating, but when melted or dissolved they become highly conductive, because the ions become mobile. Salts composed of small ions typically have high melting and boiling points, and are hard and brittle. Salts usually form crystalline structures when solid. Individual ions within a salt usually have multiple nearest neighbours, so are not considered to be part of molecules, but instead part of a continuous three-dimensional network. Salt containing basic ions hydroxide (OH −) or oxide (O 2−) are classified as bases, for example sodium hydroxide. Each ion can be either monatomic (termed simple ion), such as fluoride (F −), and sodium (Na +) and chloride (Cl −) in sodium chloride, or polyatomic, such as sulfate ( SO 2−ģ) ions in ammonium carbonate. The component ions in a salt can be either inorganic, such as chloride (Cl −), or organic, such as acetate ( CH The constituent ions are held together by electrostatic forces termed ionic bonds. In chemistry, a salt or ionic compound is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a neutral compound with no net electric charge. The yellow stipples show the electrostatic forces. The purple spheres represent sodium cations, Na +, and the green spheres represent chloride anions, Cl −. The crystal structure of sodium chloride, NaCl, a typical ionic compound. Not to be confused with Salt or Sodium chloride. ![]()
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