염화이트륨과 옥살산의 반응성 결정화에 의해 생성된 이트륨옥살레이트의 열분해에 대한 연구를 수행하였다. 이트륨옥살레이트 결정은 monoclinic 결정계에 속하며 약 3개의 결정수를 포함하고 있었으며 이 결정수는 이트륨옥살레이트의 열분해 반응에 앞서 탈수되는 것을 알 수 있었다. 결정수의 탈수는 이트륨옥살레이트의 분자결합 및 결정구조에는 변화를 주지 않았으나 결정입자의 크기와 모양에는 많은 영향을 미쳤다. 이트륨옥살레이트 열분해 반응은 366℃ 이상의 온도에서 시작되었다. 366-465℃ 사이의 온도에서는 이트륨옥살레이트가 열분해되었으나 안정적인 결정성 생성물을 형성하지 못하였다. 그러나 500℃ 이상의 온도에서는 열분해에 의해 입방정계의 산화이트륨이 생성되었다. Hyper-Chem을 이용하여 반응성 결정화에 의해 합성된 이트륨옥살레이트는 3차원적 분자구조를 가지며 이의 열분해에 의해 생성되는 산화이트륨도 3차원적 분자구조를 가진다는 것을 예측하였다. 질소 분위기에서의 이트륨옥살레이트 열분해 실험에서도 동일한 결과가 나타났다.

Study on thermal decomposition of yttrium oxalate produced by reaction crystallization of yttrium chloride and oxalic acid was carried out. The yttrium oxalate having three crystal waters belonged to monoclinic crystal system and the crystal waters of yttrium oxalate were dehydrated before the yttrium oxalate was thermally decomposed. The dehydration of crystal water in yttrium oxalate did not changed the molecular bonding and crystal structure of yttrium oxalate but gave significant influence on shape and size of yttrium oxalate crystal. Thermal decomposition of yttrium oxalate occured above 366℃. Between 366-465℃ the yttrium oxalate was thermally decomposed and it resulted in a non-stable and non-crystalline product. Above 500℃, however, yttrium oxide having cubic crystal system was produced by the thermal deccomposition. By using Hyper-Chem it was predicted that the yttrium oxalate synthesized by the reaction crystallization and the yttrium oxide produced by the thermal decomposition had three dimensional molecular structures, which were preferred thermodynamically. The results of thermal decomposition of yttrium oxalate under nitrogen gas were same with those under air.

Yttrium Oxalate Yttrium Oxide Reaction Precipitation Thermal Decomposition Crystal Structure

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