Catapleiite behavior under heating and crystal structure of the product of its high-temperature transformation — the new phase Na6Zr3[Si9O27] with nine-membered rings of Si—O-tetrahedra

AbstractThe mixed cation triel borate Ga4In4B15O33(OH)3 was synthesized in a Walker-type multianvil apparatus at high-pressure/high-temperature conditions of 12.5 GPa and 1300°C. Although the product could not be reproduced in further experiments, its crystal structure could be reliably determined via single-crystal X-ray diffraction data. Ga4In4B15O33(OH)3 crystallizes in the tetragonal space group I41/a (origin choice 2) with the lattice parameters a = 11.382(2), c = 15.244(2) Å, and V = 1974.9(4) Å3. The structure of the quaternary triel borate consists of a complex network of BO4 tetrahedra, edge-sharing InO6 octahedra in dinuclear units, and very dense edge-sharing GaO6 octahedra in tetranuclear units.

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Photoluminescence Properties of Ca3Si2O7: Pr3+ Orange-Red Phosphors Prepared by High-Temperature Solid-State Method

Zeitschrift für Naturforschung A ◽

10.1515/zna-2018-0050 ◽

2018 ◽

Vol 73 (6) ◽

pp. 555-558 ◽

Cited By ~ 3

Author(s):

Zhi-Qing Peng ◽

Rong Chen ◽

Wen-Lin Feng

Keyword(s):

Crystal Structure ◽

High Temperature ◽

Solid State ◽

Solid State Method ◽

Light Emitting ◽

Light Emitting Devices ◽

Red Phosphors ◽

Typical Sample ◽

State Method ◽

Xrd Patterns

AbstractNovel luminescent materials Ca3-xSi2O7: xPr3+ were successfully prepared by the high-temperature solid-state method. The crystal structure, morphology, and optical spectrum were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectroscopy, respectively. The XRD patterns of the samples indicate that the crystal structure is monoclinic symmetry. The SEM shows that the selected sample has good crystallinity although its appearance is irregular and scalelike. The peak of the excitation spectrum of the sample is located at around 449 nm, corresponding to 3H4→3P2 transition of Pr3+. The peak of the emission spectrum of the sample is situated at around 612 nm which is attributed to 3P0→3H6 transition of Pr3+, and the colour is orange-red. The optimum concentration for Pr3+ replaced Ca2+ sites in Ca3Si2O7: Pr3+ is 0.75 mol%. The lifetime (8.48 μs) of a typical sample (Ca2.9925Pr0.0075)Si2O7 is obtained. It reveals that orange-red phosphors Ca3-xSi2O7: xPr3+ possess remarkable optical properties and can be used in white light emitting devices.

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Crystal and powder XRD data of Mg3(PO4)2-III: High-temperature and high-pressure form

Powder Diffraction ◽

10.1017/s0885715600015013 ◽

1995 ◽

Vol 10 (4) ◽

pp. 293-295 ◽

Cited By ~ 1

Author(s):

F. Brunet ◽

C. Chopin ◽

A. Elfakir ◽

M. Quarton

Keyword(s):

Crystal Structure ◽

High Pressure ◽

High Temperature ◽

Single Crystal ◽

Diffraction Pattern ◽

Structure Refinement ◽

Powder Xrd ◽

Single Crystal Structure ◽

Crystal Structure Refinement ◽

Pressure Form

A new diffraction pattern of the high-temperature and high-pressure polymorph Mg3(PO4)2-III (PDF 43-500) is given and indexed on the basis of a single-crystal structure refinement. It allows diffractogram indexing of the isostructural high-temperature and high-pressure form of Co3(PO4)2 (PDF 43-499).

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High temperature-high pressure synthesis of a new phase of LaCuO3

Physics Letters A ◽

10.1016/0375-9601(89)90212-0 ◽

1989 ◽

Vol 137 (4-5) ◽

pp. 205-206 ◽

Cited By ~ 19

Author(s):

A.W. Webb ◽

E.F. Skelton ◽

S.B. Qadri ◽

E.R. Carpenter ◽

M.S. Osofsky ◽

...

Keyword(s):

High Pressure ◽

High Temperature ◽

High Pressure Synthesis ◽

Pressure Synthesis ◽

New Phase ◽

High Temperature High Pressure

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Crystal structure, chemical expansion and phase stability of HoMnO3 at high temperature

Journal of Solid State Chemistry ◽

10.1016/j.jssc.2012.07.024 ◽

2012 ◽

Vol 196 ◽

pp. 528-535 ◽

Cited By ~ 16

Author(s):

Sverre M. Selbach ◽

Amund Nordli Løvik ◽

Kristin Bergum ◽

Julian R. Tolchard ◽

Mari-Ann Einarsrud ◽

...

Keyword(s):

Crystal Structure ◽

High Temperature ◽

Phase Stability ◽

Chemical Expansion

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In Situ High-Temperature Transmission Electron Microscopy Observations of the Formation of Nanocrystalline TiC from Nanocrystalline Anatase (TiO2)

Microscopy and Microanalysis ◽

10.1017/s1431927698980278 ◽

1998 ◽

Vol 4 (3) ◽

pp. 269-277 ◽

Cited By ~ 8

Author(s):

A. Agrawal ◽

J. Cizeron ◽

V.L. Colvin

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Temperature ◽

Solid Phase ◽

Anatase Phase ◽

High Resolution Electron Microscopy ◽

Rutile Phase ◽

Transmission Electron ◽

New Phase

In this work, the high-temperature behavior of nanocrystalline TiO2 is studied using in situ transmission electron microscopy (TEM). These nanoparticles are made using wet chemical techniques that generate the anatase phase of TiO2 with average grain sizes of 6 nm. X-ray diffraction studies of nanophase TiO2 indicate the material undergoes a solid-solid phase transformation to the stable rutile phase between 600° and 900°C. This phase transition is not observed in the TEM samples, which remain anatase up to temperatures as high as 1000°C. Above 1000°C, nanoparticles become mobile on the amorphous carbon grid and by 1300°C, all anatase diffraction is lost and larger (50 nm) single crystals of a new phase are present. This new phase is identified as TiC both from high-resolution electron microscopy after heat treatment and electron diffraction collected during in situ heating experiments. Video images of the particle motion in situ show the nanoparticles diffusing and interacting with the underlying grid material as the reaction from TiO2 to TiC proceeds.

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