I did the mechanical grinding of lanthanum oxide but I had an obstacle to determine the probable structure of this oxydeau. At the beginning I found at least three different structures. After grinding I found only the phase of the oxide of hexagonal structure?
Hello Samira,
At low temperatures, La2O3 has a hexagonal crystal structure. The La3+ metal atoms are surrounded by a 7 coordinate group of O2−atoms, the oxygen ions are in an octahedral shape around the metal atom and there is one oxygen ion above one of the octahedral faces. On the other hand, at high temperatures the Lanthanum oxide converts to a cubic crystal structure. The La3+ ion is surrounded by a 6 coordinate group of O2− ions.
Hope that helps and for more info you may have a look at the following literature.
Wyckoff, R. W.G. (1963). Crystal Structures: Inorganic Compounds RXn, RnMX2, RnMX3. New York: Interscience Publishers
Hello Samira,
At low temperatures, La2O3 has a hexagonal crystal structure. The La3+ metal atoms are surrounded by a 7 coordinate group of O2−atoms, the oxygen ions are in an octahedral shape around the metal atom and there is one oxygen ion above one of the octahedral faces. On the other hand, at high temperatures the Lanthanum oxide converts to a cubic crystal structure. The La3+ ion is surrounded by a 6 coordinate group of O2− ions.
Hope that helps and for more info you may have a look at the following literature.
Wyckoff, R. W.G. (1963). Crystal Structures: Inorganic Compounds RXn, RnMX2, RnMX3. New York: Interscience Publishers
Good evening Mr Mahendra Vidhura
thank you for your reply, I read that but for the sample I had done I have found lanthanum oxide stucture hexagonle and La (OH) 3 before grinding
Upon grinding, lanthanum oxide can react with air to form hydroxide, carbonates and hydroxocarbonates.
if you do XRD you will get practical idea and what phase change occured before and after mechanical grinding.
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