A meticulously designed, polar, non-centrosymmetric lead borate chloride, Pb2 BO3 Cl, was synthesized using KBe2 BO3 F2 (KBBF) as a model. Single-crystal X-ray diffraction revealed that the structure of Pb2 BO3 Cl consists of cationic [Pb2 (BO3 )](+) honeycomb layers and Cl(-) anions. Powder second harmonic generation (SHG) measurements on graded polycrystalline Pb2 BO3 Cl indicated that the title compound is phase-matchable (type I) and exhibits a remarkably strong SHG response, which is approximately nine times stronger than that of potassium dihydrogen phosphate, and the largest efficiency observed in materials with structures similar to KBBF. Further characterization suggested that the compound melts congruently at high temperature and has a wide transparency window from the near-UV to the mid-IR region.
The solid-solution Zintl compounds with the mixed cations of Ca 2+ and Yb 2+ in the Ca 5−x Yb x Al 2 Sb 6 (1.0 ≤ x ≤ 5.0) system have been synthesized by high-temperature solid-state reactions. Two slightly different crystal structures of the Ba 5 Al 2 Bi 6 -type and Ca 5 Ga 2 Sb 6 -type phases have been characterized for seven compounds with 2.5 ≤ x ≤ 5.0 and three compounds with 1.0 ≤ x ≤ 2.0, respectively, by both powder and single-crystal X-ray diffraction analyses. The two title phases adopt the orthorhombic space group Pbam (Z = 2, oP26) with seven independent asymmetric atomic sites and share certain structural similarities, including infinite one-dimensional [Al 2 Sb 8 ] double chains and isolated space-filling Ca 2+ /Yb 2+ cations. Interestingly, we reveal the crystal-to-crystal solid-state structural transformation of the Yb-rich compound Ca 1.5 Yb 3.5 Al 2 Sb 6 from the Ba 5 Al 2 Bi 6 -type to the Ca 5 Ga 2 Sb 6 -type phase through the postannealing process, which can be rationalized as the phase transition from the kinetically more stable structure to the thermodynamically more stable crystal structure on the basis of theoretical calculations. Discrepancies of the local coordination geometries of the anionic [Al 2 Sb 8 ] units and the geometrical arrangements of structural building moieties in the two distinct phases provoke the different electrical properties of metallic and semiconducting conduction, respectively, for the Ba 5 Al 2 Bi 6 -type and Ca 5 Ga 2 Sb 6 -type phases. Density of states and crystal orbital Hamilton population analyses based on tight-binding linear muffin-tin orbital calculations prove that the band-gap opening in the Ca 5 Ga 2 Sb 6 -type phase should mainly be attributed to an extended bond distance of the bridging Sb−Sb in the [Al 2 Sb 8 ] unit. A series of thermoelectric (TE) property measurements indicates that the phase transition via the postannealing process eventually results in an enhancement of the TE performance of Yb-rich Ca 1.5 Yb 3.5 Al 2 Sb 6 .
A highly thermostable carbonatoperoxovanadate, Cs3VO(O2)2CO3, exhibits a remarkably strong SHG response of approximately 23.0 times that of KDP, which is the largest among those of the reported NLO carbonate materials.
Reported are the synthesis and the structural characterization of two members of a new homologous series of polar intermetallic compounds, which exist only with mixed alkaline-earth and rare-earth metal cations. Crystals of (Eu(1-x)Ca(x))(4)In(3)Ge(4) (0.35(1)
A meticulously designed, polar, non‐centrosymmetric lead borate chloride, Pb2BO3Cl, was synthesized using KBe2BO3F2 (KBBF) as a model. Single‐crystal X‐ray diffraction revealed that the structure of Pb2BO3Cl consists of cationic [Pb2(BO3)]+ honeycomb layers and Cl− anions. Powder second harmonic generation (SHG) measurements on graded polycrystalline Pb2BO3Cl indicated that the title compound is phase‐matchable (type I) and exhibits a remarkably strong SHG response, which is approximately nine times stronger than that of potassium dihydrogen phosphate, and the largest efficiency observed in materials with structures similar to KBBF. Further characterization suggested that the compound melts congruently at high temperature and has a wide transparency window from the near‐UV to the mid‐IR region.
A nonlinear optical (NLO) carbonatoperoxovanadate, Rb VO(O ) CO , was synthesized through a simple solution-evaporation method in phase-pure form. Single-crystal X-ray diffraction revealed that the structure of Rb VO(O ) CO consists of important noncentrosymmetric (NCS) chromophores, that is, π-delocalized (CO ) groups, a second-order Jahn-Teller (SOJT) distortive V cation, and π-localized distorted O groups, as well as charge-balancing polarizable Rb ions. The powder second-harmonic generation (SHG) measurements indicated that Rb VO(O ) CO is phase-matchable (Type I) and exhibits a remarkably strong SHG response circa 21.0 times that of potassium dihydrogen phosphate (KDP), which is the largest efficiency observed among carbonate NLO materials. First-principles calculation analysis suggests that the extremely large SHG response of Rb VO(O ) CO is attributed to the synergistic effect of the cooperation of all the constituting NCS chromophores.
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