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The lanthanide contraction is the greater-than-expected decrease in atomic radii and ionic radii of the elements in the lanthanide series, from left to right. It is caused by the poor shielding effect of nuclear charge by the 4f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right.
All of the lanthanides form Ln 2 Q 3 (Q= S, Se, Te). [18] The sesquisulfides can be produced by reaction of the elements or (with the exception of Eu 2 S 3) sulfidizing the oxide (Ln 2 O 3) with H 2 S. [18] The sesquisulfides, Ln 2 S 3 generally lose sulfur when heated and can form a range of compositions between Ln 2 S 3 and Ln 3 S 4.
The LN-3 inertial navigation system is an inertial navigation system (INS) that was developed in the 1960s by Litton Industries. It equipped the Lockheed F-104 Starfighter versions used as strike aircraft in European forces.
The principal sources of rare-earth elements are the minerals bastnäsite (RCO 3 F, where R is a mixture of rare-earth elements), monazite (XPO 4, where X is a mixture of rare-earth elements and sometimes thorium), and loparite ((Ce,Na,Ca)(Ti,Nb)O 3), and the lateritic ion-adsorption clays.
A metal ion in aqueous solution or aqua ion is a cation, dissolved in water, of chemical formula [M(H 2 O) n] z+.The solvation number, n, determined by a variety of experimental methods is 4 for Li + and Be 2+ and 6 for most elements in periods 3 and 4 of the periodic table.
In 1953, Brillouin derived a general equation [10] stating that the changing of an information bit value requires at least kT ln(2) energy. This is the same energy as the work Leo Szilard 's engine produces in the idealistic case, which in turn equals the same quantity found by Landauer .
For the thermodynamic operation of adding two systems with internal energies U 1 and U 2, to produce a new system with internal energy U, one may write U = U 1 + U 2; the reference states for U, U 1 and U 2 should be specified accordingly, maintaining also that the internal energy of a system be proportional to its mass, so that the internal ...
The ionization energy will be the energy of photons hν i (h is the Planck constant) that caused a steep rise in the current: E i = hν i. When high-velocity electrons are used to ionize the atoms, they are produced by an electron gun inside a similar evacuated tube. The energy of the electron beam can be controlled by the acceleration voltages.