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An atomic or molecular system with an excess of negative charge. Negative ions, also called anions, are formed in attachment processes in which an additional electron is captured by an atom or molecule. Negative ions were first reported in the early days of mass spectrometry. It was soon learned that even a small concentration of such weakly bound, negatively charged systems had an appreciable effect on the electrical conductivity of gaseous discharges. Negative ions now play a major role in a number of areas of physics and chemistry involving weakly ionized gases and plasmas. Applications include accelerator technology, injection heating of thermonuclear plasmas, material processing, and the development of tailor-made gaseous dielectrics. In nature, negative ions are known to be present in tenuous plasmas such as those found in astrophysical and aeronomical environments. The absorption of radiation by negative hydrogen ions in the solar photosphere, for example, determines the Sun's spectral distribution. See Ion sources
negative ion[′neg·əd·iv ′ī‚än]
ion(1) (IDL On the Net) See IDL.
(2) (ION) An NVIDIA graphics platform typically used in Atom-based netbooks. See Intel Atom.
(3) An ion is an atom with fewer or greater electrons than normal as a result of radiation or chemical reaction. A positive ion, called a "cation" (pronounced "cat-eye-en"), has one or more electrons stripped out, which means it has fewer electrons in its electron shells than it has protons in its nucleus. A negative ion, called an "anion" (pronounced "an-eye-en"), is an atom that has one or more electrons forcibly added.
Cations, Anions, Cathodes and Anodes
Although one might think cations are in cathodes and anions are in anodes, the opposite is true. When the terms were coined, the concept was that positive cations were attracted to the negative cathode, and negative anions were attracted to the positive anode.
Batteries Contain Positive and Negative Ions
In a battery, there are positive ions on one side and negative ions on the other. When a conductor is placed in between to complete the circuit, the electrons flow from the negative ions to the positive side where they join the positive ions. See ion deposition.