The Basicity Characteristics of Scandium, Yttrium, and the Rare Earth Elements.

Moeller, Therald; Kremers, Howard E.

doi:10.1021/cr60116a003

Cited by 111 publications

(66 citation statements)

References 163 publications

(324 reference statements)

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“…In the system of lanthanide hydroxide bromides, Lance-Gomez and Haschke [6] showed that heavier lanthanides (Sm, Eu and Gd) produced oxide hydroxide bromide phases, whereas only hydroxide bromide phases occurred for the lighter lanthanides (La, Pr and Nd). Aside from the influence of ionic packing efficiency, the stabilization of the quaternary oxide phase in this system also was ascribed to the decreasing basicity of the lanthanide cations with atomic number [6,19]. For the same reasons (i.e., packing efficiency and cation basicity), the relative stability of oxide phases would be expected to increase as the lanthanide series is traversed in the systems examined in this work, thereby accounting for the occurrence of Eu 2 O(CO 3 ) 2 Á H 2 O in preference to EuOHCO 3 .…”

Section: Article In Pressmentioning

confidence: 96%

Hydroxide carbonates and oxide carbonate hydrate of rare earths grown on glass via a hydrothermal route

Han

Ratinac

et al. 2004

Journal of Crystal Growth

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Section: Article In Pressmentioning

confidence: 96%

Hydroxide carbonates and oxide carbonate hydrate of rare earths grown on glass via a hydrothermal route

Han

Ratinac

et al. 2004

Journal of Crystal Growth

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“…812 The drying time can be further shortened by decreasing x 1 below 2.0, but such gels did not yield transparent glasses under the sintering conditions tested in this study. The incorporation of Er 3+ ions retards gelation, because Er 3+ ions have a greater ability to generate protons by hydrolysing water than La 3+ ions, 30,31 and this hinders neutralization with imidazole.…”

Section: Discussionmentioning

confidence: 99%

Cosolvent-Free Sol–Gel Synthesis and Optical Characterization of Silica Glasses Containing LaF3 and (La,Er)F3 Nanocrystals

Suzuki¹,

Kajihara²,

Kanamura³

2014

Bulletin of the Chemical Society of Japan

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Monolithic transparent silica glasses containing LaF 3 nanocrystals were prepared by a cosolvent-free solgel method based on the pyrolysis of lanthanum trifluoroacetate. The two-step mixing of alkoxide and water, consisting of partial hydrolysis under acidic conditions and subsequent neutralization to catalyze the polycondensation of hydrophobic silica oligomers, makes it possible to shorten the processing time while eliminating the need for cosolvents. The size of the LaF 3 nanocrystals decreases with an increase in the volume fraction of LaF 3 . This suppresses Rayleigh scattering and improves transparency at LaF 3 -rich compositions. Green and red upconversion photoluminescence (PL) bands, mainly caused by energy-transfer upconversion (ETU), are observed in Er-doped samples under excitation at 980 nm. The PL intensity drastically increases with an increase in the volume fraction of the LaF 3 phase as a result of improved crystallinity of LaF 3 . The quantum yields recorded for the green and red upconversion PL bands were ca. 0.08% and ca. 0.04%, respectively.Transparent glass-ceramics containing rare-earth (RE) fluoride crystals are important for optical applications such as phosphor-based devices, scintillators, laser media, and wavelength conversion devices, because the low phonon energies of fluorides are suitable for suppressing the nonradiative decay of doped RE ions via multiphonon relaxation. 17 Silica glass is an attractive matrix for fluoride nanocrystals because of its excellent transparency in the infrared (IR) to vacuumultraviolet (UV) spectral range, good radiation hardness, chemical stability, and mechanical strength.Several research groups have reported solgel synthesis of monolithic glass-ceramics in silicametal fluoride binary systems, 813 mostly using trifluoroacetic acid (CF 3 COOH) as a fluorine source.812 These methods require alcohols as cosolvents to form homogeneous precursor solutions. In addition, the synthesis usually takes several weeks to prevent fracture during drying and sintering, and finding ways to shorten the processing time is important for the application of these materials. The fractures originate from the capillary forces that develop during the removal of liquid from the pores. They can be suppressed by increasing the pore size, which will also shorten the processing time. Recently, we reported the synthesis of monolithic silica glasses from tetraethoxysilane (TEOS) water binary systems, where macroporous gels, which can be dried and sintered relatively easily, are prepared utilizing macroscopic phase separation in parallel with gelation. 1417 Furthermore, this method does not require alcohols, which are used almost routinely as cosolvents to obtain homogeneous precursor solutions of water and alkoxides. Such reduced use of reagents is important for the synthesis of functional materials in the future.In this paper, we present a cosolvent-free solgel synthesis of monolithic silica glasses containing LaF 3 nanocrystals that utilizes the pyrolysis of RE trifluoroacetate...

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“…Samarium hydroxide dissolves in aqueous solution easier than other rare earth hydroxides at the same pH. 19) Additionally, Hong et al reported dissolution and recrystallization proceeded at pH 7 whereas did not at pH 9.…”

Section: Possible Crystal Growing Schemementioning

confidence: 99%

Changes in crystal phases and morphologies of rare earth hydroxide nitrates with ionic radius

Sato

Shiokai

Yano

et al. 2017

J. Ceram. Soc. Japan

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Rare earth hydroxide nitrates are prepared from rare earth nitrates by hydrothermal treatment. Three crystal phases, M(OH) 3 (M1), M 2 (OH) 5.14 (NO 3 ) 0.86 ·H 2 O (M2), and M 4 O(OH) 9 NO 3 (M4) are identified. The crystal phase systematically changes from M1 to M4 through M2 with decreasing radius of rare earth cation. Morphology of nanocrystal depends on the crystal phase. M1 and M4 phases grow to be nanorod, and M2 to nanoplate.

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The Basicity Characteristics of Scandium, Yttrium, and the Rare Earth Elements.

Cited by 111 publications

References 163 publications

Hydroxide carbonates and oxide carbonate hydrate of rare earths grown on glass via a hydrothermal route

Hydroxide carbonates and oxide carbonate hydrate of rare earths grown on glass via a hydrothermal route

Cosolvent-Free Sol–Gel Synthesis and Optical Characterization of Silica Glasses Containing LaF3 and (La,Er)F3 Nanocrystals

Changes in crystal phases and morphologies of rare earth hydroxide nitrates with ionic radius

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