Hydrogen-Bond-Assisted Alignment of [MCu(SeO₃)₄Cl(H₂O)]^4– (M = Fe, Ga) Anionic Layers to Form Two Polar Oxychlorides: Pb₂MCu(SeO₃)₄Cl(H₂O)

Abstract

Two novel selenite oxychlorides Pb2MCu­(SeO3)4Cl­(H2O) (M = Fe, Ga) were hydrothermally synthesized and structurally characterized. They are isostructural and crystallize in the two-dimensional [MCu­(SeO3)4Cl­(H2O)]4– anionic layer structure mediated with hydrogen bonds and aligned between neighboring layers which assist in building the three-dimensional framework with a polar space group. Optical properties measurements revealed that the optical band gaps are 2.61 and 3.22 eV for Pb2FeCu­(SeO3)4Cl­(H2O) (1) and Pb2GaCu­(SeO3)4Cl­(H2O) (2) and the SHG responses are about 0.12 and 0.18 times that of KDP, respectively. Furthermore, 1 exhibits an interesting metamagnetic phenomenon under varied applied fields from around 1 to 4 T at 2 K, and 2 behaves with potential ferromagnetic ordering at low temperature.

Polar Bismuth Selenite Iodate Oxide BiSeIO6 with Three Types of Lone Pair Cations in One Structure

“…The selenium and iodine atoms both have the typical Se/I-O 3 pyramidal environments coordinated with three oxygen atoms along with the lone pair electrons at the top of the pyramids. The bond lengths of Se/I–O fall into the ranges of 1.779–1.799 and 1.724–1.758 Å for the Se/I(1) and Se/I(2) centers, respectively, which are consistent with the reported ones. − The average Se/I(1)–O distance is 1.786 Å, which is (Se: 0.64; I: 0.58, O: 1.22). The Se/I(1)–O distance is slightly larger than that of Se/I(2)–O because the occupancy ratio of iodine is larger on the Se/I(1) site than on the Se/I(2) site.…”

Analogous Chain Selenite Chlorides Ba2M(SeO3)2Cl2 (M = Cu2+, Ni2+, Co2+, Mn2+) and Pb2Cu(SeO3)2Cl2 with Tunable Spin S: Syntheses and Characterizations

“…Among them, the [SeO 3 ] 2– anion group with a stereochemically active lone electron pair can contribute to the design and synthesis of a large number of diverse novel compounds and provide a rich structural chemistry, particularly for the incorporation with halogen ions forming different anion groups by partial substitution of oxygen atoms. Experimentally, several magnetic selenide halides have been reported, such as Cu 3 Yb(SeO 3 ) 2 O 2 Cl 2 , Cu 3 Bi(SeO 3 ) 2 O 2 X (X = Br, Cl), KCu 5 O 2 (SeO 3 ) 2 Cl 3 , Pb 2 FeCu(SeO 3 ) 4 (H 2 O)Cl, CdCu 2 (SeO 3 ) 2 Cl 2 , , Sr 2 M(SeO 3 ) 2 Cl 2 (M = Cu, Ni, Co), − and Pb 2 Cu 10 O 4 (SeO 3 ) 4 Cl 7 …”

K4ZnV5O15Cl: A Congruent‐Melting Mid‐Infrared Nonlinear Optical Crystal Combined with Strong Second‐Harmonic Generation and High Laser‐Induced Damage Threshold

“…[14] Moreover, when multiple building units are concurrently arranged along a specific direction in the crystal structure, the local dipole moments will be constructively enhanced, thus a noncentrosymmetric or polar structure with large macroscopic polarization may be formed. [15] It is reported that vanadium exhibits a strong off-center distortion which is only slightly weaker than that of molybdenum in all the d 0 transition metal cations. [11b] However, there are few vanadates developed for practical NLO crystals at present.…”