13709-49-4Relevant articles and documents
Gettmann, W.,Greis, O.
, p. 255 - 264 (1978)
An organically templated yttrium fluoride with a 'Super-Diamond' structure
Stephens, Nicholas F.,Lightfoot, Philip
, p. 260 - 264 (2007)
An organically templated yttrium fluoride has been prepared hydrothermally and characterised by X-ray powder diffraction. The crystal structure of [C3N2H12]0.5[Y3F10] may be regarded as a 'Super-Diamond' framework, space group Fdover(3, -) m, a=15.4817(1) A, where each carbon atom site of the diamond structure is replaced by a polyhedral [Y6F8F24/2]2- unit. The basic framework type is isostructural with the known phase (H3O)[Yb3F10]·H2O. The novelty in the present case lies in the use of the organic structure-directing agent 1,3-diaminopropane.
Phase equilibria in the system sodium fluoride-yttrium fluoride
Thoma,Hebert,Insley,Weaver
, p. 1005 - 1012 (1963)
A phase diagram of the condensed system NaF-YF3 was constructed from data obtained in cooling-curve and quenching experiments. The number and identity of phases co-existing at equilibrium were determined by use of the X-ray diffractometer and the petrographic microscope. Two compounds, NaF-YF3 and 5NaF-9YF3, were formed from the components. Each compound exists in two polymorphic forms, the high-temperature form in both cases crystallizing from molten mixtures as fluorite-like cubic crystals. The two cubic phases form a continuous solid solution with a maximum melting temperature of 975° at the composition 5NaF-9YF3. Lattice parameters and refractive indices of the solid solution appear to be linear functions of the YF3 content, a = 5.447-5.530 A?., refractive index 1.430-1.470. Pure crystals of NaF·YF3 invert from the fluorite cubic form, on cooling below 691°, to a hexagonal form which is isostructural with β2-Na2ThF6, with lattice constants a = 5.95, c = 3.52 A?. The five primary phase fields below the liquidus were found to be NaF, hexagonal NaF·YF3, NaF·YF3-5NaF·9YF3 ss, and two forms of YF3. Two eutectics occur in association with these primary phases, at 29 and 75 mole% YF3 and at 638 and 947°, respectively. Because of the isomorphism of YF3 with the trifluorides of the rare earths samarium-lutetium and the similarity of their cation sizes, the system NaF-YF3 is predicted to be an approximate model for each of the binary systems SmF3-LuF3 with NaF.
The Copper Ampoule: A New Reactor for the Solid-State Synthesis of Complex Lanthanide Fluorides
Egger, Philipp,Peters, Nils,Hulliger, Juerg
, p. 152 - 155 (1999)
For the first time, copper ampoules have been used as reactors for the solid-state synthesis of complex lanthanide fluorides under vacuum. The high ductility of copper allows for high-vacuum tight sealing of the ampoules by cold welding. Furthermore, no chemical reactivity of copper toward solid fluorides has been observed. Thus, for an examination in view of optical upconversion properties, the superstructure phases Ba4-xY3+xF17+x(x≈0.08) and Pb4?xY3±xF17±x(x≤0.2) have been synthesized by annealing of mixtures of binary fluorides in evacuated copper ampoules.
Hydrothermal synthesis and white luminescence of Dy3+-Doped NaYF4 microcrystals
Cao, Chunyan,Yang, Hyun Kyoung,Chung, Jong Won,Moon, Byung Kee,Choi, Byung Chun,Jeong, Jung Hyun,Kim, Kwang Ho
, p. 3405 - 3411 (2011)
2 mol% Dy3+-doped NaYF4 microcrystals with different morphologies and crystalline phases have been synthesized through a hydrothermal method without assistance of any surfactant, catalyst, or template by controlling reaction temperatures, reaction time, and molar ratios of reactants. For comparison, the samples were also synthesized by a direct coprecipitation method. The final products were characterized by X-ray diffraction, field emission scanning electron microscopy, photoluminescence excitation and emission spectra, and luminescent dynamic decay curves. Dy3+ exhibits bright white light under near ultraviolet 350 or 351 nm excitation and the white light was evaluated by chromaticity coordinates. The experimental results suggest that the obtained Dy3+-doped NaYF4 microcrystals have potential applications in white light materials.
Studies on the reaction of ammonium fluoride with lithium carbonate and yttrium oxide
Kowalczyk, Ewa,Diduszko, Ryszard,Kowalczyk, Zbigniew,Leszczynski, Tomasz
, p. 189 - 196 (1995)
The reaction of Y2O3 and Li2CO3 with NH4F to produce LiYF4 was studied by thermogravimetric and X-ray diffraction methods. NH4F reacts easily with Li2CO3 in a one-step exothermic process. Fluorination of yttrium oxide gives first YF3 . 1.5NH3 which decomposes at 300-380°C to YF3 +NH3. This process is exothermic. In the absence of excess NH4F, an amou nt of YOF is produced, in addition to YF3, as a product of the reaction of YF3 and unreacted Y2O3. This reaction is endothermic. In the ternary system NH4F-Li2CO3-Y2O3, the first reacts separately with each of the other two and the resulting mixture of simple yttrium and lithium fluorides is converted into LiYF4 at high temperatures.
Polyol-mediated syntheses and characterizations of NaYF4, NH4Y3F10 and YF3 nanocrystals/sub-microcrystals
Qin, Ruifei,Song, Hongwei,Pan, Guohui,Hu, Lanying,Yu, Hongquan,Li, Suwen,Bai, Xue,Fan, Libo,Dai, Qilin,Ren, Xinguang,Zhao, Haifeng,Wang, Tie
, p. 2130 - 2136 (2008)
In this paper, NaYF4 nanocrystals and NH4Y3F10 sub-microcrystals were prepared using a polyol method. After being annealed, NH4Y3F10 can convert into YF3, which is a very efficient host matrix for upconversion. The structures of obtained NaYF4, NH4Y3F10 and YF3 samples are pure cubic phase, a mixture of cubic and hexagonal phase and pure orthorhombic phase, respectively. The size of obtained NaYF4 nanocrystals is about 20 nm, and those of NH4Y3F10 and YF3 sub-microcrystals are both about 200 nm. When co-doped with Er3+ and Yb3+, NaYF4 and YF3 samples can emit bright light under 978 nm excitation. Upconversion mechanisms in Yb3+/Er3+ co-doped NaYF4 and YF3 samples were discussed.
Synthesis and characterization of mixed fluoride Y1-xSr2+1.5xF7 (-1.0 < x < 0.5)
Patwe,Achary,Tyagi,Moorthy
, p. 761 - 769 (1999)
A series of mixed fluorides with the general formula Y1-xSr2+1.5xF7 (x = -1.0 0.5Sr2.75F7 shows a cubic symmetry (fluorite-type structure) with a = 5.776 angstrom. On decreasing the Sr2+ content or increasing the Y3+ content in Y1-xSr2+1.5xF7, a phase with tetragonal symmetry with a = 11.416 angstrom and c = 13.291 angstrom was observed in the composition YSr2F7, whereas in the composition Y2Sr0.5F7, a phase with hexagonal symmetry with a = 6.882 angstrom and c = 7.032 angstrom was observed. The existence of phases such as YSr2F7 and Y2Sr0.5F7 was confirmed. We observed a coexistence of rhombohedral and hexagonal phases beyond a particular nominal composition in this series of compounds.
Jianming, Xu,Changzhen, Wang,Zhitong, Sui
, p. L5 - L8 (1992)
Ionic conductivity in solid solutions of PbF2 and YF3
Patwe,Balaya,Goyal,Tyagi
, p. 1743 - 1749 (2001)
Ionic conductivity of a series of fluorite-type solid solutions Pb1-xYxF2+x (0.007 ≤ x ≤ 0.222) has been measured in the frequency range 100 Hz - 3 MHz and in the temperature range 25-250°C under vacuum. The conductivity decreases and the activation energy increases gradually upon increasing the yttrium content up to ～ 4.5 mol% of Y3+ whereas, beyond that and up to 22 mol% of Y3+, the ionic conductivity increases and the activation energy decreases. Thus two distinct regions in the general composition Pb1-xYxF2+x could be delineated, in one the polarizability factor predominates over the number of extra-interstitial F anions and vice-versa in the other region. These results indicate the competing effects between the disorder caused by interstitial F anions and the polarizability of the host and guest cations.
Lanthanide doped Y6O5F8/YF3 microcrystals: Phase-tunable synthesis and bright white upconversion photoluminescence properties
Wang, Song,Deng, Ruiping,Guo, Hailing,Song, Shuyan,Cao, Feng,Li, Xiyan,Su, Shengqun,Zhang, Hongjie
, p. 9153 - 9158 (2011/01/11)
High-quality Y6O5F8/YF3 microcrystals have been synthesised by using a hydrothermal and subsequent calcination route. Upon changing the initial solution pH value, the as-prepared microcrystal can be well tuned from YF3 octahedron microcrystals to YF3 hollow spheres and finally to Y6O5F 8 microtubes. The as-obtained microcrystals have been characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence (PL) spectra. When the Y6O 5F8:Ln3+ microtubes are excited by a 980 nm continual wave laser diode, bright red, green, and blue room temperature upconversion PL emissions have been observed. A series of white light emissions have been obtained by precisely adjusting dopants concentration in Y 6O5F8 microtubes. The Royal Society of Chemistry 2010.
