Two Pyrophosphates with Large Birefringences and Second‐Harmonic Responses as Ultraviolet Nonlinear Optical Materials

Abstract

Two new pyrophosphates nonlinear optical (NLO) materials, Rb3PbBi(P2O7)2 (I) and Cs3PbBi(P2O7)2 (II), were successfully designed and synthesized. Both compounds exhibit large NLO effects and birefringences. Material I presents the scarce case of possessing the coexistence of large birefringence (0.031 at 1064 nm and 0.037 at 532 nm) and second harmonic generation (SHG) response (2.8× potassium dihydrogen phosphate (KDP)) in ultraviolet NLO phosphates and its SHG is the largest in the phase‐matching (PM) pyrophosphates. Both I and II have three‐dimensional (3D) crystal structures composed of corner‐shared RbO12 (CsO11), RbO10 (CsO10), BiO6, PbO7 (PbO6) and P2O7 groups, in which P2O7 and PbO7 (PbO6) units form an alveolate [PbPO]∞ skeleton frame. Theoretical calculations reveal that the P−O, Bi−O and Pb−O units are mainly responsible for the moderate birefringence and large SHG efficiency of I.

Synthesis and characterization of Cs2Zn4V4O15—a new vanadate in the Cs–Zn–V–O quaternary system

“…The crystal structure was analyzed and refined by direct methods and the SHELXTL system on Olex2 packages, respectively, and adopting the full matrix least squares method to refine all the positions of the atoms. [39][40][41][42][43] The missing symmetry elements of the structures were verified with PLATON, and no higher symmetries were found.…”

Synthesis, structures and properties of two new selenite optical materials: K2Zn3Se4O12 and K4Zn3V4Se2O19

“…The crystal structures were analyzed and refined by the direct methods and the SHELXTL system on Olex2 packages, respectively, and adopting the full matrix least squares method to refine all the positions of the atoms. [35][36][37][38][39] The missing symmetry elements of the structures were verified with PLATON and no higher symmetries were found. 40 Crystallographic data and structural refinements of the title compounds are summarized in Table 1.…”

Four New Sb‐based Orthophosphates: Cation Regulation to Investigate Diversified Structural Architecture

“…In addition, the structural flexibility can also be improved by introducing metal elements with strong covalency. Normally, phosphates contain only one kind of anion, such as LiHgPO 4 , Li 2 ABi(PO 4 ) 2 (A=K, Rb, and Cs) and KMg(H 2 O)PO 4 with isolated [PO 4 ] tetrahedral, [17–19] A 3 BBi(P 2 O 7 ) 2 (A=Rb, Cs; B=Pb, Ba) and M 4 Mg 4 (P 2 O 7 ) 3 (M=K, Rb) with isolated [P 2 O 7 ] dimers, [20–22] Ba 5 P 6 O 20 and AAl 3 P 6 O 20 (A=Rb, Cs) with isolated [P 3 O 10 ] trimers, [10b,23] isolated [P 3 O 9 ] rings for KMg(P 3 O 9 ) and BaNaP 3 O 9 , [24,25] [P 4 O 12 ] rings for Ca 2 (P 4 O 12 ) ⋅ 4H 2 O, [26] [P 6 O 18 ] rings for Cs 2 Mg 2 P 6 O 18 [27] as well as RbBa 2 (PO 3 ) 5 , β ‐Cd(PO 3 ) 2 with infinite [PO 3 ] ∞ chains [10a,28] . There are some exceptions for phosphates with mixed P−O anions, such as Pb 2 Cd 3 (PO 4 ) 2 (P 2 O 7 ), [29] Na 4 Mg 3 (PO 4 ) 2 P 2 O 7 , [30] and LiMg 3 (PO 4 )P 2 O 7 , etc [31]…”