Effect of alkali ions on the formation of rare earth fluoride by hydrothermal synthesis: structure tuning and size controlling

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

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Rare earth fluoride nano-/microcrystals: synthesis, surface modification and application

Journal of Materials Chemistry ◽

10.1039/c0jm00031k ◽

2010 ◽

Vol 20 (33) ◽

pp. 6831 ◽

Cited By ~ 565

Author(s):

Chunxia Li ◽

Jun Lin

Keyword(s):

Surface Modification ◽

Rare Earth ◽

Rare Earth Fluoride ◽

Earth Fluoride

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Thermal Decomposition of Rare Earth Fluoride Hydrates

Science ◽

10.1126/science.129.3352.842 ◽

1959 ◽

Vol 129 (3352) ◽

pp. 842-842 ◽

Cited By ~ 12

Author(s):

W. W. WENDLANDT ◽

B. LOVE

Keyword(s):

Thermal Decomposition ◽

Rare Earth ◽

Rare Earth Fluoride ◽

Earth Fluoride

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High-pressure Syntheses and Characterization of the Rare-earth Fluoride Borates RE2(BO3)F3 (RE=Tb, Dy, Ho)

Zeitschrift für Naturforschung B ◽

10.5560/znb.2013-3258 ◽

2013 ◽

Vol 68 (11) ◽

pp. 1198-1206 ◽

Cited By ~ 4

Author(s):

Ernst Hinteregger ◽

Michael Enders ◽

Almut Pitscheider ◽

Klaus Wurst ◽

Gunter Heymann ◽

...

Keyword(s):

Crystal Structure ◽

High Pressure ◽

Rare Earth ◽

Monoclinic Space Group ◽

Rare Earth Fluoride ◽

Earth Fluoride ◽

Structure Determinations ◽

New Compounds ◽

Rare Earth Fluorides

The new rare-earth fluoride borates RE2(BO3)F3 (RE=Tb, Dy, Ho) were synthesized under highpressure/ high-temperature conditions of 1:5 GPa=1200 °C for Tb2(BO3)F3 and 3:0 GPa=900 °C for Dy2(BO3)F3 and Ho2(BO3)F3 in a Walker-type multianvil apparatus from the corresponding rareearth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd2(BO3)F3. The new rare-earth fluoride borates crystallize in the monoclinic space group P21/c (Z = 8) with the lattice parameters a=16:296(3), b=6:197(2), c=8:338(2) Å , b =93:58(3)° for Tb2(BO3)F3, a= 16:225(3), b = 6:160(2), c = 8:307(2) Å , b = 93:64(3)° for Dy2(BO3)F3, and a = 16:189(3), b = 6:124(2), c = 8:282(2) Å , β= 93:69(3)° for Ho2(BO3)F3. The four crystallographically different rare-earth cations (CN=9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO3]3- groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations.

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