Crystallization of sodium molybdate-phosphate and tungstate-phosphate glasses

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F18%3A39912722" target="_blank" >RIV/00216275:25310/18:39912722 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.jnoncrysol.2017.09.040" target="_blank" >http://dx.doi.org/10.1016/j.jnoncrysol.2017.09.040</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jnoncrysol.2017.09.040" target="_blank" >10.1016/j.jnoncrysol.2017.09.040</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Crystallization of sodium molybdate-phosphate and tungstate-phosphate glasses

Popis výsledku v původním jazyce

The glass to crystal transformation was studied for two glasses with composition 25Na(2)center dot O.50MoO(3)center dot 25P(2)O(6) and 25Na(2)O center dot 50WO(3)center dot 25P(2)O(5). During the heat treatment process, two crystalline compounds were formed, NaMoO2PO4 and NaWO2PO4, respectively. Physico-chemical properties of the corresponding glasses and crystals were compared, as well as their Raman and P-31 MAS NMR spectra. Differential thermal analysis revealed crystallization peaks at 483 degrees C for the Mo-containing glass and at 624 degrees C for the W-containing glass; melting points of crystalline compounds were determined as 695 +/- 2 degrees C for NaMoO2PO4 and 858 +/- 2 degrees C for NaMoO2PO4. Sodium tungstate-phosphate glass has lower solubility in comparison with the sodium molybdatephosphate glass. The study of the crystallization mechanism showed a prevailing surface nucleation. P-31 MAS NMR spectra of the two glasses revealed the same shape and almost the same width, which reflects a similar local environment for P in these glasses. The position of the resonance for W-containing glass at a more negative chemical shift than the Mo-containing one is attributed to the different electrical field strength of W atoms than Mo atoms. P-31 MAS NMR spectra of crystals revealed two resonances at + 17 and -0.5 ppm for the Mo glass and at -0.1 and -1.9 ppm for the W glass, reflecting the presence of two different phosphorus short range environments, in agreement with their crystal structure. Raman spectra showed similarity in structural features for Mo and W glasses and their isomorphic compounds. Splitting of the dominant Raman bands in the crystal spectra reflects a distortion of MoO6 and WO6 octahedra. Raman spectra also suggested the breaking of Mo-O-Mo and WOW linkages during crystallization.

Název v anglickém jazyce

Crystallization of sodium molybdate-phosphate and tungstate-phosphate glasses

Popis výsledku anglicky

The glass to crystal transformation was studied for two glasses with composition 25Na(2)center dot O.50MoO(3)center dot 25P(2)O(6) and 25Na(2)O center dot 50WO(3)center dot 25P(2)O(5). During the heat treatment process, two crystalline compounds were formed, NaMoO2PO4 and NaWO2PO4, respectively. Physico-chemical properties of the corresponding glasses and crystals were compared, as well as their Raman and P-31 MAS NMR spectra. Differential thermal analysis revealed crystallization peaks at 483 degrees C for the Mo-containing glass and at 624 degrees C for the W-containing glass; melting points of crystalline compounds were determined as 695 +/- 2 degrees C for NaMoO2PO4 and 858 +/- 2 degrees C for NaMoO2PO4. Sodium tungstate-phosphate glass has lower solubility in comparison with the sodium molybdatephosphate glass. The study of the crystallization mechanism showed a prevailing surface nucleation. P-31 MAS NMR spectra of the two glasses revealed the same shape and almost the same width, which reflects a similar local environment for P in these glasses. The position of the resonance for W-containing glass at a more negative chemical shift than the Mo-containing one is attributed to the different electrical field strength of W atoms than Mo atoms. P-31 MAS NMR spectra of crystals revealed two resonances at + 17 and -0.5 ppm for the Mo glass and at -0.1 and -1.9 ppm for the W glass, reflecting the presence of two different phosphorus short range environments, in agreement with their crystal structure. Raman spectra showed similarity in structural features for Mo and W glasses and their isomorphic compounds. Splitting of the dominant Raman bands in the crystal spectra reflects a distortion of MoO6 and WO6 octahedra. Raman spectra also suggested the breaking of Mo-O-Mo and WOW linkages during crystallization.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10402 - Inorganic and nuclear chemistry

Projekt

<a href="/cs/project/GA18-01976S" target="_blank" >GA18-01976S: Nová perspektivní skla a skokeramické materiály na bázi fosforečnanů a borofosforečnanů</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Non-Crystalline Solids

ISSN

0022-3093

e-ISSN

—

Svazek periodika

500

Číslo periodika v rámci svazku

November

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

7

Strana od-do

42-48

Kód UT WoS článku

000447096600006

EID výsledku v databázi Scopus

2-s2.0-85048495041