Gd₂O(CO₃)₂ · H₂O Particles and the Corresponding Gd₂O₃: Synthesis and Applications of Magnetic Resonance Contrast Agents and Template Particles for Hollow Spheres and Hybrid Composites

Abstract

The solution approach was employed to yield multifunctional amorphous Gd2O(CO3)2 · H2O colloidal spheres by reflux of an aqueous solution containing GdCl3 · 6H2O and urea. By elongating the reaction time, crystalline rhombus‐ shaped Gd2O(CO3)2 · H2O with at least 87% yield could be formed and were also accompanied by some rectangular particles. High‐resolution synchrotron powder X‐ray diffraction provides crystal structure information, such as cell dimensions, and indexes the exact crystal packing with hexagonal symmetry, which is absent from the Joint Committee on Powder Diffraction Standards file, for the crystalline rhombus sample. Particle formation was studied based on the reaction time and the concentration ratio of [urea]/[GdCl3 · 6H2O]. After a calcination process, the amorphous spheres and crystalline rhombus Gd2O(CO3)2 · H2O particles convert into crystalline Gd2O3 at temperatures above 600 °C. For in vitro magnetic resonance imaging (MRI), both Gd2O(CO3)2 · H2O and Gd2O3 species show the promising T1‐ and T2‐weighted effects and could potentially serve as bimodal T1‐positive and T2‐negative contrast agents. The amorphous Gd2O(CO3)2 · H2O contrast agent further demonstrates enhanced contrast of the liver and kidney using a dynamic contrast‐enhanced MR imaging (DCE‐MRI) technique for in vivo investigation. The multifunctional capability of the amorphous Gd2O(CO3)2 · H2O spheres was also evidenced by the formation of nanoshells using these amorphous spheres as the template. Surface engineering of the amorphous Gd2O(CO3)2 · H2O spheres could be performed by covalent bonding to form hollow silica nanoshells and hollow silica@Fe3O4 hybrid particles.

Nanoscale Gd2O2S:Tb Scintillators for High-Resolution Fluorescent Imaging of Cold Neutrons

“…Figure2apresents the X-ray diffraction (XRD) patterns of the as-synthesized Gd 2 O(CO 3 ) 2 •H 2 O:Tb 3+ precursor. The particles' apparent peaks indicate an amorphous structure, which is in good agreement with the reports in the literature 38. Fourier transform infrared spectroscopy (FTIR) of the precursor (Figure2b) shows a broad absorption band in the ∼3000−3750 cm −1 spectral region, which is overlapped by the O−H stretching in molecular H 2 O.…”

Up-conversion luminescence and near-infrared quantum cutting in Y6O5F8:RE3+ (RE = Yb, Er, and Ho) with controllable morphologies by hydrothermal synthesis

“…2b exhibits the typical O-H stretching (3650 and 3400 cm −1 ) and Y-O bond (513 cm −1 ), but the O-H stretching has almost disappeared after annealing due to the phase transition (Fig. 2c), leaving only the strong absorption peaks ascribed to the Y-O bond (532 and 450 cm −1 ), 23,24 and this result is in agreement with the phase analysis of the XRD in Fig. 1.…”

“…, and δ-CO 3 2− , respectively. 22,23 This observation reveals the presence of the hydroxyl and carbonate groups, which agrees with the chemical formula of Y(OH)CO 3 identified from the XRD pattern. The hydrothermal product formed using CTAB as the additive is a white powder, and crystallized into the Y(OH) 1.63 F 1.37 phase perfectly (agreeing with the JCPD Standard card no.…”

Microwave‐Assisted Seeded Growth of Lanthanide‐Based Nanoparticles for Imaging and Therapy

“…Similar XRD patterns have been reported for amorphous spherical gadolinium and dysprosium carbonate particles 9a. 15 After calcination of the sample at 800 °C for 1 h, the XRD spectrum displayed sharp reflections typical for Ho 2 O 3 .…”