Kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates.
The room-temperature crystallization of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)], an organically templated zinc phosphate containing [Zn(2)(HPO(4))(2)(H(2)PO(4))(4)](4)(-) molecular anions, and its transformation to compounds containing either one- or two-dimensional inorganic components, [C(6)N(2)...
| Main Authors: | , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
2004
|
| _version_ | 1797056643394961408 |
|---|---|
| author | Norquist, A O'Hare, D |
| author_facet | Norquist, A O'Hare, D |
| author_sort | Norquist, A |
| collection | OXFORD |
| description | The room-temperature crystallization of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)], an organically templated zinc phosphate containing [Zn(2)(HPO(4))(2)(H(2)PO(4))(4)](4)(-) molecular anions, and its transformation to compounds containing either one- or two-dimensional inorganic components, [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)], [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)], or [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)], under hydrothermal conditions were studied in-situ using energy-dispersive X-ray diffraction. The ability to collect data during reactions in a large volume ( approximately 23 mL) Teflon-lined autoclave under real laboratory conditions has allowed for the elucidation of kinetic and mechanistic information. Kinetic data have been determined by monitoring changes in the integrated peak intensities of Bragg reflections and have been modeled using the Avrami-Erofe'ev expression. The crystallization of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)] is a diffusion-controlled process, while nucleation is increasingly more important in determining the overall rate of the formation of [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)], [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)], and [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)]. The transformation of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)] to [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)] and [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)] occurs via a dissolution-reprecipitation mechanism, while the transformation to [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)] may be the first observation of a direct topochemical conversion of one organically templated solid to another under hydrothermal conditions. |
| first_indexed | 2024-03-06T19:25:30Z |
| format | Journal article |
| id | oxford-uuid:1b8f7af1-8260-4b69-887a-34425db8855c |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:25:30Z |
| publishDate | 2004 |
| record_format | dspace |
| spelling | oxford-uuid:1b8f7af1-8260-4b69-887a-34425db8855c2022-03-26T11:01:05ZKinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:1b8f7af1-8260-4b69-887a-34425db8855cEnglishSymplectic Elements at Oxford2004Norquist, AO'Hare, DThe room-temperature crystallization of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)], an organically templated zinc phosphate containing [Zn(2)(HPO(4))(2)(H(2)PO(4))(4)](4)(-) molecular anions, and its transformation to compounds containing either one- or two-dimensional inorganic components, [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)], [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)], or [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)], under hydrothermal conditions were studied in-situ using energy-dispersive X-ray diffraction. The ability to collect data during reactions in a large volume ( approximately 23 mL) Teflon-lined autoclave under real laboratory conditions has allowed for the elucidation of kinetic and mechanistic information. Kinetic data have been determined by monitoring changes in the integrated peak intensities of Bragg reflections and have been modeled using the Avrami-Erofe'ev expression. The crystallization of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)] is a diffusion-controlled process, while nucleation is increasingly more important in determining the overall rate of the formation of [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)], [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)], and [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)]. The transformation of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)] to [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)] and [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)] occurs via a dissolution-reprecipitation mechanism, while the transformation to [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)] may be the first observation of a direct topochemical conversion of one organically templated solid to another under hydrothermal conditions. |
| spellingShingle | Norquist, A O'Hare, D Kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates. |
| title | Kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates. |
| title_full | Kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates. |
| title_fullStr | Kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates. |
| title_full_unstemmed | Kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates. |
| title_short | Kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates. |
| title_sort | kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates |
| work_keys_str_mv | AT norquista kineticandmechanisticinvestigationsofhydrothermaltransformationsinzincphosphates AT ohared kineticandmechanisticinvestigationsofhydrothermaltransformationsinzincphosphates |