Search results
Results from the WOW.Com Content Network
Lanthanide ions have notable luminescent properties due to their unique 4f orbitals. Laporte forbidden f-f transitions can be activated by excitation of a bound "antenna" ligand. This leads to sharp emission bands throughout the visible, NIR, and IR and relatively long luminescence lifetimes. [85]
Lanthanides can be used because their small size (ionic radius) gives them the ability to replace metal ions inside protein complex such as calcium or nickel. The optical properties of lanthanide ions such as Ln(III) originate in the special features of their electronic [Xe]4f n configurations. [ 4 ]
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]
ion is similar in size to the Ca 2+ ion, it is sometimes used as an easily traced substitute for the latter in medical studies. [80] Lanthanum, like the other lanthanides, is known to affect human metabolism, lowering cholesterol levels, blood pressure, appetite, and risk of blood coagulation.
The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), [1] are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals.
Other considerations about the host lattice include choice of cation and anions. Importantly, cations should have similar radii to the intended dopant ions: For example, when using lanthanide dopant ions, certain alkaline-earth (Ca 2+), rare-earth (Y +), and transition-metal ions (Zr 4+) all fulfill this requirement, as well as Na +. Similarly ...
The most common lanthanide ions used in photon upconversion are the pairs erbium-ytterbium (Er 3+,Yb 3+) or thulium-ytterbium (Tm 3+, Yb 3+). In such combinations ytterbium ions are added as antennas, to absorb light at around 980 nm and transfer it to the upconverter ion. If this ion is erbium, then a characteristic green and red emission is ...
Samarium dissolves readily in dilute sulfuric acid to form solutions containing the yellow [22] to pale green Sm(III) ions, which exist as [Sm(OH 2) 9] 3+ complexes: [21] 2Sm (s) + 3H 2 SO 4 (aq) → 2Sm 3+ (aq) + 3SO 2− 4 (aq) + 3H 2 (g) Samarium is one of the few lanthanides with a relatively accessible +2 oxidation state, alongside Eu and ...