Contribution of lone-pairs to birefringence affected by the Pb(ii) coordination environment: a DFT investigation

Abstract

Pb(II) cations have long been associated with lone-pairs which can help to enhance the optical anisotropic birefringence. In this paper, the contribution of lead cations to birefringence has been investigated using first-principles and real-space atom-cutting methods. The results show that the contribution of lead cations to birefringence is determined by the degree of stereochemical activity, which is affected by the coordination environment of lead cations.

Sn2PO4I: An Excellent Birefringent Material with Giant Optical Anisotropy in Non π‐Conjugated Phosphate

“…Furthermore, the d 0 or d 10 cations also play an important role in improving optical anisotropy of the crystals as exampled by KTiOPO 4 , [32] LiHgPO 4 [33] . Currently, the cations with stereochemical activity lone pairs could enhance birefringence based on theoretical calculation [24, 34] . Subsequently, we prepared two new crystals Sn 2 B 5 O 9 Cl and Sn 2 B 5 O 9 Br, [35, 36] and it experimentally demonstrated that [SnOX] (X=halogen) polyhedra can induce the large amplitude gain of birefringence.…”

α-, β-Pb4B2O7 and α-, β-Pb4B6O13: Polymorphism drives changes in structure and performance

“…In order to investigate the origin of the changes for the optical performances derived by the polymorphism, the electron localization function (ELF) analysis and realspace atom-cutting (RSAC) method [65][66][67][68] were employed to examine the contributions of the constituent functional groups for the two sets of polymorphs. As shown in the ELF diagrams ( Fig.…”

α‐SnF2: A UV Birefringent Material with Large Birefringence and Easy Crystal Growth

“…In recent years, the metal cations with stereochemical activity lone pair (SCALP), especially Sn II , [12, 13] are regarded as the excellent candidate for generating the obvious enhancement of birefringence after substituting alkaline‐earth metal cation in isostructural compounds [12a] . Previously, we successfully synthesized a new birefringent crystal, Sn 2 B 5 O 9 Cl, [14] whose birefringence is 16 times that of its isostructural compound Ba 2 B 5 O 9 Cl.…”