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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 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.
Most of the algebraic properties of the Christoffel symbols follow from their relationship to the affine connection; only a few follow from the fact that the structure group is the orthogonal group O(m, n) (or the Lorentz group O(3, 1) for general relativity). Christoffel symbols are used for performing practical calculations.
The first set of commonly used mineral symbols was published in 1983 and covered the common rock-forming minerals using 192 two- or three-lettered symbols. [1] These type of symbols are referred to as Kretz symbols. More extensive lists were subsequently made available in the form of publications [2] [3] or posted on journal webpages. [4]
3. Between two groups, may mean that the first one is a proper subgroup of the second one. > (greater-than sign) 1. Strict inequality between two numbers; means and is read as "greater than". 2. Commonly used for denoting any strict order. 3. Between two groups, may mean that the second one is a proper subgroup of the first one. ≤ 1.
Symbol Name Meaning SI unit of measure nabla dot : the divergence operator often pronounced "del dot" per meter (m −1) : nabla cross : the curl operator often pronounced "del cross"
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.
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