On the thermal decomposition of zinc hydroxidenitrate, Zn5(OH)8(NO3)2⋅2H2O

Moezzi, A; Lee, PS; McDonagh, AM; Cortie, MB

On the thermal decomposition of zinc hydroxidenitrate, Zn5(OH)8(NO3)2⋅2H2O

Moezzi, A Lee, PS McDonagh, AM Cortie, MB

Permalink

Publisher:: Elsevier BV
Publication Type:: Journal Article
Citation:: Journal of Solid State Chemistry, 2020, 286
Issue Date:: 2020-06-01

Closed Access

	Filename	Description	Size
	1-s2.0-S0022459620301419-main.pdf	Published version	1.9 MB	Adobe PDF	View/Open

Copyright Clearance Process

Recently Added
In Progress
Closed Access

This item is closed access and not available.

Full metadata record

Field	Value	Language
dc.contributor.author	Moezzi, A
dc.contributor.author	Lee, PS
dc.contributor.author	McDonagh, AM
dc.contributor.author	Cortie, MB
dc.date.accessioned	2021-01-11T03:40:04Z
dc.date.available	2021-01-11T03:40:04Z
dc.date.issued	2020-06-01
dc.identifier.citation	Journal of Solid State Chemistry, 2020, 286
dc.identifier.issn	0022-4596
dc.identifier.issn	1095-726X
dc.identifier.uri	http://hdl.handle.net/10453/145287
dc.description.abstract	© 2020 Elsevier Inc. The layered basic hydroxide Zn5(OH)8(NO3)2⋅2H2O can be thermally decomposed to ZnO via a series of intermediary compounds. Application of in situ X-ray diffraction to dry powder samples reveals three reactions: formation of anhydrous Zn5(OH)8(NO3)2, then de-hydroxylation to Zn3(OH)4(NO3)2 and, finally, decomposition of the latter to ZnO. In contrast, thermal analysis and mass spectroscopy of the evolved volatiles suggests that four reactions take place. Whereas de-hydroxylation reactions only produce H2O, there is also a distinctive pulse of NOx and O2 at the end of the sequence of reactions. The evidence points to the formation of an intermediate, poorly crystalline phase with a stoichiometry of [Zn(OH)2-x]⋅[NO3]x (1 < x < 2) during the final stages of the reaction sequence. Isothermal calcination of Zn5(OH)8(NO3)2⋅2H2O at 120 °C showed that the anhydrous Zn5(OH)8(NO3)2 compound is unstable, rehydrating very rapidly on cooling or decomposing within 6 or 7 h at 120 °C to Zn3(OH)4(NO3)2 (at a rate of 1.33 × 10-4 s-1). Zn3(OH)4(NO3)2 itself decomposes slowly to ZnO at 120 °C, but the process is slower (5.33 × 10-6 s-1) and there was still considerable Zn3(OH)4(NO3)2 present even after 140 h. The mixtures of Zn3(OH)4(NO3)2 and ZnO prepared by calcination are unstable under ambient conditions and react with moisture to reform Zn5(OH)8(NO3)2⋅2H2O.
dc.language	en
dc.publisher	Elsevier BV
dc.relation.ispartof	Journal of Solid State Chemistry
dc.relation.isbasedon	10.1016/j.jssc.2020.121311
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject	0302 Inorganic Chemistry, 0303 Macromolecular and Materials Chemistry, 0306 Physical Chemistry (incl. Structural)
dc.subject.classification	Inorganic & Nuclear Chemistry
dc.title	On the thermal decomposition of zinc hydroxidenitrate, Zn5(OH)8(NO3)2⋅2H2O
dc.type	Journal Article
utslib.citation.volume	286
utslib.for	0302 Inorganic Chemistry
utslib.for	0303 Macromolecular and Materials Chemistry
utslib.for	0306 Physical Chemistry (incl. Structural)
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - CCET - Centre for Clean Energy Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
pubs.organisational-group	/University of Technology Sydney
utslib.copyright.status	closed_access	*
pubs.consider-herdc	false
dc.date.updated	2021-01-11T03:39:35Z
pubs.publication-status	Published
pubs.volume	286

Abstract:

© 2020 Elsevier Inc. The layered basic hydroxide Zn5(OH)8(NO3)2⋅2H2O can be thermally decomposed to ZnO via a series of intermediary compounds. Application of in situ X-ray diffraction to dry powder samples reveals three reactions: formation of anhydrous Zn5(OH)8(NO3)2, then de-hydroxylation to Zn3(OH)4(NO3)2 and, finally, decomposition of the latter to ZnO. In contrast, thermal analysis and mass spectroscopy of the evolved volatiles suggests that four reactions take place. Whereas de-hydroxylation reactions only produce H2O, there is also a distinctive pulse of NOx and O2 at the end of the sequence of reactions. The evidence points to the formation of an intermediate, poorly crystalline phase with a stoichiometry of [Zn(OH)2-x]⋅[NO3]x (1 < x < 2) during the final stages of the reaction sequence. Isothermal calcination of Zn5(OH)8(NO3)2⋅2H2O at 120 °C showed that the anhydrous Zn5(OH)8(NO3)2 compound is unstable, rehydrating very rapidly on cooling or decomposing within 6 or 7 h at 120 °C to Zn3(OH)4(NO3)2 (at a rate of 1.33 × 10-4 s-1). Zn3(OH)4(NO3)2 itself decomposes slowly to ZnO at 120 °C, but the process is slower (5.33 × 10-6 s-1) and there was still considerable Zn3(OH)4(NO3)2 present even after 140 h. The mixtures of Zn3(OH)4(NO3)2 and ZnO prepared by calcination are unstable under ambient conditions and react with moisture to reform Zn5(OH)8(NO3)2⋅2H2O.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/145287