Cation movement and phase transitions in KTP isostructures; X-ray study of sodium-doped KTP at 10.5 K

An accurate structure model of sodium-doped potassium titanyl phosphate, (Na0.114K0.886)K(TiO)2(PO4)2, has been determined at 10.5 K by single-crystal X-ray diffraction. In addition to the low-temperature data, X-ray intensities have been collected at room temperature. When the temperature was decreased from room temperature to 10.5 K, both potassium cations moved 0.033 (2) Å along the c-axis, i.e. in the polar direction within the rigid Ti—O—P network. This alkaline metal ion displacement can be related to the Abrahams–Jamieson–Kurtz T C criteria for oxygen framework ferroelectrics. Potassium titanyl phosphate (KTP) is a well known material for second harmonic generation (SHG), and the influence of sodium dopant on the TiO6 octahedral geometry and SHG is discussed. The material studied crystallizes in the space group Pna21 with Z = 4, a = 12.7919 (5), b = 6.3798 (4), c = 10.5880 (7) Å, V = 864.08 (9) Å3, T = 10.5 (3) K and R = 0.023.

Download Full-text

The α-phase of SrTeO3 at 295 K

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s160053680700164x ◽

2007 ◽

Vol 63 (3) ◽

pp. i75-i76 ◽

Cited By ~ 7

Author(s):

Valery E. Zavodnik ◽

Sergey A. Ivanov ◽

Adam I. Stash

Keyword(s):

Room Temperature ◽

Second Harmonic ◽

Czochralski Method ◽

Structure Model ◽

X Ray Diffraction ◽

X Ray ◽

Α Phase ◽

Oxygen Anions ◽

Generation Test ◽

Selection Of

The crystal structure of strontium tellurite (STO), SrTeO3, has been determined at room temperature using X-ray diffraction data obtained from single crystals grown by the Czochralski method. Selection of a non-centrosymmetric (C2) structure model was confirmed by the second harmonic generation test. The structure of STO is built up of three types of distorted [SrO x ] polyhedra (x = 6, 7 and 8) which share their oxygen anions with TeO3 pyramidal units. These main anionic polyhedra are responsible for establishing two types of tunnels required for the electron lone pairs of the Te4+ cation.

Download Full-text

Crystal structure of apatite type Ca2.49Nd7.51(SiO4)6O1.75

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s205698901600089x ◽

2016 ◽

Vol 72 (2) ◽

pp. 209-211 ◽

Cited By ~ 3

Author(s):

Thu Hoai Le ◽

Neil R. Brooks ◽

Koen Binnemans ◽

Bart Blanpain ◽

Muxing Guo ◽

...

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Room Temperature ◽

Solubility Limit ◽

Temperature Data ◽

X Ray Diffraction ◽

Slow Cooling ◽

X Ray ◽

Natural Apatite ◽

Apatite Type

The title compound, Ca2+xNd8–x(SiO4)6O2–0.5x(x= 0.49), was synthesized at 1873 K and rapidly quenched to room temperature. Its structure has been determined using single-crystal X-ray diffraction and compared with results reported using neutron and X-ray powder diffraction from samples prepared by slow cooling. The single-crystal structure from room temperature data was found to belong to the space groupP63/mand has the composition Ca2.49Nd7.51(SiO4)6O1.75[dicalcium octaneodymium hexakis(orthosilicate) dioxide], being isotypic with natural apatite and the previously reported Ca2Nd8(SiO4)6O2and Ca2.2Nd7.8(SiO4)6O1.9. The solubility limit of calcium in the equilibrium state at 1873 K was found to occur at a composition of Ca2+xNd8–x(SiO4)6O2–0.5x, wherex= 0.49.

Download Full-text

Analysis of LiKSO4 crystals in the temperature range from 573 to 943 K

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768100003219 ◽

2000 ◽

Vol 56 (4) ◽

pp. 607-617 ◽

Cited By ~ 20

Author(s):

Carlos Basílio Pinheiro ◽

Marcos Assunção Pimenta ◽

Gervais Chapuis ◽

Nivaldo Lúcio Speziali

Keyword(s):

Single Crystal ◽

Phase Ii ◽

Room Temperature ◽

Structure Model ◽

Structural Studies ◽

X Ray Diffraction ◽

X Ray ◽

Atomic Displacements ◽

Disordered Models ◽

Different Temperatures

The structural phases observed in LiKSO_4 crystals due to thermotropic transitions have been studied for more than a century. Nowadays many different phases are referenced, but some of the results are still controversial. Structural studies by single-crystal X-ray diffraction from room temperature to 803 K are presented here. Phase II (708 \lt T \lt 943 K) is extensively discussed on the basis of ordered and disordered models, using harmonic and anharmonic atomic displacements, and considering a twinned crystal composed of three orthorhombic domains. Analyses of the same phase at different temperatures determine the best structure model.

Download Full-text

A redetermination of the structure and Hirshfeld surface analysis of poly[diaquadi-μ-hydroxido-tetrakis(μ-nicotinato N-oxide)tricopper(II)]

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989021002000 ◽

2021 ◽

Vol 77 (3) ◽

pp. 309-313

Author(s):

Masoud Mirzaei ◽

Maryam Bazargan ◽

Pouria Ebtehaj ◽

Joel T. Mague

Keyword(s):

Low Temperature ◽

Dicarboxylic Acid ◽

Surface Analysis ◽

Room Temperature ◽

Temperature Data ◽

Hirshfeld Surface ◽

Hirshfeld Surface Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Naoh Solution

The product obtained from the reaction of pyridine-2,3-dicarboxylic acid and hydrated copper(II) chloride in hot aqueous NaOH solution was determined by low temperature X-ray diffraction to be [Cu3(C6H4NO3)4(OH)2(H2O)2] n or [Cu3(μ-OH)2(μ-nicNO)4(H2O)2] n (nicNO is pyridine-3-carboxylate N-oxide), a structure obtained from room temperature data and reported previously. The present determination is improved in quality and treatment of the H atoms. A Hirshfeld surface analysis of the intermolecular interactions is presented.

Download Full-text

Growth Studies and X-Ray Topographical Assessment of KTP

MRS Proceedings ◽

10.1557/proc-329-23 ◽

1993 ◽

Vol 329 ◽

Cited By ~ 4

Author(s):

K B Hutton ◽

R C C Ward ◽

K W Godfrey

Keyword(s):

Optical Transmission ◽

Temperature Data ◽

Potassium Titanyl Phosphate ◽

X Ray Diffraction ◽

Slow Cooling ◽

X Ray ◽

Growth Defects ◽

Growth Method ◽

Growth Quality ◽

Synthesis, Characterisation, and X-Ray Crystal Structures of 8-Hydroxyquinoline Complexes of Group IV Metal Alkoxides

Australian Journal of Chemistry ◽

10.1071/ch13420 ◽

2013 ◽

Vol 66 (12) ◽

pp. 1587

Author(s):

Mahsa Armaghan ◽

Mahdi Mirzaee ◽

Mahmood Norouzi ◽

Mostafa M. Amini ◽

Hamid Reza Khavasi

Keyword(s):

Metal Ion ◽

Room Temperature ◽

Group Iv ◽

Molecular Structures ◽

X Ray Diffraction ◽

X Ray ◽

Pyridine Nitrogen ◽

Distorted Octahedral ◽

Stoichiometric Reaction ◽

Alkoxy Groups

Stoichiometric reaction of 8-hydroxyquinoline with titanium tetraethoxide, and zirconium and hafnium tetra-2-propoxide in toluene at room temperature resulted in formation of [M2-μ-(OR)2-(C9H6NO)2(OR)2] (1: M = Ti, R = Et; 2: M = Zr, R = iPr; 3: M = Hf, R = iPr). All complexes were characterised by infrared, ultraviolet-visible, and NMR spectroscopy, and mass spectrometry. The molecular structures of 1, 2, and 3 were determined by single-crystal X-ray diffraction. The coordination geometries around the metal ions are distorted octahedral, which share an edge through bridged alkoxy groups. Each anionic 8-quinolinolate ligand is also chelated to one metal ion through its pyridine nitrogen and phenolate oxygen atoms.

Download Full-text

Electron Microscopy of Human Gallstones

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065523 ◽

1971 ◽

Vol 29 ◽

pp. 296-297

Author(s):

C. Wolpers ◽

R. Blaschke

Keyword(s):

Electron Microscopy ◽

Room Temperature ◽

Bile Pigment ◽

X Ray Diffraction ◽

Triclinic Crystal System ◽

X Ray ◽

Follow Up Study ◽

Infra Red ◽

Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

Download Full-text

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173996 ◽

1990 ◽

Vol 48 (4) ◽

pp. 172-173

Author(s):

Naoki Yamamoto ◽

Makoto Kikuchi ◽

Tooru Atake ◽

Akihiro Hamano ◽

Yasutoshi Saito

Keyword(s):

Phase Transition ◽

Electron Microscope Study ◽

Room Temperature ◽

Hexagonal Lattice ◽

Ferroelectric Materials ◽

Temperature Phase ◽

X Ray Diffraction ◽

X Ray ◽

Periodic Arrays ◽

Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

Download Full-text

Xenon Trioxide Adducts of O-Donor Ligands; [(CH3)2CO]3XeO3, [(CH3)2SO]3(XeO3)2, (C5H5NO)3(XeO3)2, and [(C6H5)3PO]2XeO3

10.26434/chemrxiv.7092263.v1 ◽

2018 ◽

Author(s):

Katherine Marczenko ◽

James Goettel ◽

Gary Schrobilgen

Keyword(s):

Room Temperature ◽

Triphenylphosphine Oxide ◽

Donor Ligands ◽

Mechanical Shock ◽

X Ray Diffraction ◽

X Ray ◽

Oxygen Coordination ◽

Xenon Trioxide ◽

Distorted Octahedra ◽

Coordination Spheres

Oxygen coordination to the Xe(VI) atom of XeO3 was observed in its adducts with triphenylphosphine oxide, dimethylsulfoxide, pyridine-N-oxide, and acetone. The crystalline adducts were characterized by low-temperature, single-crystal X-ray diffraction and Raman spectroscopy. Unlike solid XeO3, which detonates when mechanically or thermally shocked, the solid [(C6H5)3PO]2XeO3, [(CH3)2SO]3(XeO3)2, and (C5H5NO)3(XeO3)2 adducts are insensitive to mechanical shock, but undergo rapid deflagration when ignited by a flame. Both [(C6H5)3PO]2XeO3 and (C5H5NO)3(XeO3)2 are air-stable whereas [(CH3)2SO]3(XeO3)2 slowly decomposes over several days and [(CH3)2CO]3XeO3 undergoes adduct dissociation at room temperature. The xenon coordination sphere of [(C6H5)3PO]2XeO3 is a distorted square pyramid which provides the first example of a five-coordinate XeO3 adduct. The xenon coordination spheres of the remaining adducts are distorted octahedra comprised of three Xe---O secondary contacts that are approximately trans to the primary Xe–O bonds of XeO3. Quantum-chemical calculations were used to assess the Xe---O adduct bonds, which are predominantly electrostatic σ-hole bonds between the nucleophilic oxygen atoms of the bases and the σ-holes of the xenon atoms.

Download Full-text

Effect of trytophan as dopant on potassium acid phthalate single crystals

10.31221/osf.io/cn28k ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Single Crystals ◽

Room Temperature ◽

Visible Region ◽

X Ray Diffraction ◽

X Ray ◽

Slow Evaporation Technique ◽

Absorption Studies ◽

Evaporation Technique ◽

Potassium Acid Phthalate ◽

Acid Phthalate

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.

Download Full-text