Thermal Transformations of α-H6P2Mo 18O62·nH2O Heteropolyacid
Научная публикация
| Общее |
Язык:
Английский,
Жанр:
Статья (Full article),
Статус опубликования:
Опубликована,
Оригинальность:
Переводная
|
| Журнал |
Russian Chemical Bulletin
ISSN: 1066-5285
, E-ISSN: 1573-9171
|
| Вых. Данные |
Год: 2003,
Том: 52,
Номер: 1,
Страницы: 103-108
Страниц
: 6
DOI:
10.1023/A:1022492114284
|
| Ключевые слова |
31P NMR spectroscopy, Heteropolyacid, Thermogravimetric analysis, Thermolysis |
| Авторы |
Maksimovskaya R.I.
1
,
Maksimov G.M.
1
,
Litvak G.S.
1
|
| Организации |
| 1 |
Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 5 prosp. Akad. Lavrent'eva, 630090 Novosibirsk, Russian Federation
|
|
According to the 31P NMR spectroscopy, heteropolyacid (HPA) H6P2Mo18O62·nH2O (P2Mo18), α-isomer of the Dawson structure, transforms upon heating above 80 °C partially (up to 30%) to γ-isomer, in which both polar groups Mo3O13 of the heteropolyanion are turned by 60° around the N3 axis, and partially to β-isomer in which only one group is turned. The β- and γ-isomers of P2Mo18 have been found for the first time. Their transformation into the α-isomer occurs upon rehydration in one week in air and in 1 h in an aqueous solution. HPA P2Mo18 decomposes on heating up to 350 °C to HPA H3PMo12O40 (PMo12) and a previously unknown phase of the HPMo6I21 composition, which in its turn decomposes at ∼375 °C to molybdenyl phosphates and IiI3. The PMo12 decomposition occurs via two routes to form the same products at temperatures of ∼400 and 450 °C with corresponding exotherms of IiI3 crystallization.