Syntheses, Crystal Structures, Magnetic and Luminescent Properties of two Classes of Molybdenum(VI) Rich Quaternary Lanthanide Selenites

Ln2 F2 (OH2 )(MoO3 )2 (SeO3 )2 : Promising Multifunctional Nonlinear Optical Materials Created by Partial Fluorination Strategy under Corrosion Resistant Supercritical Reactions

It has historically been exceedingly challenging to create physically and chemically stable lanthanide compounds with strong second harmonic generation (SHG) due to their strong preference to central symmetry. In this work, five new non-centrosymmetric lanthanide selenites, namely, Ln2 F2 (OH2 )(MoO3 )2 (SeO3 )2 (Ln = Sm, Eu, Gd, Tb and Dy), are achieved by partial fluorination of the lanthanide oxygen polyhedron. An HF corrosion resistant supercritical hydrothermal method is developed, which is a facile and universal method for HF corrosion and high-temperature high-pressure environment. The title compounds displayed a novel 3D framework composed of 1D molybdenum selenite chains bridged by Ln2 F2 O12 (OH2 ) dimers. Their powder SHG responses showed a large difference, ranging from 1.0 to 9.0 × KH2 PO4 (KDP) at 1064 nm. The half-filled Gd compound exhibited very strong SHG efficiency of up to 1.2 × KTP (KTiOPO4 ) at 2050 nm. Compounds Tb and Gd are the first lanthanide selenites with SHG intensity reaching KTP level, which is very rare in this system. Furthermore, these compounds can also possess excellent physicochemical stability and strong luminescence emission, indicating that they are promising multifunctional nonlinear optical materials. This work offered an effective way for design and synthesis of multifunctional and high-performant nonlinear optical materials.

Cd4REO(BO3)3 (RE = Sm, Eu, Tb): Three new cadmium-rare earth-oxyborates with both good NLO and luminescent properties

Three nonlinear optical materials Cd4REO(BO3)3(RE = Sm, Eu, Tb) have been synthesized through high-temperature solid-state reactions. In their crystal structures, Cd(1)O8 and Cd(2)O6 polyhedra are interconnected via sharing edges and...

Structural Complexity and Magnetic Orderings in a Large Family of 3d-4f Heterobimetallic Sulfates

The synthesis of a large family of heterobimetallic lanthanide copper sulfates was realized via stoichiometric hydrothermal reactions among Ln₂O₃, CuO, and H₂SO₄, giving rise to four distinct phases, namely Ln₂Cu(SO₄)₂(OH)₄ (Ln = Sm-Ho) (LnCuSO₄-1), Ln₄Cu(SO₄)₂(OH)₁₀ (Ln = Tm-Lu) (LnCuSO₄-2), LnCu(SO₄)(OH)₃ (Ln = Nd-Gd, except Pm) (LnCuSO₄-3), and LnCu(SO₄)(OH)₃ (Ln = Dy-Lu) (LnCuSO₄-4), with completely different topologies. The passage from LnCuSO₄-1 and LnCuSO₄-3 to LnCuSO₄-2 and LnCuSO₄-4 across the 4f series, respectively, can be ascribed to the effect of lanthanide contraction, which progressively induces shrinking of the Ln-O distance, reduction in the Ln coordination number, and eventually structural transitions. The incorporation of identical 3d-4f metal ions into different spin-lattices, in conjunction with substitution of diverse Ln³⁺ cations within the same spin-lattice, gives rise to tunable magnetic properties varying from ferromagnetic ordering in GdCuSO₄-3 and HoCuSO₄-4 to antiferromagnetic ordering in YbCuSO₄-4, and to paramagnetic correlations found in GdCuSO₄-1 and YbCuSO₄-2.

Synthesis and structural characterization of BaSr2Ge3O9

BaSr2Ge3O9 was prepared by high-temperature solid-state synthesis at 1100°C in a platinum crucible from barium carbonate, strontium carbonate, and germanium(IV) oxide. The compound crystallizes in the triclinic space group P1̅ (no. 2) isotypically to walstromite BaCa2Si3O9. The structure was refined from single-crystal X-ray diffraction data: a=7.104(5), b=10.060(7), c=7.099(5) Å, α=83.0(2), β=77.0(2), γ=70.2(2)°, V=464.3(6) Å3, R1=0.0230, and wR2=0.0602 for all data. BaSr2Ge3O9 is characterized by three-membered rings of germanate tetrahedra. There are three crystallographically different Ge sites (Ge1, Ge2, and Ge3) in each [Ge3O9]6− ring. The rings occur in layers with the apices of alternating rings pointing in opposite directions. The Sr2+ and Ba2+ ions are located in between. The Sr1 cation is eight-fold coordinated, while Sr2 is octahedrally surrounded by oxide anions, and the Ba cation again eight-fold coordinated.

Synthesis and structural characterization of Ca12Ge17B8O58

Ca12Ge17B8O58 was prepared by high-temperature solid state synthesis at 1100°C in a platinum crucible from calcium carbonate, boric acid, and germanium(IV) oxide. The compound crystallizes in the tetragonal crystal system in the space group P4̅ (No. 81) isotypically to Cd12Ge17B8O58. The structure was refined from single-crystal X-ray diffraction data: a = 15.053(8), c = 4.723(2) Å, V = 1070.2(2) Å3, R1 = 0.0151, and wR2 = 0.0339 for all data. The crystal structure of Ca12Ge17B8O58 consists of [Ge4O12] n chains composed of GeO4 tetrahedra and GeO6 octahedra. The chains are interconnected into a [Ge4O10.5] n network via corner sharing. By additional [Ge(B2O7)4]28– clusters, these units are connected to a three-dimensional [Ge17B8O58]24– framework. The open structure forms three types of tunnels with five-, six-, and seven-membered rings (MRs) along the c axis, where the Ca2+ are located.

Ln2Ga[B3O6(OH)]2[B7O9(OH)2](CH3CO2)2 (Ln = Y, Sm, Eu, Gd, Dy): A Series of Lanthanide Galloborates Decorated by Acetate Anions

The first examples of mixed-anion lanthanide galloborates, namely, Ln2Ga[B3O6(OH)]2[B7O9(OH)2](CH3CO2)2 [Ln = Y (1), Sm (2), Eu (3), Gd (4), Dy (5)], have been obtained through hydrothermal synthesis. The title compounds are isomorphic and belong to monoclinic space group C2/c (No. 15). Their structures possess [B7O13(OH)2] borate layers further bridged with [B3O7] clusters to give a three-dimensional (3D) borate framework displaying two types of rhombus-like B14O14 14-membered-ring (14-MR) channels along the b axis. The Ga(3+) ions are octahedrally coordinated and located at one end of the B14O14 14-MR channels, forming small tunnels of B7Ga 8-MRs, which are filled by the Ln(III) ions. The Ln ions and Ga cations are further held together by bridging acetate anions. It is worth noting that in these compounds there are two different types of borate clusters and two types of anions that are uncommon in the borates reported. Luminescent studies revealed the characteristic emission bands of Ln ions for compounds 2-5, and the luminescent lifetimes are 3.6, 0.86, and 3.05 ns for compounds 2, 3, and 5, respectively. Magnetic measurements suggest that there are antiferromagnetic interactions between magnetic centers for compounds 2-5.

Effects of Te(IV) Oxo-Anion Incorporation into Thorium Molybdates and Tungstates

The exploration of phase formation in the Th-Mo/W-Te systems has resulted in four mixed oxo-anion compounds from high-temperature solid-state reactions: ThWTe2O9, Th(WO4)(TeO3), ThMoTe2O9, and Th2(MoO4)(TeO3)3. All four compounds contain edge-sharing thorium polyhedra linked by MoO4/WO6 and different tellurium oxo-groups to form three-dimensional frameworks. In ThWTe2O9, each helical Th based chain is connected by four tungstotellurite clusters resulting in a building fragment which has a cross-section of four-leafed clovers. The structure of Th(WO4)(TeO3) exhibits a multilayer-sandwich framework composed of thorium tellurite layers with tungsten chains in between. In the case of the molybdate family, ThMoTe2O9 and Th2(MoO4)(TeO3)3 are built from puckered Th-Te sheets which are further interconnected by MoO4 tetrahedral linkers. The DSC-TG technique was performed to gain insight into the thermal behavior of the synthesized compounds. Raman spectra of as-prepared phases were obtained and analyzed for signature peaks.

Synthesis and characterization of PbBaGeO4

PbBaGeO4was prepared by high-temperature solid-state synthesis at 900 °C in a platinum crucible from lead(II) oxide, barium carbonate, and germanium(IV) oxide. This compound crystallizes with the BaNdGaO4structure type in the orthorhombic space groupP212121(no. 19). The structure was refined from single-crystal X-ray diffraction data:a= 1021.6(2),b= 763.4(2),c= 618.1(2) pm,V= 482.1(2) Å3, and residuals ofR1= 0.0373 andwR2= 0.0730 for all data. Next to structural data, Raman spectroscopic data of PbBaGeO4are reported.

Theoretical exploration to the cation effect on the second-order nonlinear optical properties of Strandberg-type polyoxometalates

The combination of cations with octahedral coordinated d0 transition metal ions has been proved to be an effective way for designing new polar materials. So we investigate the second-order nonlinear optical (NLO) properties of Strandberg-type polyoxometalates (POMs) with alkali metal cations M 6 Mo 5 X 2 O 23 ( M = K +, Rb +, Cs +; X = P , As ) and M 4 M o5 X 2 O 21 ( M = K +, Rb +, Cs +; X = S , Se , Te ) by density functional theory (DFT) method. The calculated results show that this kind of Strandberg-type POMs possesses remarkably large molecular second-order NLO polarizability, especially for the Cs 6 Mo 5 P 2 O 23 (system Ic), which has a computed β0 value of 12526 a.u. and might be an excellent second-order NLO material. Moreover, the cations have important impact on the second-order NLO polarizabilities. Therefore, a careful choice of appropriate cations may allow the control of the second-order NLO response on these Strandberg-type POMs, which may provide a new route to design efficient NLO materials.

A novel cobalt (I) coordination polymer with mixed thiocyanate and quinoline ligands: crystal structure, magnetism and luminescent properties

A new Co(I) one-dimensional coordination polymer [Co(SCN)(ql)]n (ql=quinoline) (1) has been synthesized and characterized by IR, elemental analysis, TG technique and X-ray crystallography. Co(I) atom has a distorted trigonal pyramidal N2S2 (1) environment with two S atoms and one N atom from three μ-1,1,3-thiocyanate bridge ligands and one N atom from ql ligand. Two S atoms from two μ-1,1,3-SCN- bridging ligands bridge two centers to obtain bimetallic 4-membered ring. Adjacent 4-membered rings are linked by a pair of μ-1,1,3-SCN- bridging ligands to form a 1D stair-case like chain. The luminescent properties and magnetic properties of the polymer 1 were investigated in the solid state.