Thermal Transformations of the Composition and Structure of Hexagonal Molybdenum Oxide
Научная публикация
| Общая информация |
Язык:
Английский,
Жанр:
Статья (Full article),
Статус опубликования:
Опубликована,
Оригинальность:
Переводная
|
| Журнал |
Journal of Structural Chemistry
ISSN: 0022-4766
, E-ISSN: 1573-8779
|
| Вых. Данные |
Год: 2015,
Том: 56,
Номер: 2,
Страницы: 289-296
Страниц
: 8
DOI:
10.1134/S0022476615020122
|
| Ключевые слова |
crystal texture, hygroscopic crystals, metastable phase, molybdenum oxide, structural water |
| Авторы |
Troitskaia I.B.
1
,
Gavrilova T.A.
1
,
Zubareva A.P.
2
,
Troitskii D.Yu.
2
,
Gromilov S.A.
2,3
|
| Организации |
| 1 |
Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
|
| 2 |
Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
|
| 3 |
Novosibirsk National Research State University, Russia
|
|
Thermal transformations of the crystal structure and composition of the h-MoO3 metastable phase with a transition to the α-MoO3 stable modification are investigated. The study is performed using submicron phase-pure crystals exhibiting stability during their long storage in the air. By powder XRD, SEM, TGA, CHN, LMS, Raman and IR spectroscopy it is found: the composition of the deposited crystals is expressed by the general formula MoO3·0.26H2O; the impurity cationic composition consists of 1.8 wt.% of ammonia groups and a sum of 15 elements detected at a level of 10−4 wt.%. Thermal treatment of the crystals to T = 350 °C in the air results in the removal of adsorbed and structural water, OH−, and NH 4 + groups with retaining the h-phase of hygroscopic MoO3·0.08H2O. The h-MoO3·0.08H2O crystals obtained show instability during the storage and transform into the α-MoO3 stable modification. At T = 380 °C the h → α phase transition occurs with the removal of coordinated water and texture transformations resulting in the formation of α-MoO3 hygroscopic crystals that at T = 650 °C acquire the platelet shape characteristic of the α-phase.