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The lanthanides become harder as the series is traversed: as expected, lanthanum is a soft metal. Lanthanum has a relatively high resistivity of 615 nΩm at room temperature; in comparison, the value for the good conductor aluminium is only 26.50 nΩm. [28] [29] Lanthanum is the least volatile of the lanthanides. [30]
Lanthanide metals react exothermically with hydrogen to form LnH 2, dihydrides. [1] With the exception of Eu and Yb, which resemble the Ba and Ca hydrides (non-conducting, transparent salt-like compounds),they form black pyrophoric, conducting compounds [6] where the metal sub-lattice is face centred cubic and the H atoms occupy tetrahedral sites. [1]
The lanthanite crystal structure consists of layers of 10-fold coordinated REE-oxygen (O) polyhedra and carbonate (CO 3 2−) groups connected by hydrogen bonds to interlayer water molecules, forming a highly hydrated structure.
Lanthanide chlorides are a group of chemical compounds that can form between a lanthanide element (from lanthanum to lutetium) and chlorine. The lanthanides in these compounds are usually in the +2 and +3 oxidation states , although compounds with lanthanides in lower oxidation states exist.
Organolanthanide chemistry is the field of chemistry that studies organolanthanides, compounds with a lanthanide-carbon bond. Organolanthanide compounds are different from their organotransition metal analogues in the following ways: They are far more air- and water-sensitive and are often pyrophoric.
Lanthanide oxides: clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium. The chemistry of the lanthanides is dominated by the +3 oxidation state, and in Ln III compounds the 6s electrons and (usually) one 4f electron are lost and the ions have the configuration [Xe]4f (n−1). [23]
Lanthanum chloride is also used in biochemical research to block the activity of divalent cation channels, mainly calcium channels.Doped with cerium, it is used as a scintillator material.
Praseodymium(IV) oxide can be produced by boiling Pr 6 O 11 in water or acetic acid: [16] Pr 6 O 11 + 3 H 2 O → 4 PrO 2 + 2 Pr(OH) 3. Praseodymium(III,IV) oxide is the most stable form of the praseodymium oxides at ambient temperature and pressure. [17] It is soluble in water [18] and has a cubic fluorite structure. [19]