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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]
Lanthanum oxide is a white solid that is insoluble in water, but dissolves in acidic solutions. La 2 O 3 absorbs moisture from air, converting to lanthanum hydroxide. [2] Lanthanum oxide has p-type semiconducting properties and a band gap of approximately 5.8 eV. [3]
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.
It is a white solid that is highly soluble in water and alcohols. Preparation. Anhydrous lanthanum(III) chloride can be produced by the ammonium chloride route.
Lanthanum hydroxide does not react much with alkaline substances, however is slightly soluble in acidic solution. [2] In temperatures above 330 °C it decomposes into lanthanum oxide hydroxide (LaOOH), which upon further heating decomposes into lanthanum oxide (La 2 O 3): [4]
Lanthanide and actinide aqua ions have higher solvation numbers (often 8 to 9), with the highest known being 11 for Ac 3+. The strength of the bonds between the metal ion and water molecules in the primary solvation shell increases with the electrical charge, z, on the metal ion and decreases as its ionic radius, r, increases. Aqua ions are ...
The lanthanides that dissolved as a result of the acid treatment were subjected to solvent extraction, to capture the europium, and purify the other individual components of the ore. A further product included a lanthanide mix, depleted of much of the cerium, and essentially all of samarium and heavier lanthanides.