Solvent-free ageing reactions of rare earth element oxides: from geomimetic synthesis of new metal–organic materials towards a simple, environmentally friendly separation of scandium

Solvent-free accelerated ageing converts metal oxides into metal oxalate frameworks, enabling simple separation of scandium from other rare earth elements.

STRUCTURES AND ELECTRONIC PROPERTIES OF FOUR CRYSTAL GeO2 AND TWO RARE-EARTH ELEMENT OXIDES La2O3 AND CeO2: FIRST PRINCIPLES CALCULATION

This paper presents a first principles calculation of the structure and electronic properties of four crystal GeO2 structures and two rare-earth element oxides CeO2 and La2O3 . A GGA was used to optimize structures and calculate band structure and density of states (DOS). It is found that La2O3 has the largest band gap (4.19 eV) among all the six structures, which also means it is the best insulator among them. When it comes to four crystal GeO2 structures, which were calculated to make a comparison with two insulators CeO2 and La2O3 , we found the q- GeO2 and b- GeO2 are more likely to work as the dielectrics used in MOS devices than the other two crystalline forms. Three of the four GeO2 forms have larger band gap than that of CeO2 (2.09 eV), which indicates CeO2 is not a wise choice when deposited directly on the surface of Ge substrate.