Nothing Special   »   [go: up one dir, main page]
You seem to have javascript disabled. Please note that many of the page functionalities won't work as expected without javascript enabled.
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.1
2.2
Journals
Minerals
Special Issues
Minerals as Advanced Materials
share announcement

Minerals as Advanced Materials

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Crystallography and Physical Chemistry of Minerals & Nanominerals".

Deadline for manuscript submissions: closed (1 May 2022) | Viewed by 5327

Special Issue Editor

Dr. Oleg I. Siidra

E-Mail Website
Guest Editor
Department of Crystallography, Saint-Petersburg State University, University emb. 7/9, 199034 St. Petersburg, Russia
Interests: minerals; Earth sciences; crystallography; X-ray diffraction; inorganic chemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Minerals have been of great interest to chemists and physicists. The disadvantage of minerals is the presence of impurities that hamper or even preclude the study of physical properties on natural samples. However, the discovery of minerals with new structures and chemical compositions facilitates the identification of new chemical compounds that can be later prepared in the lab and put under the scrutiny of the physical characterization. This approach “from minerals to materials” avoids the trial-and-error method, often used in an exploratory synthesis, and may be advantageous over computational predictions of thermodynamic stability that can be biased by inaccuracies of the computational methods.

This Special Issue welcomes contributions on minerals and their synthetic analogues, new mineral species with potentially interesting applications, mineralogical crystallography, synthesis of mineral-related compounds, and properties of mineral-related inorganic materials.

Dr. Oleg I. Siidra
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • minerals
  • synthetic mineral analogues
  • materials
  • crystal structure
  • inorganic synthesis
  • structure-property relationships

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (2 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

20 pages, 25170 KiB  
Article
Ion-Exchange-Induced Transformation and Mechanism of Cooperative Crystal Chemical Adaptation in Sitinakite: Theoretical and Experimental Study
by Taras L. Panikorovskii, Galina O. Kalashnikova, Anatoly I. Nikolaev, Igor A. Perovskiy, Ayya V. Bazai, Victor N. Yakovenchuk, Vladimir N. Bocharov, Natalya A. Kabanova and Sergey V. Krivovichev
Minerals 2022, 12(2), 248; https://doi.org/10.3390/min12020248 - 15 Feb 2022
Cited by 5 | Viewed by 2867
Abstract
The microporous titanosilicate sitinakite, KNa2Ti4(SiO4)2O5(OH)·4H2O, was first discovered in the Khibiny alkaline massif. This material is also known as IONSIV IE-911 and is considered as one of the most effective sorbents [...] Read more.
The microporous titanosilicate sitinakite, KNa2Ti4(SiO4)2O5(OH)·4H2O, was first discovered in the Khibiny alkaline massif. This material is also known as IONSIV IE-911 and is considered as one of the most effective sorbents for Cs+ and Sr2+ from water solutions. We investigate a mechanism of cooperative crystal chemical adaptation caused by the incorporation of La3+ ions into sitinakite structure by the combination of theoretical (geometrical–topological analysis, Voronoi migration map calculation, structural complexity calculation) and empirical methods (PXRD, SCXRD, Raman spectroscopy, scanning electron microscopy). The natural crystals of sitinakite (a = 7.8159(2), c = 12.0167(3) Å) were kept in a 1M solution of La(NO3)3 for 24 h. The ordering of La3+ cations in the channels of the ion-exchanged form La3+Ti4(SiO4)2O5(OH)·4H2O (a = 11.0339(10), b = 11.0598(8), c = 11.8430(7) Å), results in the symmetry breaking according to the group–subgroup relation P42/mcm → Cmmm. Full article
(This article belongs to the Special Issue Minerals as Advanced Materials)
►▼ Show Figures

Figure 1

Figure 1
<p>(<b>a</b>) Geology of the Khibiny massif and Mt. Koashva within purple star after [<a href="#B46-minerals-12-00248" class="html-bibr">46</a>] with modifications; (<b>b</b>) the Koashva quarry, Khibiny alkaline massif, Kola Peninsula, Russia. The purple star indicates the location for the sitinakite bearing vein no. 8; (<b>c</b>) short-prismatic sitinakite (1) crystals with aegirine needles (2) and amorphous bitumens (3).</p> Full article ">Figure 2
<p>Backscattered images of (<b>a</b>) La-exchanged natural sitinakite (1) at 200 °C for 24 h with aegirine (2) inclusion; (<b>b</b>) synthetic La-exchanged sitinakite at 200 °C for 24 h; (<b>c</b>) formation of anatase (3) crusts on the surface of synthetic La-exchanged sitinakite at 200 °C for 24 h.</p> Full article ">Figure 3
<p>Raman spectra of initial sitinakite and La-exchanged natural sitinakite. The most significant differences in the positions or intensity in both spectra are indicated by gray lines.</p> Full article ">Figure 4
<p>Calculated powder XRD pattern of initial sitinakite and La-exchanged form.</p> Full article ">Figure 5
<p>Diffraction patterns of synthetic sitinakite and its La-exchanged forms after 1, 4, 12 and 24 h sorption at 200 °C. The most significant differences in the positions or intensity in both patterns are indicated by the gray rectangles.</p> Full article ">Figure 6
<p>Reconstructed sections of reciprocal space obtained for the (<span class="html-italic">hk</span>0) and (<span class="html-italic">h</span>0<span class="html-italic">l</span>) sections for sitinakite (<b>a</b>,<b>c</b>) and its La-exchanged form (<b>b</b>,<b>d</b>) and enlarged fragments of these sections (<b>e</b>–<b>g</b>). White arrows and numbers indicate reflections and their indices. The examples of additional reflections, which cannot be indexed in the tetragonal cell are indicated by question marks. On the corresponding schemas, large dark red circles and small unfilled circles belong to the tetragonal (<span class="html-italic">a</span> = 7.8159, <span class="html-italic">c</span> = 12.0167 Å) and orthorhombic (<span class="html-italic">a</span> = 11.0339, <span class="html-italic">b</span> = 11.0598, <span class="html-italic">c</span> = 11.8430 Å) cells, respectively; black and red arrows indicate tetragonal and orthorhombic cell vectors, respectively.</p> Full article ">Figure 7
<p>The crystal structure of sitinakite projected along the <span class="html-italic">c</span> axis (<b>a</b>); the [Ti<sub>4</sub>O<sub>4</sub>]<sup>8+</sup><sub>∞</sub> column with adjacent SiO<sub>4</sub> tetrahedra in sitinakite (<b>b</b>); the connection of [Ti<sub>4</sub>O<sub>4</sub>]<sup>8+</sup> clusters in ivanyukite-K [<a href="#B17-minerals-12-00248" class="html-bibr">17</a>] (<b>c</b>); the channel I defined by an 8-membered ring (<b>d</b>), the 6-membered rings of the channels II (<b>e</b>) and III (<b>f</b>) with Na and K atoms in the sitinakite structure.</p> Full article ">Figure 8
<p>The crystal structure of La-exchanged sitinakite projected along <span class="html-italic">c</span> axis with channel I (<b>a</b>); along [110] direction with channel III (<b>b</b>); along <span class="html-italic">a</span> axis with channel II (<b>c</b>); coordination of La1, La2, La3, Si1, Ti1 and Ti2 atoms (<b>d</b>). The occupancy La-sites are indicated by different sectors filled by the green color.</p> Full article ">Figure 9
<p>Tiling representation of the titanosilicate framework in the crystal structure of sitinakite. The unit cell is outlined.</p> Full article ">Figure 10
<p>The small t-kzd, t-lov, t-cub tiles (<b>a</b>) and the large new tile [4<sup>8</sup>.6<sup>6</sup>.8<sup>2</sup>] in the crystal structure of sitinakite. Na, K and La cations are located within the large tile (<b>b</b>).</p> Full article ">Figure 11
<p>Migration paths for Na and K (<b>a</b>) for sitinakite and La (<b>b</b>) for La-exchanged form.</p> Full article ">Figure 12
<p>Largest cavity corresponding to the tile [4<sup>8</sup>.6<sup>6</sup>.8<sup>2</sup>]: in sitinakite with the Na2 site (<b>a</b>); in La-exchanged sitinakite with the La1 site (<b>b</b>); in La-exchanged sitinakite with La3 site (<b>c</b>); the hinge-like deformation in the Ti1O<sub>6</sub> octahedra associated with the La1 site (<b>d</b>); and associated with the La3 site (<b>e</b>). Green and grey arrows represent distortions caused by the La incorporation.</p> Full article ">Figure 13
<p>The modulated character of low-occupied H<sub>2</sub>O sites along [010] direction associated with La1 sites.</p> Full article ">
9 pages, 3862 KiB  
Article
Whitlockite-Type Structure as a Matrix for Optical Materials: Synthesis and Characterization of Novel TM-SM Co-Doped Phosphate Ca9Gd(PO4)7, a Single-Phase White Light Phosphors
by Ivan V. Nikiforov, Dina V. Deyneko, Dmitry A. Spassky, Bogdan I. Lazoryak and Sergey M. Aksenov
Minerals 2022, 12(1), 76; https://doi.org/10.3390/min12010076 - 9 Jan 2022
Viewed by 1570
Abstract
A series of novel phosphates with the general formulas Ca9Gd0.9−xTm0.1Smx(PO4)7 and Ca9Gd0.9−yTmySm0.1(PO4)7 were synthesized by solid-state method. As-obtained phosphates [...] Read more.
A series of novel phosphates with the general formulas Ca9Gd0.9−xTm0.1Smx(PO4)7 and Ca9Gd0.9−yTmySm0.1(PO4)7 were synthesized by solid-state method. As-obtained phosphates were characterized by powder X-ray diffraction and second harmonic generation analyses, dielectric measurements, luminescence spectroscopy. All samples were single phase and characterized by the whitlockite-type structure with space group R3c. An influence of admixture concentration of REE3+ ions in the initial host on dielectric properties was studied in details. Synthesized phosphates are characterized by intensive luminescence. The emission in the orange region of the visible spectrum is observed for Ca9Gd0.9Sm0.1(PO4)7 with a maximum intensity band at 602 nm. The line in blue region at 455 nm, which corresponds to 1D2 → 3F4 Tm3+ transition, is registered for Ca9Gd0.9Tm0.1(PO4)7. Emission in the white region of CIE coordinates was registered for Tm-Sm co-doped compounds. Full article
(This article belongs to the Special Issue Minerals as Advanced Materials)
►▼ Show Figures

Figure 1

Figure 1
<p>PXRD patterns for Ca<sub>9</sub>Gd<sub>0.9−<span class="html-italic">x</span></sub>Tm<sub>0.1</sub>Sm<span class="html-italic"><sub>x</sub></span>(PO<sub>4</sub>)<sub>7</sub> (<span class="html-italic">x</span> = 0 (1); 0.2 (2); 0.3 (3)) and Ca<sub>9</sub>Gd<sub>0.9−<span class="html-italic">y</span></sub>Tm<span class="html-italic"><sub>y</sub></span>Sm<sub>0.1</sub>(PO<sub>4</sub>)<sub>7</sub> (<span class="html-italic">y</span> = 0 (4); 0.1 (5); 0.2 (6)) with Bragg reflections for Ca<sub>9</sub>Dy(PO<sub>4</sub>)<sub>7</sub> (PDF Card No 49-1086).</p> Full article ">Figure 2
<p>Dependence of the unit cell volumes of Ca<sub>9</sub>Gd<sub>0.9−<span class="html-italic">x</span></sub>Tm<sub>0.1</sub>Sm<span class="html-italic"><sub>x</sub></span>(PO<sub>4</sub>)<sub>7</sub> (1) and Ca<sub>9</sub>Gd<sub>0.9−<span class="html-italic">y</span></sub>Tm<span class="html-italic"><sub>y</sub></span>Sm<sub>0.1</sub>(PO<sub>4</sub>)<sub>7</sub> (2) on the concentration of REE, and the unit cell volume of pure Ca<sub>9</sub>Gd(PO<sub>4</sub>)<sub>7</sub> (3).</p> Full article ">Figure 3
<p>The SEM image for Ca<sub>9</sub>Gd<sub>0.8</sub>Tm<sub>0.1</sub>Sm<sub>0.1</sub>(PO<sub>4</sub>)<sub>7</sub>.</p> Full article ">Figure 4
<p>Temperature dependence of the dielectric permittivity ε (<b>a</b>) and dielectric loss tangent tan δ (<b>b</b>) for Ca<sub>9</sub>Gd(PO<sub>4</sub>)<sub>7</sub>.</p> Full article ">Figure 5
<p>(<b>a</b>) PLE (<span class="html-italic">λ<sub>em</sub></span> = 602 nm) and (<b>b</b>) PL (<span class="html-italic">λ<sub>ex</sub></span> = 404 nm) spectra for Ca<sub>9</sub>Gd<sub>0.9</sub>Sm<sub>0.1</sub>(PO<sub>4</sub>)<sub>7</sub>.</p> Full article ">Figure 6
<p>(<b>a</b>) PLE (<span class="html-italic">λ<sub>em</sub></span> = 477 nm) and (<b>b</b>) PL (<span class="html-italic">λ<sub>ex</sub></span> = 356 nm) spectra for Ca<sub>9</sub>Gd<sub>0.9</sub>Tm<sub>0.1</sub>(PO<sub>4</sub>)<sub>7</sub>.</p> Full article ">Figure 7
<p>PL spectrum of Ca<sub>9</sub>Gd<sub>0.8</sub>Tm<sub>0.1</sub>Sm<sub>0.1</sub>(PO<sub>4</sub>)<sub>7</sub>, <span class="html-italic">λ<sub>ex</sub></span> = 356 nm.</p> Full article ">Figure 8
<p>Integrated intensity of Tm<sup>3+</sup> (1) and Sm<sup>3+</sup> (2) emissions for Ca<sub>9</sub>Gd<sub>0.9−<span class="html-italic">x</span></sub>Tm<sub>0.1</sub>Sm<span class="html-italic"><sub>x</sub></span>(PO<sub>4</sub>)<sub>7</sub> (<b>a</b>) and Ca<sub>9</sub>Gd<sub>0.9−<span class="html-italic">y</span></sub>Tm<span class="html-italic"><sub>y</sub></span>Sm<sub>0.1</sub>(PO<sub>4</sub>)<sub>7</sub> (<b>b</b>) at <span class="html-italic">λ<sub>ex</sub></span> = 356 nm.</p> Full article ">Figure 9
<p>Color coordinates for Ca<sub>9</sub>Gd<sub>0.9−<span class="html-italic">x</span></sub>Tm<sub>0.1</sub>Sm<span class="html-italic"><sub>x</sub></span>(PO<sub>4</sub>)<sub>7</sub> <span class="html-italic">x</span> = 0 (1), <span class="html-italic">x</span> = 0.1 (2), <span class="html-italic">x</span> = 0.2 (3), <span class="html-italic">x</span> = 0.3 (4) and Ca<sub>9</sub>Gd<sub>0.9</sub>Sm<sub>0.1</sub>(PO<sub>4</sub>)<sub>7</sub> (5).</p> Full article ">
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-2
Back to TopTop