Kaitong Liu,Jian Han,Fuming Li,Congcong Jin,Zhihua Yang,Miriding Mutailipu,Shilie Pan
A case of hydrous borate with the formula of Ba 2 B 13 O 19 (OH) 5 ·5H 2 O was synthesized by the traditional hydrothermal method . It crystallizes in the chiral P 1 space group and has a unique two-dimensional 2 [B 13 O 19 (OH) 5 ] ∞ layer that is constructed by the hydrogen involved [B 13 O 22 (OH) 5 ] fundamental building blocks (FBBs). The Ba atoms and H 2 O molecules are filled in the three-dimensional pore constructed by the 2 [B 13 O 19 (OH) 5 ] ∞ layer. Interestingly, Ba 2 B 13 O 19 (OH) 5 ·5H 2 O is the first case of hydrous borates that has the above rare [B 13 O 22 (OH) 5 ] FBB and 2 [B 13 O 19 (OH) 5 ] ∞ layer, which enriching the structural chemistry of borate system. The diffuse reflection spectrum result shows that the ultraviolet (UV) cutoff edge of Ba 2 B 13 O 19 (OH) 5 ·5H 2 O is below 200 nm. Its second harmonic generation (SHG) response is approximately 1.0 times that of potassium dihydrogen phosphate at the 1064 nm fundamental wavelength and it is also phase-matchable. Both results indicate that the title compound is a nonlinear optical crystal for UV spectral region. Theoretical simulation calculation shows that the occupied VE states are mainly contributed by the O-2p orbitals, and therefore [B 13 O 22 (OH) 5 ] groups are the main sources of SHG effects.
Juhe Liu,Yuwei Chen,Mengran Sun,Wenhao Liu,Xianghe Meng,Jiyong Yao
A new complex rare earth borate K7PbLu2B15O30 was prepared by the spontaneous crystallization method. K7PbLu2B15O30 is crystallized in the chiral trigonal space group R32 with cell parameters a = b = 13.0893(3) Å, c = 15.2379(6) Å, α = β = 90°, γ = 120°, and Z = 3. The basic structure of the crystal can be seen as composed of B5O10 groups and LuO6 polyhedra sharing oxygen atoms, while K+ and Pb2+ fill the space to balance the charge. The UV transmission cut-off edge of K7PbLu2B15O30 was less than 300 nm, and the powder SHG response was roughly 1.1 times that of KDP. Furthermore, a first-principles analysis was performed to see more about the relationship between the crystal structure and optical characteristics.
Wen Xin,Lin Chensheng,Luo Min,Fan Huixin,Chen Kaichuang,Ye Ning
[PO 4 ] 3− possesses small microscopic second-order susceptibility and polarizability anisotropy, which inherently result in weak second-harmonic generation (SHG) and small birefringence. Herein, a new noncentrosymmetric phosphate, [C(NH 2 ) 3 ] 3 PO 4 ·2H 2 O, was successfully designed and synthesized by a solution evaporation method. [C(NH 2 ) 3 ] 3 PO 4 ·2H 2 O without metal ions is composed of planar conjugated guanidine cations and PO 4 tetrahedrons, which are connected by hydrogen bonds, forming a three-dimensional network. Physical property measurements indicate that the title compound displays an SHG response of 1.5 × KH 2 PO 4 (KDP) and a larger birefringence (0.055@546.1 nm) compared with most reported ultraviolet nonlinear optical phosphates. Furthermore, first-principles calculations reveal that the π-conjugated planar [C(NH 2 ) 3 ] + cations and [PO 4 ] 3− groups are responsible for its excellent linear and NLO properties.