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It is still a great challenge to prepare novel CuO-based crystal materials with low-dimensional magnetic structures. A new copper oxyborate, namely, PbCu6B6O16 was synthesized and structurally characterized for the first time. Its structure features a novel 3D framework which can be considered as building from the layers of [Cu6B6O16]2−∞ interconnected by corner or edge sharing of CuO4、BO3、B2O5、and B3O7 groups, where Pb2+ cations are located in the free space within the layer. It is unexpected that the compound contains fundamental building block (FBB) formed by three different borate anionic groups, including BO3 triangle, and condensed branched BO3 triangles (B2O5 and B3O7). In particular, according to our survey, the branched B3O7 group is unprecedented. Our work provides useful information on the design and search for novel low dimensional copper borates, and also helps to strengthen the understanding of the investigation of borate structures.

The mid/far-infrared (MFIR) nonlinear optical (NLO) materials are very important for the development of new laser sources through laser frequency conversion technologies. In this work, two new noncentrosymmetric chalcogenide compounds Ba10In6Zn7S10Se16 (S10Se16) and Ba10In6Zn7Se26 (Se26) were successfully synthesized for MFIR NLO materials. They are composed of T2 super tetrahedron and show excellent comprehensive NLO performance. Their NLO coefficients are approximately 0.7 and 0.8 times of AgGaS2 at 2.05 μm, and both have high laser induced damage threshold (LIDT) about 12.3 and 10.0 times of AgGaS2, respectively. Both compounds show consistent melting characteristics, which is beneficial for the growth of large-size crystals. The band gaps, NLO coefficients, and density of states (DOS) of the crystals are calculated by first principles simulations to study the origination of NLO response, which indicates that the NLO performance of Se26 is mainly derived from tetrahedrons and supertetrahedrons composed of In/Zn and Se.

Two new selenite chlorides: Ba2Zn(SeO3)2Cl2 and BaZn2(SeO3)2Cl2 in the Ba-Zn-Se-oxychloride system have been synthesized from hydrothermal reaction. Ba2Zn(SeO3)2Cl2 crystalizes in a one-dimensional structure with 1D ∞1[Zn(SeO3)2Cl2]4- anionic chain composed of ZnO4Cl2 octahedra and lone-paired Ψ-SeO3 pyramids through sharing corner-oxygen atoms. BaZn2(SeO3)2Cl2 crystalizes in a double-layered architecture with 2D ∞2[Zn2(SeO3)2Cl2]2- anionic layer built up of SeO3 pyramids and ZnO3Cl tetrahedra through corner-sharing manner. Thermal properties of the title compounds were analyzed by means of thermogravimetric (TG) and differential scanning calorimetric (DSC) measurements. UV–Vis–NIR diffuse reflectance examinations for powder examples indicate that two compounds feature similar optical absorption spectra, and their optical band gaps can be estimated to be ~ 5.5 eV with direct band gap. Furthermore, the first-principal calculations were performed to investigate the electronic band structures and density of states, and the results further interpreted the relationship between crystal structures and optical properties.

In this work, we chose to explore the infrared (IR) nonlinear optical (NLO) materials centering on Cd and Ge elements, and finally synthesized a new IR NLO quaternary selenide BaCdGeSe4. Compound BaCdGeSe4 crystallizes in non-centrosymmetric (NCS) space group Fdd2 (No. 43), and it is built by parallel two-dimensional (2D) anionic [CdGeSe4]2- layers with the cation Ba2+ embedded between the layers. Under the 2050 ​nm laser excitation, compound BaCdGeSe4 appears type-I phase-matchable behavior and its second-harmonic generation intensities is about 0.5 times of AgGaS2.

A new mixed-metal phosphate of BaBi2CoP2O10 was synthesized by high temperature solution growth (HTSG) method and structurally characterized by X-ray single crystal diffraction and powder diffraction for the first time. The title compound crystallizes in the monoclinic system with space group P2(1)/c and represents the first compound in the Ba–Bi–M–P–O (M = transition metal) quinary anhydrous system, which structure features a novel 2D open framework which can be considered as building from the layers of [Bi2CoP2O10]2−∞ parallel to the bc plane interconnected by corner or bridge sharing of BiO5, BiO7, CoO6, and PO4 groups, where Ba2+ cations are located in the space between two adjacent layers. It is worth to note that the Bi3+ cations containing two kinds of coordinations (5 and 7) show stereochemically activities of their 6s2 lone pairs. The results of magnetic property measurements evidence on the antiferromagnetic property of BaBi2CoP2O10.

Two new bismuth(III) selenite/tellurite nitrates, [(Bi 3 O 2 )(SeO 3 ) 2 ](NO 3 ) and [Bi(TeO 3 )](NO 3 ), have been synthesized by conventional facile hydrothermal method at middle temperature 200 °C and characterized by single-crystal X-ray diffraction, powder diffraction, UV–vis–NIR optical absorption spectrum, infrared spectrum and thermal analylsis. Both [(Bi 3 O 2 )(SeO 3 ) 2 ](NO 3 ) and [Bi(TeO3)](NO3) crystallize in the monoclinic centronsymmetric space group P2 1 /c with a =9.9403(4) A, b =9.6857(4) A, c =10.6864(5) A, β= 93.1150(10)° for [(Bi 3 O 2 )(SeO 3 ) 2 ](NO 3 ) and a =8.1489(3) A, b =9.0663(4) A, c =7.4729(3) A, β= 114.899(2)° for Bi(TeO3)(NO3), respectively. The two compounds, whose structures are composed of three different asymmetric building units, exhibit two different types of structures. The structure of [(Bi 3 O 2 )(SeO 3 ) 2 ](NO 3 ) features a three-dimensional (3D) bismuth(III) selenite cationic tunnel structure [(Bi 3 O 2 )(SeO 3 ) 2 ] 3 ∞ with NO 3 − anion group filling in the 1D tunnel along b axis. The structure of [Bi(TeO 3 )](NO 3 ) features 2D bismuth(III) tellurite [Bi(TeO 3 ) 2 ] 2 ∞ layers separated by NO 3 − anion groups. The results of optical diffuse-reflectance spectrum measurements and electronic structure calculations based on density functional theory methods show that the two compounds are wide band-gap semiconductors.

A new polar compound Pb 2 (SeO 3 )(NO 3 ) 2 was synthesized by the conventional facile hydrothermal method at middle temperature 200 °C and characterized by X-ray single crystal diffraction, powder diffraction, UV–vis−NIR optical absorption spectrum and infrared spectrum. It crystallizes in the orthorhombic system, space group Pmn 2 1 with a = 5.4669(3) A, b = 10.3277(6) A, c = 7.2610(4) A, V = 409.96(4) A 3 . The compound features a 2D [Pb 2 (SeO 3 )] 2 ∞ architectures composed of SeO 3 and PbO 2 /PbO 3 units. Two unequivalent N(1)O 3 and N(2)O 3 units is inserted between adjacent [Pb 2 (SeO 3 )] 2 ∞ layers to stabilize the whole crystal structure. Second-harmonic generation (SHG) efficiency has been evaluated for powder Pb 2 (SeO 3 )(NO 3 ) 2 samples, showing about 2 times that of KDP reference. Moreover, the compound can achieve I-type phase-matching according to measurements by the Kurtz–Perry method. Theoretical investigations based on the first-principle DFT method were also performed to gain further insights into the crystal structure and optical properties relationship. The calculated band gap value of 3.38 eV is consistent with the optical reflectance measurements value of 3.76 eV.

The compound of Ba 2 Sb 7 O 13 (OH) was synthesized by using hydrothermal method from starting reagents of Ba(OH) 2 ·8H 2 O, Sb 2 O 3 and KCl. The crystal structure of Ba 2 Sb 7 O 13 (OH) was determined and characterized by single crystal X-ray diffraction method. Ba 2 Sb 7 O 13 (OH) represents a novel two-dimensional layered structure which is composed of Sb V O 6 and Sb III O 4 polyhedra through sharing corner oxygen atoms. Two types of Sb cations with Sb 3+ in sphenoid SbO 4 polyhedra and Sb 5+ in octahedral SbO 6 fashion are mixed in the crystal structure. First-principles electronic structure calculations based on the density functional theory (DFT), as well as the optical diffuse reflectance spectroscopy measurements, indicate that the compound belongs to an indirect band semiconductor with optical band gap of 2.7 eV.

First-principles calculations are performed to investigate linear electro-optical tensors and piezoelectric constants for zinc-blende compounds ZnX (X = O, S, Se, Te). The obtained results are compared with experimental and other theoretical results available. The findings are the followings: (1) there is no soft mode in these compounds because the electronic contributions and ionic contributions to the dielectric constants are of the same order of magnitude; (2) ZnO is the best candidate as an electro-optical material because of its largest electronic contribution to electro-optical effect among zinc-blende ZnX (X = O, S, Se, Te) compounds; (3) the abilities to resist volume compression, elastic deformation and linear compression reduce, and the second-order piezoelectric coefficients B 114 p become small from X = O to X = Te for ZnX (X = O, S, Se, Te) in turn.

A new ternary sulfide Ba 3 Sb 2 S 7 was synthesized from high temperature solid-state reactions in a flame-sealed silica ampoule. It crystallizes in the C 2/ c space group of the monoclinic system with a = 18.380(2) A, b = 12.266(2) A, c = 13.164(2) A, β = 110.054(6)°, V = 2788.0(7) A 3 , and Z = 8. The compound features an interesting zero-dimensional structure built of two types of isolated SbS 3 and SbS 2 (S 2 ) units surrounded with the charge balanced Ba 2+ cations. The UV–Vis–NIR optical diffuse reflectance measurements along with the electronic band structure calculations indicate that Ba 3 Sb 2 S 7 belongs to an indirect semiconductor with the band gap of 2.4 eV. Electronic density of states (DOS) analyses were also performed to interpret the intrinsic behavior of charge transfers in the SbS 3 and SbS 2 (S 2 ) units, respectively.

A new strontium antimonate{sup III}, Sr{sub 5}Sb{sub 22}O{sub 38}, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. It crystallizes in the P2{sub 1}/n space group of the monoclinic system with a=11.739(9) A, b=12.014(10) A, c=16.412(13) A, β=91.460(8)°, V=2314.0(3) A{sup 3}. The crystal structure is built of seven trigonal–pyramidal SbO{sub 3} and four sphenoid SbO{sub 4} polyhedra which are connected through sharing corner-oxygen atoms to form the complex three-dimensional {sub ∞}{sup 3}[Sb{sub 22}O{sub 38}]{sup 10−} anionic network with two different intersectant tunnels along the [111-bar ] and [11-bar 1-bar ] directions accommodating the electric charge balanced Sr{sup 2+} cations. First-principles electronic structure calculations based on the density functional theory (DFT) and the UV–vis diffuse reflectance spectroscopy measurements both indicate that the compound belongs to a direct band insulator with an optical gap value of 3.3 eV. - Graphical abstract: The 2D Sb–O slabs are stacked through sharing oxygen atoms to form the 3D network structure of the new strontium antimonate{sup III} Sr{sub 5}Sb{sub 22}O{sub 38}. - Highlights: • A new strontium antimonate{sup III}, Sr{sub 5}Sb{sub 22}O{sub 38}, has been hydrothermally synthesized. • The single crystal structure was determined by X-ray diffraction. • The powder XRD and UV–vismore » absorption spectroscopy were studied. • Theoretical studies interpret the relationships between optical absorption and crystal structure.« less

We used ab initio evolutionary algorithm to predict the stable and energetically competitive metastable structures of the nonlinear optical materials BiInS3 crystal. The powerful evolutionary algorithm allows us to find the global minimum of the energy landscape with dramatic reduced candidate numbers. Combining geometry optimization with density functional method and the phonon dispersion calculation it is possible for us to determine the stable structure of BiInS3 within only several tens of thousand candidates. The proposed most stable structure adopts the P21 space group, and its second-harmonic generation coefficient is as large as 59 pm/v. The former synthesized BiInS3 is probable corresponding to the metastable Pnma structure. The existence of iso-energy structures at the metastable energy range suggests that more delicate synthetic method is required to obtain high quality BiInS3 crystal.

We investigate the effect of side chain on the first-order hyperpolarizability in α-helical polyalanine peptide with the 10th alanine mutation (Acetyl(ala) 9 X(ala) 7 NH 2 ). Structures of various substituted peptides are optimized by ONIOM (DFT: AM1) scheme, and then linear and nonlinear optical properties are calculated by SOS//CIS/6-31G ∗ method. The polarizability and first-order hyperpolarizability increase obviously only when ‘X’ represents phenylalanine, tyrosine and tryptophan. We also discuss the origin of nonlinear optical response and determine what caused the increase of first-order hyperpolarizability. Our results strongly suggest that side chains containing benzene, phenol and indole have important contributions to first-order hyperpolarizability.

We report the frequency-dependent third-order polarizabilities ( γ ) of a series of hydrogen-capped silicon clusters obtained using time-dependent density functional theory. We find that the magnitude of γ increases with a decrease in silicon cluster size, while the sign of γ at low input photon energy changes from positive to negative when the ratio of hydrogen saturation increases. At higher input photon energy, the sign of γ is determined mainly by cluster size. Our results rationalize several recent experiments on the optical properties of silicon nanostructures and are helpful for designing opto-electronic devices based on them.

Two new barium indium phosphates BaIn2P4O14 and Ba3In2P4O16 were synthesized by high temperature solution growth method and structurally characterized by single crystal X-ray diffraction analysis. They represent first compounds in the Ba–In–P–O systems. BaIn2P4O14 and Ba3In2P4O16 display different types of 3D architectures. The projections of both structures concern about the existence of the intersecting tunnels. In compound BaIn2P4O14, the tunnels are built up of the corner-sharing InO6 octahedra and P2O7 groups, whereas in compound Ba3In2P4O16, they are formed by corner sharing of PO4 tetrahedra and InO6 octahedra. The electronic band structure calculations of two compounds have been performed with the density functional theory method. The study of calculations and optical diffuse reflectance experimental results show both compounds are insulators with direct band-gap.

Two members of MIII2BP3O12 borophosphates, namely Fe2BP3O12 and In2BP3O12, were synthesized by the solid-state method and characterized by the X-ray single crystal diffraction, the powder diffraction and the electron microscopy. They both crystallize in the hexagonal system, space group P6(3)/m (no. 176) and feature 3D architectures, build up of the M2O9 units and B(PO4)3 groups via sharing the corners; however, they are not isomorphic for the different crystallographically distinct atomic positions. Optical property measurements of both compounds and magnetic susceptibility measurements of Fe2BP3O12 also have been performed. Moreover, in order to gain further insights into the relationship between physical properties and band structure of the MIII2BP3O12 borophosphates, theoretical calculations based on density functional theory (DFT) were performed using the total-energy code CASTEP.

Two compounds Pb2In4P6O23 and Pb2InP3O11 in the new family of lead indium phosphates were synthesized by high temperature solution growth (HTSG) method and structurally characterized by X-ray single crystal diffraction, powder diffraction and electron microscopy. Two title compounds display different types of 3D architectures with interesting tunnel structure are built up of the InO6 octahedra and PO4 tetrahedra, sharing the corners or edges, and the Pb2+ cations are sitting in the tunnel. The structure of Pb2In4P6O23 features a novel 3D open framework which can be considered as built from the layer of {In4(P2O7)(PO4)2}2− parallel to the ac plane interconnected by bridging the single PO4. The structure of Pb2InP3O11 can be described by the assemblage of [InP2O11] units with monophosphate groups. The stereochemical activity of the PbII lone pair has also been discussed. The electronic band structure calculations for the two compounds have also been performed with the density functional theory method. The study of calculations and optical diffuse reflectance absorption spectrum measurement show both compounds are indirect band-gap insulators.

Solid-state reaction of K 2 CO 3 , Al 2 O 3 , TiO 2 and NH 4 H 2 PO 4 at 1000 °C leads to a new dipotassium aluminum titanium phosphate: K 2 AlTi(PO 4 ) 3 . Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the cubic space group P 2 1 3 (No. 198) with cell parameters of a = 9.76410(10) A and V = 930.886(17) A 3 . It belongs to the langbeinite [K 2 Mg 2 (S O 4 ) 3 ] structure type and its structure features a three-dimensional anionic network of [AlTi(PO 4 ) 3 ] 2− interconnected by K + cations. The elemental analysis, IR spectrum and UV-vis absorption spectrum have been investigated. Additionally, we also make the calculations of band structure and density of states with the density functional theory method for the title compound.

Two alkali–metal germanium phosphates, namely, NaGe2P3O12 and Cs2GeP4O13, have been synthesized by the solid-state reactions and their structures determined by single-crystal X-ray diffraction. The structure of NaGe2P3O12 features a Nasicon-type structure, crystallizing in space group R 3 ¯ with a = 8.109(2), c = 21.536(8) (A), V = 1226.3(6) A3, Z = 6, R1 = 0.0383 and ωR = 0.0960; Cs2GeP4O13 crystallizes in triclinic space group P 1 ¯ with a = 9.420(3), b = 10.209(4), c = 12.407(4) (A), α = 104.136(6), β = 108.132(5), γ = 95.338(6)°, V = 1081.0(7) A3, Z = 2, R1 = 0.0445 and ωR = 0.1117. Additionally, the calculations of band structure and density of states were performed with the density functional theory method for the title compounds. The results show that the solid-state compounds of NaGe2P3O12 and Cs2GeP4O13 are insulator with indirect band-gap of 3.529 and 3.888 eV, respectively.

Two tertiary rare earth polyphosphates, namely, LiM(PO3)4 (M = Y, Dy), have been synthesized by the solid-state reaction and structurally established by single-crystal X-ray diffraction (XRD). The two compounds crystallize in monoclinic space group C2/c and Z = 4. They are isostructural and the structures feature interconnected Y–Li straight chains and [PO4]3− wavy chains. Additionally, the calculations of band structure, density of states of LiY(PO3)4 were performed with the density functional theoretical (DFT) method and the optical properties of LiDy(PO3)4 were investigated in terms of emission spectra.

The structural, optical, and electronic properties of a series of lithium rare earth polyphosphates [LiLn(PO3)4] [Ln = Tb(1), Ho(2), Yb(3)] have been investigated by means of single-crystal X-ray diffraction, spectroscopic measurements and calculations of energy-band structures, density of states, and optical response functions by density functional methods. These LiLn(PO3)4 systems are monoclinic with space group C2/c and Z = 4. Their unit-cell parameters decrease as the ionic radius of Ln3+ decreases (Tb3+ > Ho3+ > Yb3+). Both (PO4)3− zig-zag chains and infinite chains formed by the alternate connection of LnO8 polyhedra and LiO4 tetrahedra run parallel to the b-axis in the structure. The energy-band structures, density of states, the chemical bonds, and optical properties have been investigated by density functional methods for LiYb(PO3)4.

A sodium gadolinium phosphate crystal, Na 3 GdP 2 O 8 , has been synthesized by a high-temperature solution reaction, and it exhibits a new structural family of the alkali-metal-rare-earth phosphate system. Although many compounds with formula M 3 LnP 2 O 8 have been reported, but they were shown to be orthorhombic [R. Salmon, C. Parent, M. Vlasse, G. LeFlem, Mater. Res. Bull. 13 (1978) 439] rather than monoclinic as shown in this paper. Single-crystal X-ray diffraction analysis shows the structure to be monoclinic with space group C 2/ c and the cell parameters: a =27.55 (25), b =5.312 (4), c =13.935(11) A, β =91.30(1)°, and V =2038.80 A 3 , Z =4. Its structure features a three-dimensional GdP 2 O 8 3− anionic framework with two different types of interesting tunnels at where Na atoms are located by different manners. The framework is constructed by Gd polyhedra and isolated PO 4 tetrahedra. It is different from the structure of K 3 NdP 2 O 8 [R. Salmon, C. Parent, M. Vlasse, G. LeFlem, Mater. Res. Bull. 13 (1978) 439] with space group P 2 1 / m that shows only one type of tunnel. The emission spectrum and the absorption spectrum of the compound have been investigated. Additionally, the calculations of band structure, density of states, dielectric constants, and refractive indexes have been also performed with the density functional theory method. The obtained results tend to support the experimental data.

Sodium rare earth diphosphates NaLnP2O7 (Ln = Ce (1), Eu (2)) and polyphosphates NaLn(PO3)4 (Ln = Ce (3), Eu (4)) have been synthesized by the high temperature solution reaction. These compounds have been characterized by means of single-crystal X-ray diffraction, elemental analyses, spectral measurements, and theoretical computations. Their structural characteristics are described, and the differences among them are compared. The nature of chemical bonds and electronic origins of optical transitions are analyzed for 1 and 3 in terms of crystal band structures, density of states (DOS), and optical response functions which have been calculated by the DFT method. Results of spectral measurements indicate that crystals 1 and 3 may become promising hosts for ultraviolet-emitting solid-state light sources, and crystals 2 and 4 exhibit the characteristic yellow–red light emission under the excitation of ultraviolet light.

Self-assembly of CdI2 with flexible unsymmetric ligands pybta and pyta [pybta = N-(3-pyridylmethyl)benzotriazole, pyta = 1-(4-pyridylmethyl)(1,2,4-triazole)], respectively, by layer-separating diffusion method at ambient temperature gives rise to two new supramolecular architectures [Cd3(pybta)4I6]n (1) and [Cd(pyta)2I2]n (2). 1 crystallizes in the triclinic system, space group P-1, with cell parameters M = 1939.56, a = 8.5269(3) A, b = 13.2387(2) A, c = 13.9066(4) A, α = 71.927(5)°, β = 83.180(7)°, γ = 81.002(7)°, V = 1469.90(7) A3, Z = 1, R1[I > 2σ(I)] = 0.0361, wR2 [I > 2σ(I)] = 0.0889. 2 crystallizes in the monoclinic system, space group P21/c, with cell parameters M = 686.57, a = 8.1754(11) A, b = 16.5254(14) A, c = 8.9068(10) A, β = 116.434(4)°, V = 1077.5(2) A3, Z = 2, R1[I > 2σ(I)] = 0.0214, wR2 [I > 2σ(I)] = 0.0483. Complex 1 displays a 1D double-stranded chain structure consisting of tri-nuclear [Cd3(pybta)2I6] subunits, as well as complex 2 exhibits an usual 2D 44 sheet structure. The thermal property associated with their crystal structures has also been measured.

Trinuclear copper(II) complex of [Cu3L2(H2O)2] · 2ClO4 · 3H2O was prepared by the reaction of (2-picoloylcarbonyl)thiosemicarbazone(H2L) and copper perchlorate hydrate, and the magnetic properties and absorption spectra were measured for the title compound, and the origin of third-order optical response was identified in terms of calculated results using density functional theory combined with sum-over-states methods.

Ternary indium (III) phosphates with three-dimensional frameworks, [M{sub 3}In(PO{sub 4}){sub 2}]{sub n} (M=K, n=10; M=Rb, n=2), are found and firstly reported in this paper. These compounds have been obtained by high temperature solid-state reactions and their crystal structures have been determined by single crystal X-ray diffraction analysis. The title compounds, which crystallize in monoclinic system, possess the same [In(PO{sub 4}){sub 2}]{sub n}{sup 3n-} anionic frameworks built up from interconnected InO{sub 6} octahedra and PO{sub 4} tetrahedra and have an interesting tunnel structure where M{sup +} cations are located. Optical and bonding properties of [Rb{sub 3}In(PO{sub 4}){sub 2}]{sub 2} are investigated in terms of measured absorption and emission spectra, and calculated band structures and density of states. The crystal band structures obtained by the DFT method show that the solid compound of [Rb{sub 3}In(PO{sub 4}){sub 2}]{sub 2} is an insulator with direct band gap, and the P-O covalent bond characters are larger than the In-O ones in this compound.

The compound Sr 2 B 2 O 5 has been synthesized by high temperature solution reaction. It crystallizes in the monoclinic space group P 2 1 / c with cell dimensions a =7.719(4), b =5.341(1), c =11.873(2)A, β =92.71(2)°, V =488.9(3) A 3 , and Z =4, D calc =3.76 g/cm 3 . The structure comprises SrO 7 and SrO 6 polyhedra and B 2 O 5 groups. The electronic structure has been calculated by the INDO/S method for this compound, and the dynamic refractive indices have been obtained in terms of INDO/SCI following combination with the sum-over-states method. The calculated energy gap is 4.26 eV between the upper valence band and lower conduction band, and the calculated average refractive index is 1.791 at a wavelength of 1.065 μm. The charge transfers from O 2− anion orbitals to Sr 2+ cation orbitals make the significant contributions to linear polarizability in terms of analyses of atomic state density contributing to the valence and conduction bands.

Reaction of NiCl2 · 6H2O, Na2[i-mnt] and benzo-15-crown-5 in CH3OH⧹CH2Cl2 at room temperature leads to [{Na(benzo-15-crown-5)}2Ni(i-mnt)2]n · nCH2Cl2 (1). The same reaction with Na2[mnt] instead of Na2[i-mnt] affords [{Na(benzo-15-crown-5)}2Ni(mnt)2]n (2). Both complexes were isolated as crystalline products. X-ray diffraction analyses reveal that the main segments of 1 and 2 are infinite train structures, in which the building blocks Ni(i-mnt)2 or Ni(mnt)2 in end-to-end arrangements act as body frames and crown cycles standing by the body frames play the role of cartwheel. They are joined with each other through sodium ions.

The electronic structures of the ground state have been calculated using the INDO/1-SCI method, and in combination with the sum-over-states method, the first and second frequency dependent polarizabilities have been obtained for microscopic species of K 3− x Li 2+ x Nb 5 O 15 with x = 0 and x = 1. The calculated birefringences δn and phase matching nonlinear optical coefficients d 31 indicate that the K 3− x Li 2+ x Nb 5 O 15 with higher lithium content will enhance nonlinear optical effects at the fundamental wavelengths of 1064 and 820 nm. The charge transfer states formed from oxygen atomic 2p orbitals with a mixing of niobium atomic 4d character to alkali metal atomic valence orbitals with mixing of niobium 5s, 5p character make the most significant contributions to the susceptibility.

The electronic structure of the ground state and electronic transition energies of low-lying states have been calculated using the INDO/S-CI method for Mo3X4(aq)4+9 cluster ions(X=O, S). It has been shown that the calculated values are in accordance with those observed experimentally, allowing us to assign the bands. The lowest absorption band results from the dipole-forbidden but spin-allowed electron transition 1 1A1→1 1A2 state, and it has been assigned as arising from a metal-based bonding orbital to a metal-based antibonding orbital. The singlet-triplet energy splitting of the two lowest excited states, A2, E, have been estimated to be about 2400 and 3350 cm−1, respectively, and a red-shift of the absorption bands has been explained by comparing X=S with X=O for the Mo3X4(aq)4+9 ions.

A new quaternary compound Ba 3 F 2 MnSe 3 was synthesized by using a high-temperature solid-state reaction method in closed silica tubes at 1253 K. The compound displays an infinite one-dimensional corner-sharing MnSe 3 tetragonal chain separated by 1D 1 ∞ [Ba 3 F 2 ] 4 + cationic chains of the fluorite type. Magnetic susceptibility results verify the presence of the antiferromagnetic short-range order at low temperature.