Europium Luminescence as a Structural Probe: Structure‐Dependent Changes in Eu³⁺‐Substituted Th(C₂O₄)₂·xH₂O (x = 6, 2, and 0)

Abstract

Three different phases of thorium(IV) oxalate hydrate [Th(C 2 O 4 ) 2 ·xH 2 O] with different water contents, namely, the hexahydrate, dihydrate, and anhydrous phases, were prepared by thermal treatment of the as-precipitated hydrated thorium(IV) oxalates. With the change in water content, the structure changes from monoclinic (C2/m) for the hexahydrate to monoclinic (C2/c) for the dihydrate and finally to a highly disordered phase for the anhydrous state. The local coordination around the Th 4+ ions in these structures was monitored by using Eu 3+ ions as luminescent probes. The analyses of the emission spectra owing to the electric-dipole transitions (EDTs) and magnetic-dipole transitions (MDTs) of the Eu 3+ ions in the different phases revealed that the site symmetry around the Th 4+ ions decreases systematically

Crystal structure of a mixed-ligand terbium(III) coordination polymer containing oxalate and formate ligands, having a three-dimensional fcu topology

“…complexes containing oxygen donor ligands (Cheng et al, 2007;Zhu et al, 2007). All of the bond lengths and bond angles in the formate and oxalate anions are also within normal ranges (Rossin et al, 2012;Hong et al, 2014;Gupta et al, 2015). The coordination modes of the formate and oxalate ligands in (I) ( Fig.…”

“…Among the ligands in this class, for instance, terephthalic acid is known to provide an efficient energy transfer to support strong lanthanide(III)-centered luminescent emission via the 'antenna effect' (Samuel et al, 2009). On the other hand, small rigid planar species with versatile coordination oxygen donor sites such as oxalate, carbonate, nitrate, and formate anions are also a very important class of ligands for the preparation of lanthanide coordination polymers (Hong et al, 2014;Gupta et al, 2015). These small versatile ligands can bind to metals in different modes, resulting in the formation of multi-dimensional coordination networks with short intermetallic distances, which can aid the energy-transfer process between chromophoric antenna ligands and lanthanide(III) ions (Wang et al, 2012).…”

Probing crystal structure and site‐selective photo‐physical properties of various Eu3+‐doped niobates

“…In an asymmetric environment, the intensity of the EDT will be higher than the MDT and in a symmetric environment, the reverse is the case. Thus apart from orange–red emission, which has application in phosphor material, its sensitivity to local site in the host matrix is extensively used as local structure probe . PL study was performed on 2 at.…”

“…Thus apart from orange-red emission, which has application in phosphor material, its sensitivity to local site in the host matrix is extensively used as local structure probe. 6,30,31 PL study was performed on 2 at. % Eu 3+ -doped compounds in order to probe the local site symmetry around the La atom and exploring their phosphor characteristics.…”

Light‐induced electrons suppressed by Eu3+ ions doped in Ca11.94−xSrxAl14O33 caged phosphors for LED and FEDs

“…However, in the case of the unstable trivalent rare earth ions such as Eu 3+ ion, it is still a challenge to understand how Sr doping affects the formation of encaged electrons and modulates the luminescence of unstable rare-earth ions. On the other hand, not only Eu 3+ ions are used as a luminescent probe in many fields, including structural probe, detection of medicine and physiological range, [19][20][21][22][23][24] but also Eu 3+ and Eu 2+ are good emission centers in phosphors for white LEDs and displays. [25][26][27][28][29][30][31] 0.06 .…”