一类金属卤化物中孤对电子立体化学活性及其对双折射率的影响机制研究.

Birefringent compounds are widely used in engineering and researching fields like optical fiber. The electronic structures and birefringences of the post-transition metal halides PbX2 and BiX3(X=Cl, Br, I) were investigated by first-principles methods. The results show that the stereochemical activity of cations in PbX2 and BiX3(X=Cl, Br, I) decreases gradually from Cl to I. The stereochemical activity of the cation is determined by the energy level difference of the cation s orbital and the halogen p orbital. The greater the difference in energy levels, the weaker the degree of stereochemical activity of lone pair electrons. The cation p states nearby the Fermi level mainly determine the birefringence, which make the birefringence of PbX2 and BiX3(X=Cl, Br, I) gradually increase from CI to I. [ABSTRACT FROM AUTHOR]