Controlling Nucleation and Crystal Growth of a Distinct Polyoxovanadate Cluster: An In Situ Energy Dispersive X‐ray Diffraction Study under Solvothermal Conditions |
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Authors: | Elena Antonova Beatrix Seidlhofer Jing Wang Michael Hinz Prof. Dr. Wolfgang Bensch |
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Affiliation: | University of Kiel, Institute of Inorganic Chemistry, Max‐Eyth‐Strasse 2, 24118 Kiel (Germany), Fax: (+49)?4318801520 |
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Abstract: | The formation of the antimonato polyoxovanadates [V14Sb8(C6H15N3)4O42(H2O)] ? 4H2O ( 1 ), (C6H17N3)2[V15Sb6(C6H15N3)2O42(H2O)] ? 2.5H2O ( 2 ), {C6H15N3}4[V16Sb4O42] 2H2O ( 3 ) (C6H15N3=1‐(2‐aminoethyl)piperazine, AEP) has been studied under solvothermal conditions by using in situ energy dispersive X‐ray diffraction (EDRXD). The syntheses were performed with an identical ratio for Sb2O3 and NH4VO3. If the reactions slurries are not stirred during the solvothermal reaction and by applying 70–75 % amine concentration, the products contain all three compounds, whereas 3 is observed at 80 %. Under stirring conditions, variation of the concentration of AEP led to crystallization of the three different compounds at distinct concentrations, that is, 1 is formed at 75 %, 1 and 2 between 75 and 80 % and 3 at 80 %. At an amine concentration of 77.5 %, first reflections of 2 occurred and at later stages, compound 1 started to crystallize. The sample with the lowest number of VIV species was formed at the lowest amine concentration, whereas crystallization of 3 required the highest concentration. The formation of the compounds occurred without crystalline intermediates and/or precursors. With increasing reaction temperature, the incubation time was significantly reduced. |
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Keywords: | crystal growth kinetics polyoxovanadates solvothermal synthesis X‐ray diffraction |
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