Aragonite-II and CaCO3-VII: New high-pressure, high-temperature polymorphs of CaCO3

Pavel N. Gavryushkin, Naira S. Martirosyan, Talgat M. Inerbaev, Zakhar I. Popov, Sergey V. Rashchenko, Anna Yu Likhacheva, Sergey S. Lobanov, Alexander F. Goncharov, Vitali B. Prakapenka, Konstantin D. Litasov

Результат исследования: Научные публикации в периодических изданияхстатья

22 Цитирования (Scopus)

Аннотация

The importance for the global carbon cycle, the P-T phase diagram of CaCO3 has been under extensive investigation since the invention of the high-pressure techniques. However, this study is far from being completed. In the present work, we show the existence of two new highpressure polymorphs of CaCO3. The crystal structure prediction performed here reveals a new polymorph corresponding to distorted aragonite structure and named aragonite-II. In situ diamond anvil cell experiments confirm the presence of aragonite-II at 35 GPa and allow identification of another high-pressure polymorph at 50 GPa, named CaCO3-VII. CaCO3-VII is a structural analogue of CaCO3-P21/c-l, predicted theoretically earlier. The P-T phase diagram obtained based on a quasi-harmonic approximation shows the stability field of CaCO3-VII and aragonite-II at 30-50 GPa and 0- 1200 K. Synthesized earlier in experiments on cold compression of calcite, CaCO3-VI was found to be metastable in the whole pressure-temperature range.

Язык оригиналаанглийский
Страницы (с-по)6291-6296
Число страниц6
ЖурналCrystal Growth and Design
Том17
Номер выпуска12
DOI
СостояниеОпубликовано - 1 янв 2017

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