Structure
At low temperatures, La2O3 has an A-M2O3 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 C-M2O3 cubic crystal structure. The La3+ ion is surrounded by a 6 coordinate group of O2- ions.
Read more about this topic: Lanthanum(III) Oxide
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