First-principle calculations of MnO2 polymorphisms (rutile-type, CaCl2-type and pyrite-type) have been carried out with the full potential linearized augmented plane wave (FPLAPW) method. Through the calculations, we predict that the rutile-type MnO2 can transform to CaCl2-type at 5 GPa, and then transform to pyrite-type at 20 GPa. Furthermore, we summary the characteristic of several rutile-structure metal dioxide phases transformation under high pressure and conclude that the group Ⅳ element dioxides have similar sequence of the phase transition. In general, the pressure induced phase transformations of these group Ⅳ element dioxide take place at lower pressure with the increase of cations radii and decrease of the value of bulk moduli.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |