A rare multi-coordinate tellurite, NH4ATe4O9·2H2O (ARb or Cs): The occurrence of TeO3, TeO4, and TeO5 Polyhedra in the same material

Understanding of the structural chemistry in the uranium oxo-tellurium system under HT/HP conditions

The study of phase formation in the U-Te-O systems with mono and divalent cations under high-temperature high-pressure (HT/HP) conditions has resulted in four new inorganic compounds: K2 [(UO2) (Te2O7)], Mg [(UO2) (TeO3)2], Sr [(UO2) (TeO3)2] and Sr [(UO2) (TeO5)]. Tellurium occurs as TeIV, TeV, and TeVI in these phases which demonstrate the high chemical flexibility of the system. Uranium VI) adopts a variety of coordinations, namely, UO6 in K2 [(UO2) (Te2O7), UO7 in Mg [(UO2) (TeO3)2] and Sr [(UO2) (TeO3)2], and UO8 in Sr [(UO2) (TeO5)]. The structure of K2 [(UO2) (Te2O7)] is featured with one dimensional (1D) [Te2O7]4- chains along the c-axis. The Te2O7 chains are further linked by UO6 polyhedra, forming the 3D [(UO2) (Te2O7)]2- anionic frameworks. In Mg [(UO2) (TeO3)2], TeO4 disphenoids share common corners with each other resulting in infinite 1D chains of [(TeO3)2]4- propagating along the a-axis. These chains link the uranyl bipyramids by edge sharing along two edges of the disphenoids, resulting in the 2D layered structure of [(UO2) (Te2O6)]2-. The structure of Sr [(UO2) (TeO3)2] is based on 1D chains of [(UO2) (TeO3)2]∞2− propagating into the c-axis. These chains are formed by edge-sharing uranyl bipyramids which are additionally fused together by two TeO4 disphenoids, which also share two edges. The 3D framework structure of Sr [(UO2) (TeO5)] is composed of 1D [TeO5]4− chains sharing edges with UO7 bipyramids. Three tunnels based on 6-Membered rings (MRs) are propagating along [001] [010] and [100] directions. The HT/HP synthetic conditions for the preparation of single crystalline samples and their structural aspects are discussed in this work.

Kyropoulos growth and characterization of monoclinic α-Bi2B8O15 single crystal with a noncentrosymmetric structure

A high-quality crystalline α-Bi2B8O15 crystal is grown by the Kyropoulos method that might have potential for opto-electric applications.

Bi32Cd3P10O76: a new congruently melting nonlinear optical crystal with a large SHG response and a wide transparent region

Large size single crystal Bi₃₂Cd₃P₁₀O₇₆ with a large SHG response (4 × KDP) and a wide transmission range covering 0.36–4.9 μm.

Rb21.89W32.66O108: An Excellent Mid- and Far-IR Nonlinear-Optical Material with a Wide Band Gap

IR nonlinear-optical (NLO) crystal is the important device in IR laser technology. Nevertheless, the application of most IR NLO crystals in high-power lasers is always limited by the low laser damage threshold (LDT), which is mainly caused by the narrow optical band gap (E_g). Here, the physical properties of the Rb_21.89W_32.66O₁₀₈ (RWO) crystal with a longer absorption cutoff edge and a wide E_g were systematically studied for the first time. A preliminary measurement of the LDT was performed, and the result shows that RWO has a high powder LDT of about 42 times that of AgGaS₂. In order to better understand the relationship between the structure and properties, the dipole moments of WO₆ octahedra were accurately calculated and analyzed. Meanwhile, it was indicated that RWO exhibits an ideal frequency doubling strength with the type I phase matching. Finally, it was revealed that RWO has great application value as an IR NLO crystal.

Electro-elastic features of Nd-doped YAl3(BO3)4 single crystal

The NYAB crystal shows relatively high resistivity and good temperature stability of piezoelectric activity, potential for high temperature piezoelectric applications.

PbSrSiO4: a new ultraviolet nonlinear optical material with a strong second harmonic generation response and moderate birefringence

PbSrSiO₄ exhibits excellent properties, including a strong second harmonic generation response (∼5.8 × KDP), a short UV cut-off edge (240 nm) and moderate birefringence (0.053@1064 nm).

Pb10O4(BO3)3I3: a new noncentrosymmetric oxyborate iodide synthesized by the straightforward hydrothermal method

A new first reported oxyborate iodide Pb₁₀O₄(BO₃)₃I₃ has been synthesized by a straightforward hydrothermal method.

Insights into the polymorphism of Bi2W2O9: single crystal growth and a complete survey of the variable-temperature thermal and dielectric properties

A single crystal of the Aurivillius phase Bi₂W₂O₉ and its polymorphous evolution sequences from the experimental perspective.

Thorium Chemistry in Oxo-Tellurium System under Extreme Conditions

Through the use of a high-temperature/high-pressure synthesis method, four thorium oxo-tellurium compounds with different tellurium valence states were isolated. The novel inorganic phases illustrate the intrinsic complexity of the actinide tellurium chemistry under extreme conditions of pressure and temperature. Th₂Te₃O₁₁ is the first instance of a mixed-valent oxo-tellurium compound, and at the same time, Te exhibits three different coordination environments (Te^IVO₃, Te^IVO₄, and Te^VIO₆) within a single structure. These three types of Te polyhedra are further fused together, resulting in a [Te₃O₁₁]^8- fragment. Na₄Th₂(Te^VI₃O₁₅) and K₂Th(Te^VIO₄)₃ are the first alkaline thorium tellurates described in the literature. Both compounds are constructed from ThO₉ tricapped trigonal prisms and Te^VIO₆ octahedra. Na₄Th₂(Te^VI₃O₁₅) is a three-dimensional framework based on Th₂O₁₅ and Te₂O₁₀ dimers, while K₂Th(Te^VIO₄)₃ contains tungsten oxide bronze like Te layers linked by ThO₉ polyhedra. The structure of β-Th(Te^IVO₃)(SO₄) is built from infinite thorium chains cross-linked by Te^IVO₃^2- and SO₄^2- anions. Close structural analysis suggests that β-Th(Te^IVO₃)(SO₄) is highly related to the structure of α-Th(SeO₄)₂. Additionally, the Raman spectra are recorded and the characteristic peaks are assigned based on a comparison of reported tellurites or tellurates.

A new one-dimensional strontium vanadium tellurite, Sr7V4Te12O41

Vanadium tellurites display a rich structural chemistry with interesting physical properties, such as second harmonic generation (SHG). Tellurites, i.e. Te(4+)Ox, are often observed in unusual structures and form various structural motifs, including isolated clusters, chains, layers, and three-dimensional networks. Similarly, vanadates, i.e. V(5+)Ox, show rich structural features, such as VO4 tetrahedra, VO5 square pyramids or trigonal bipyramids, and VO6 octahedra. Strontium vanadium tellurite, Sr7V4Te12O41, was obtained from the melt of the solid-state reaction of SrTeO4 and VO2 in a sealed quartz tube as it cooled from 973 K. The crystal structure exhibits a one-dimensional latticework along the a axis comprised of paired Sr3Te3Ox units, namely Sr6Te6O2x+1, with corner-shared TeO4 polyhedra - and specifically the Te lone-pair electrons - facing outward in the bc plane. The Sr6Te6O2x+1 latticework is helical and is layered in the b-axis direction against sheets of corner-shared VO4 tetrahedra, and is linked in the c-axis direction via individual corner-shared SrO8 square prisms.

Rich Non-centrosymmetry in a Na-U-Te Oxo-System Achieved under Extreme Conditions

Two new sodium uranyl tellurites and two new sodium uranyl tellurates have been synthesized from high-temperature/high-pressure conditions and structurally characterized. We demonstrated that crystalline phases, forming in a Na-U-Te system under extreme conditions, appear to favorably have non-centrosymmetric structures. Three out of four novel uranyl tellurium compounds, Na[(UO2)Te(IV)2O5(OH)], Na2[(UO2)(Te(VI)2O8)], and Na2[(UO2)Te(VI)O5], crystallize in non-centrosymmetric space groups. The crystal structure of Na[(UO2)Te(IV)2O5(OH)] is based on two-dimensional [UO2Te2O5(OH)](-) corrugated sheets, which are charge balanced by guest Na(+) cations. The structure of Na2[(UO2)Te(VI)2O8] is constructed from [(UO2)2Te2O8](2+) anionic layers composed of UO7 pentagonal bipyramids and TeO6 octahedra. Na2[(UO2)(Te(VI)O5)] is a new type of three-dimensional anionic open framework built from the interconnection of UO7 pentagonal bipyramids and TeO6 octahedra with different types of interlacing channels within the U-Te anionic framework. Na[(UO2)Te(IV)6O13(OH)], as the only centrosymmetric compound isolated in the Na-U-Te family, is crystallized in space group Pa3̅, and its structure is highly related to that of cliffordite (UO2(Te3O7)), which is composed from UO8 hexagonal bipyramids and TeO5 square pyramids. The vibrational modes associated with U-O, Te(IV)-O, and Te(VI)-O bonds are discussed, and the Raman spectra of the four compounds are characterized for signature bands.

BaCdSnS4and Ba3CdSn2S8: syntheses, structures, and non-linear optical and photoluminescence properties

Good non-linear optical performances and promising photoluminescence properties for the title compounds were systemically reported for the first time.

Experimental and theoretical studies on the linear and nonlinear optical properties of lead phosphate crystals LiPbPO4

LiPbPO₄achieved a desired balance between UV transparency (232 nm) and high nonlinear optical (NLO) activity (about 3 × KDP).

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.

Cs4Mo5P2O22: a first Strandberg-type POM with 1D straight chains of polymerized [Mo5P2O23]6- units and moderate second harmonic generation response

A noncentrosymmetric chiral Strandberg-type polyoxometalate based material, Cs(4)Mo(5)P(2)O(22), that contains unusual one dimensional chains constructed from [Mo(5)P(2)O(23)](6-) units has been reported. Cs(4)Mo(5)P(2)O(22) shows a moderate SHG response, and is phase-matchable.

A high-pressure single-crystal synchrotron diffraction study of NH4RbTe4O9·2H2O: stability of three different TeO(x) coordination polyhedra

The crystal structure of ammonium rubidium nonaoxotetratellurate(IV) dihydrate has been studied as a function of pressure up to 7.40 GPa. The ambient-pressure structure is characterized by the co-existence of three different Te-O polyhedra (TeO(3), TeO(4) and TeO(5)), which are connected to form layers. NH(4)(+), H(2)O and Rb(+) are incorporated between the layers. Both the Rb1 position, which is located on a twofold axis, and the Rb2 position are partially occupied. The three different types of coordination polyhedra around Te(4+) are stable up to at least 5.05 GPa. No phase transition is observed. The fit of the unit-cell volume as a function of pressure gives a zero-pressure bulk modulus of 34 (1) GPa with a zero-pressure volume of V(0) = 2620 (4) Å(3) [B' = 1.4 (2)].

First-principles study of the ferroelectric and nonlinear optical properties of the LiNbO3-type ZnSnO3

Electronic structures, spontaneous polarization, dynamical and nonlinear optical (NLO) properties of polar oxide ZnSnO(3) with LiNbO(3) (LN)-type structure have been investigated in the framework of density functional theory. By analyzing the Born effectives of LN-type ZnSnO(3), we find that Z* of Zn atoms show relatively large anomalous behavior. The spontaneous polarization is attributed to the large displacement of Zn atoms because of the mixed ionic-covalent character between the Zn-O bonds. The optical dielectric tensor is nearly the same; however the static dielectric tensor shows strongly anisotropy. Furthermore, the nonlinear optical properties are calculated by using 2n + 1 theorem applied to an electric-field dependent energy functional. The large dielectric constants and NLO susceptibilities indicate that the LN-type ZnSnO(3) would be a candidate as a high-performance dielectric and nonlinear optical material.