LiKSO4的无公度相

本文用多晶X射线衍射配合差热分析的方法研究了LiKSO₄室温以上的相变。发现当温度在熔点以下到675℃之间,晶体结沟与α-K₂SO₄的高温相同构,α相最可能的空间群为P6₃/mmc.在T_i=675℃以下出现调制结构,类似K₂WO₄,K₂MoO₄等的无公度相;参数κ的值由0.492(640℃)而随温度变化。在470℃出现整合相变κ=0.500,整合后的结构为室温相的超点阵。然后在439℃转变为室温相(空间群为P6₃)。 关键词：

THE INCOMMENSURATE PHASE OF LiKSO4

The phase transitions of LiKSO₄ have been investigated by means of X-ray powder diffraction and thermal analysis above room temperature. It is established that the crystal structure of LiKSO₄ between the melting point and 675℃ is isostructural with the high temperature phase of α-K₂SO₄ and its space group is probably P6₃/mmc. Cooling below T_i=675℃ , there appears an incommensurately modulated structure analogous to the incommensurate phase in K₂WO₄, K₂MoO₄, etc. The parameter κ changes with temperature from 0.492(640℃ ) to 0.500(470℃ ). At 470℃ , I→C phase transition (lock-in) takes place, after which the crystal structure becomes the superstructure lattice of the room temperature phase. At 439℃ the superstructure disappears yielding to the room temperature phase (P6₃).