Characterization and Luminescence of Eu3+- and Gd3+-Doped Hydroxyapatite Ca10(PO4)6(OH)2

Luminescence properties of europium-doped Ca10-xEux(PO4)6(OH)2 (xEu = 0, 0.01, 0.02, 0.10 and 0.20) and gadolinium-doped hydroxyapatite Ca9.80Gd0.20(PO4)6(OH)2 (HA), synthesized via solid-state reaction at T = 1300 °C, were investigated using scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), and luminescence spectroscopy. Crystal structure characterization (from unit cell parameters determination to refined atomic positions) was achieved in the P63/m space group. FTIR analyses show only slight band shifts of (PO4) modes as a function of the rare earth concentration. Structural refinement, achieved via the Rietveld method, and luminescence spectroscopy highlighted the presence of dopant at the Ca2 site. Strong luminescence was observed for all Eu- and Gd-doped samples. Our multi-methodological study confirms that rare-earth (RE)-doped synthetic hydroxyapatites are promising materials for bio-imaging applications.

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Syntheses and crystal structures of trigonal rare-earth dioxymonocyanamides, Ln2O2CN2 (Ln=Dy, Ho, Er, Tm, Yb)

Powder Diffraction ◽

10.1154/1.2424475 ◽

2007 ◽

Vol 22 (1) ◽

pp. 59-63 ◽

Cited By ~ 8

Author(s):

Min Li ◽

Wenxia Yuan ◽

Jingfang Wang ◽

Cong Gu ◽

Huaizhou Zhao

Keyword(s):

Rare Earth ◽

Infrared Spectroscopy ◽

Solid State ◽

Rietveld Method ◽

Reaction Pathways ◽

X Ray Diffraction ◽

X Ray ◽

Cell Parameters ◽

Trigonal System ◽

Xrd Patterns

Trigonal rare-earth dioxymonocyanamides Ln2O2CN2 (Ln=Dy, Ho, Er, Tm, Yb) were synthesized by the modified solid-state metathesis (SSM) method, in which Ln2O3 and melamine C3N6H6 were mixed and heated at 850 °C in vacuumed silica ampoules. Possible chemical reaction pathways are proposed. X-ray diffraction (XRD) patterns of Ln2O2CN2 were refined using the Rietveld method. Compounds Ln2O2CN2 crystallize in the trigonal system with space group P3m1, Z=1, and cell parameters of a and c varying from 3.7267(1) to 3.6407(1) Å and from 8.1848(3) to 8.1152(3) Å, respectively, as Ln atoms change from Dy to Yb. These compounds have stacking structures of Ln2O22+ and CN22− layers, similar to those of previously reported compounds Ln2O2CN2 (Ln=Ce, Pr, Nd, Sm, Eu, Gd). The presence of CN22− ions has been confirmed by infrared spectroscopy, with two characteristic peaks in the vicinity of 651 and 2075 cm−1.

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New Ca2.90(Me2+)0.10(PO4)2 β-tricalcium Phosphates with Me2+ = Mn, Ni, Cu: Synthesis, Crystal-Chemistry, and Luminescence Properties

Crystals ◽

10.3390/cryst9060288 ◽

2019 ◽

Vol 9 (6) ◽

pp. 288 ◽

Cited By ~ 2

Author(s):

Angela Altomare ◽

Rosanna Rizzi ◽

Manuela Rossi ◽

Asmaa El Khouri ◽

Mohammed Elaatmani ◽

...

Keyword(s):

Tricalcium Phosphate ◽

Rietveld Method ◽

Unit Cell ◽

Luminescence Properties ◽

Luminescence Spectroscopy ◽

Luminescence Spectra ◽

Structural Refinement ◽

X Ray Diffraction ◽

X Ray ◽

Tricalcium Phosphates

C a 2.90 M e 0.10 2 + ( P O 4 ) 2 (with Me = Mn, Ni, Cu) β-tricalcium phosphate (TCP) powders were synthesized by solid-state reaction at T = 1200 °C and investigated by means of a combination of scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, and luminescence spectroscopy. SEM morphological analysis showed the run products to consist of sub spherical microcrystalline aggregates, while EDS semi-quantitative analysis confirmed the nominal Ca/Me composition. The unit cell and the space group were determined by X-ray powder diffraction data showing that all the compounds crystallize in the rhombohedral R3c whitlockite-type structure, with the following unit cell constants: a = b = 10.41014(19) Å, c = 37.2984(13) Å, and cell volume V = 3500.53(15) Å3 (Mn); a = b = 10.39447(10) Å, c = 37.2901(8) Å; V = 3489.22(9) Å3 (Ni); a = b = 10.40764(8) Å, c = 37.3158(6) Å, V = 3500.48(7) Å3 (Cu). The investigation was completed with the structural refinement by the Rietveld method. The FTIR spectra are similar to those of the end-member Ca β-tricalcium phosphate (TCP), in agreement with the structure determination, and show minor band shifts of the (PO4) modes with the increasing size of the replacing Me2+ cation. Luminescence spectra and decay curves revealed significant luminescence properties for Mn and Cu phases.

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X-ray powder diffraction data of LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites

Powder Diffraction ◽

10.1017/s0885715620000767 ◽

2021 ◽

pp. 1-6

Author(s):

Mariana M. V. M. Souza ◽

Alex Maza ◽

Pablo V. Tuza

Keyword(s):

Crystal Structure ◽

Rietveld Method ◽

Pechini Method ◽

Powder Diffraction Data ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Modified Pechini Method ◽

Scanning Electron

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.

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Crystal structure characterization and electronic structure of a rare-earth-containing Zintl phase in the Yb–Al–Sb family: Yb3AlSb3

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229621005192 ◽

2021 ◽

Vol 77 (6) ◽

Author(s):

Rongqing Shang ◽

An T. Nguyen ◽

Allan He ◽

Susan M. Kauzlarich

Keyword(s):

Crystal Structure ◽

Electronic Structure ◽

Rare Earth ◽

Electronic Structure Calculations ◽

Structure Characterization ◽

Charge Balance ◽

X Ray Diffraction ◽

Zintl Phase ◽

X Ray ◽

Structure Calculations

A rare-earth-containing compound, ytterbium aluminium antimonide, Yb3AlSb3 (Ca3AlAs3-type structure), has been successfully synthesized within the Yb–Al–Sb system through flux methods. According to the Zintl formalism, this structure is nominally made up of (Yb2+)3[(Al1−)(1b – Sb2−)2(2b – Sb1−)], where 1b and 2b indicate 1-bonded and 2-bonded, respectively, and Al is treated as part of the covalent anionic network. The crystal structure features infinite corner-sharing AlSb4 tetrahedra, [AlSb2Sb2/2]6−, with Yb2+ cations residing between the tetrahedra to provide charge balance. Herein, the synthetic conditions, the crystal structure determined from single-crystal X-ray diffraction data, and electronic structure calculations are reported.

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Structural Properties Analysis of Mg-β-TCP by X-ray Powder Diffraction with the Rietveld Refinement

Letters in Applied NanoBioScience ◽

10.33263/lianbs94.15621568 ◽

2020 ◽

Vol 9 (4) ◽

pp. 1562-1568

Keyword(s):

Powder Diffraction ◽

Rietveld Method ◽

Quantitative Phase Analysis ◽

Structural Refinement ◽

Osteoporosis Therapy ◽

X Ray ◽

Cell Parameters ◽

Biomineralization Process ◽

Resultant Powder ◽

Rapid Reaction

The incorporation of magnesium in the synthetic apatite has been associated with the biomineralization process and osteoporosis therapy in humans and animals. β-tricalcium phosphate (β-TCP) is one of the most common bioceramics widely applied in bone cement and implants. In this work, Ca-deficient apatite (CDA) with a theoretical 0.08 Mg/(Ca+Mg) ratio was synthesized by the rapid reaction between Ca(OH)2, MgCl2.6H2O and H3PO4 at 40°C and the resultant powder calcined at 650 °C for 10h. X-ray powder diffraction analysis (XRD), in combination with the Rietveld method (Fullprof-suite), was employed for quantitative phase analysis and structural refinement. The results of XRD indicate that magnesium can substitute for calcium into a β-TCP structure inducing a reduction of the cell parameters and the compound crystallizes in the rhombohedral R3c structure, with the following unit cell constants: a = b = 10.3560 Å, c = 37.1718 Å, and cell volume V = 3452.44. The analysis indicated that the substitution of Mg2+ on the M(4) and M(5) sites were, approximately, 2.61 and 6.97 mol%, corresponding to the Ca2.72(MgIV0.07, MgV0.21)(PO4)2 stoichiometric formula and 0.09 Mg/(Ca+Mg) ratio.

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X-ray diffraction studies on the effect of ball-milling speed on the structure of Cu(In,Ga)Se2 nanoparticles

Powder Diffraction ◽

10.1017/s088571561300033x ◽

2013 ◽

Vol 28 (S1) ◽

pp. S28-S31 ◽

Cited By ~ 3

Author(s):

L. Fu ◽

Y.Q. Guo ◽

S. Zheng

Keyword(s):

Ball Milling ◽

Least Squares Method ◽

Unit Cell ◽

Chalcopyrite Structure ◽

Structural Refinement ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Cigs Nanoparticles

Cu(In,Ga)Se2 (CIGS) semiconductors were prepared by arc melting and the vacuum solid reaction. CIGS nanoparticles were synthesized by the mechanical alloy method. The influences of various ball-milling speeds on phase structures for CIGS nanoparticles were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystal structures and unit-cell parameters of CIGS nanoparticles were determined using TREOR program and the least squares method. A Rietveld structural refinement was used to determine the atomic occupations and atomic numbers of CIGS prepared under various ball-milling speeds. The least size of agglomerated CIGS nanoparticles should be around 200 nm. CIGS nanoparticles milled at various milling speeds with a tetragonal chalcopyrite structure were obtained according to XRD analyses. However, Ga content in CIGS depends on milling speeds. Based on the structural refinements, the unit-cell parameters are a = 5.693(8)–5.744(9) Å and c = 11.334(9)–11.524(4) Å with gallium content ranging from 0.3 to 0.5. The atomic occupations are corresponding to the 4a crystal site for Cu atoms, the 4b site for In and the 8d site for Se. Ga prefers to occupy the 4b crystal site.

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Hydrothermal Synthesis ofβ-NaYF4:Yb, Er Nanocrystals with Upconversion Fluorescence Using Tetraethylene Pentamine as Chelating Ligand

Journal of Nanomaterials ◽

10.1155/2012/369605 ◽

2012 ◽

Vol 2012 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Suli Wu ◽

Yanhui Ning ◽

Shufen Zhang

Keyword(s):

Rare Earth ◽

Reaction Time ◽

Upconversion Luminescence ◽

Solvent Composition ◽

Luminescence Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Chelating Ligand ◽

Amine Groups ◽

Tetraethylene Pentamine

Novel chelating ligands are very significant for preparing nanocrystals with different morphologies and applications. In this paper, we directly introduced amine groups onto UCNPs by choosing a new chelating ligand tetraethylene pentamine (TEPA) to synthesisNaYF4:Yb, Er through hydrothermal method. The influences of rare earth concentration, the ratio of RE/TEPA, solvent composition, and reaction time on the morphology and fluorescence intensity of the as-preparedNaYF4:Yb, Er samples were systematically investigated and discussed. Field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), and upconversion luminescence spectroscopy were used to characterize the product. It was found that rare earth concentration, ratio of RE/TEPA, solvent composition, and reaction time were all responsible for the luminescent intensity and morphology.

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Structural analysis of excess-anion C-type rare earth oxide: a case study with Gd1−xCexO1.5+x/2(x= 0.20 and 0.40)

Journal of Applied Crystallography ◽

10.1107/s0021889803010288 ◽

2003 ◽

Vol 36 (4) ◽

pp. 1082-1084 ◽

Cited By ~ 33

Author(s):

V. Grover ◽

S. N. Achary ◽

A. K. Tyagi

Keyword(s):

Rare Earth ◽

Structural Analysis ◽

Metal Ion ◽

Rare Earth Oxide ◽

Charge Balance ◽

X Ray Diffraction ◽

X Ray ◽

Cell Parameters ◽

Lattice Space

Structural analysis of anion-rich C-type Gd2O3was carried by the Rietveld refinement of the powder X-ray diffraction data for compositions Gd0.8Ce0.2O1.60and Gd0.6Ce0.4O1.70. Both compounds have a body-centred cubic lattice (space groupIa\bar{3}, No. 206,Z= 32) with unit-cell parameters of 10.8488 (1) and 10.8542 (1) Å, respectively. Both of these compounds are iso-structural with the C-type rare earth oxides, with excess anions as required for charge balance. The structural analysis reveals that there are two different kinds of metal ion site, namely 8b(M1) and 24d(M2), and two different kinds of anion sites, namely 48e(O1) and 16c(O2). The excess anions occupy the 16c(xxx) sites. The two metal ions each form an approximately eightfold-coordination polyhedron with O1 and O2. The details of these two compositions are explained and compared with both the CeO2structure and the Gd2O3structure,i.e.the end member.

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X-ray Diffraction Study of the Crystal Structure of the Tl Ternary Chalcogenides Tl2x In2(1−x)Se2, x = 0.2, 0.3,...0.9

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768197017886 ◽

1998 ◽

Vol 54 (4) ◽

pp. 358-364 ◽

Cited By ~ 6

Author(s):

K. G. Hatzisymeon ◽

S. C. Kokkou ◽

A. N. Anagnostopoulos ◽

P. I. Rentzeperis

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Rietveld Method ◽

Direct Methods ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

Single Crystal Diffraction ◽

X Ray ◽

Cell Parameters ◽

Volume Decrease

A series of thallium ternary chalcogenides with the composition Tl2x In2(1−x)Se2, x = 0.2, 0.3,...0.9, have been studied by X-ray powder and, for some of them, single-crystal diffraction. They are tetragonal, space group I4/mcm, Z = 4, and isostructural with the binary semiconductor TlSe. Their crystal structures have been solved by direct methods and refined by the Rietveld method to a precision which is satisfactorily comparable to single-crystal results. As x is changed from x = 0.2 to x = 0.9 the unit-cell parameters and volume decrease or increase following Kurnakov's law, which is valid for solid solutions. Refined positional parameters of Se, In—Se and Tl—Se bond lengths vary with x also according to the same law. The distribution of In and Tl cations in 4(a) and 4(b) sites depends on the stoichiometry x and the crystals are composed of [In3+Se2]_{\infty}^- chains along the c axis in which InSe4 tetrahedra share edges; the chains are interconnected with Tl+(In+) ions.

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Synthesis and characterization of Na-P1 (GIS) zeolite using a kaolinitic rock

10.21203/rs.3.rs-111813/v1 ◽

2020 ◽

Author(s):

Daniela Novembre ◽

Domingo Gimeno ◽

Alessandro Del Vecchio

Keyword(s):

Inductively Coupled Plasma ◽

Rietveld Method ◽

Ambient Pressure ◽

Optical Emission ◽

Emission Spectrometry ◽

Quantitative Phase Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Cell Parameters ◽

Inductively Coupled

Abstract This work focuses on the hydrothermal synthesis of Na-P1 zeolite by using a kaolinite rock coming from Romana (Sassari, Italy). The kaolin is calcined at a temperature of 650 °C and then mixed with calculated quantities of NaOH. The synthesis runs are carried out at ambient pressure and at variable temperatures of 65 ° and 100 °C. For the first time compared to the past, the Na-P1 zeolite is synthesized without the use of additives and through a protocol that reduces both temperatures and synthesis times. The synthesis products are analysed by X-ray diffraction, high temperature X-ray diffraction, infrared spectroscopy, scanning electron microscopy and inductively coupled plasma optical emission spectrometry. The cell parameters are calculated using the Rietveld method. Density and specific surface area are also calculated. The absence of amorphous phases and impurities in synthetic powders is verified through quantitative phase analysis using the combined Rietveld and reference intensity ratio methods.The results make the experimental protocol very promising for an industrial transfer.

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