Lix(Sr0.5Ba0.5)1-x/2Nb2O6 ceramics were prepared by a solid state synthesis and sintered at 1300 degrees C. XRD investigations reveal single phase samples up to a substitution limit of x = 0.275. For higher lithium contents, the appearance of LiNbO3 as secondary phase was observed. The density of the ceramics increases with lithium content. The microstructures show globular grains which turns to pillar-like grains with rising lithium substitution. Dielectric investigations confirm relaxor ferroelectric behavior and the diffuse phase transition is shifted towards higher temperatures with increasing lithium content from 129 degrees C (x = 0) to 221 degrees C (x = 0.275). The diffuseness coefficient increases with the lithium content. From high-temperature XRD measurements the length of the tetragonal cell parameter c decreases with increasing temperature, reaches a minimum at about 150 -230 degrees C (depending on x) and afterward increases with increasing temperature. Additionally, a significant shift of the Nb(2) position with temperature can be observed.

Magnetoelectric (NixCo1_xFe2O4)0.3_ (SryBa1_yNb2O6)0.7 composites with a 0-3 connectivity and different cation stoichiometries were synthesized via a classical mixed-oxide method. XRD patterns of all ceramics show reflections of the target phases SryBa1_yNb2O6 and NixCo1_xFe2O4. The influence of stoichiometry of the ferrimagnetic and ferroelectric phase on the magnetoelectric behavior was studied on composites with composition of (NixCo1_ x Fe 2 O 4 ) 0.3 _ (Sr 0.5 Ba 0.5 Nb 2 O 6 ) 0.7 and (NiFe 2 O 4 ) 0.3 _ (SryBa1_yNb2O6)0.7. The magnetic Curie temperature increases with nickel content. However, the saturation magnetizations as well as the Curie temperatures of the composites are always lower than the ones of bulk NixCo1_xFe2O4 samples. The maximum magnetoelectric coefficient (alpha ME) rises with increasing nickel content from 40 (x = 0) to 180 mu V Oe _ 1 cm _ 1 (x = 1) in accordance with the dynamic magnetostriction coefficient. The evolution of alpha ME of (NiFe2O4)0.3_ (SryBa1_yNb2O6)0.7 composites shows an increase with strontium content up to y 0.5. Higher strontium content leads to a significant reducing of alpha ME.

Magnetoelectric (NixCo1-xFe2O4)0.3-(SryBa1-yNb2O6)0.7 composites with a 0–3 connectivity and different cationstoichiometries were synthesized via a classical mixed-oxide method. XRD patterns of all ceramics show reflectionsof the target phases SryBa1-yNb2O6 and NixCo1-xFe2O4. The influence of stoichiometry of the ferrimagneticand ferroelectric phase on the magnetoelectric behavior was studied on composites with composition of(NixCo1-xFe2O4)0.3-(Sr0.5Ba0.5Nb2O6)0.7 and (NiFe2O4)0.3-(SryBa1-yNb2O6)0.7. The magnetic Curie temperatureincreases with nickel content. However, the saturation magnetizations as well as the Curie temperatures of thecomposites are always lower than the ones of bulk NixCo1-xFe2O4 samples. The maximum magnetoelectric coefficient(αME) rises with increasing nickel content from 40 (x = 0) to 180 μV Oe-1 cm-1 (x = 1) in accordancewith the dynamic magnetostriction coefficient. The evolution of αME of (NiFe2O4)0.3-(SryBa1-yNb2O6)0.7 compositesshows an increase with strontium content up to y 0.5. Higher strontium content leads to a significantreducing of αME.

The peculiar adsorption-induced phase transitions in an ultramicroporous copper phosphonate framework were investigated with a combination of experimental and computational methods.

In this study, unique hybrid structures were constructed between a Ce-based metal-organic framework (Ce-MOF) and graphitic carbon nitride (g-C3N4) materials. In addition, the g-C3N4 materials used for these heterostructures were prepared by five different methods, namely the conventional pyrolysis method, chemical exfoliation by a strong acid, activation by an alkaline hydrothermal treatment, melamine-cyanuric acid supramolecular assembly with a mechanochemical method, and by the solvothermally pre-treated method. The structural and morphological properties of the resulting g-C3N4 sheets and their composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis-derivative thermogravimetry (TGA-DTG), diffuse reflectance UV–vis spectroscopy (UV–vis DRS) and N2 sorption-desorption isotherms (BET). Finally, the photocatalytic performance of the composites was determined by following the photocatalytic degradation of methylene blue (MB) in an aqueous solution under UV–visible light irradiation. It was found that the photocatalytic efficiency of the Ce-MOF/g-C3N4‒TS composite was significantly higher than that of their counterparts (Ce-MOF or g-C3N4‒TS) for the photocatalytic degradation of MB. When employing the composite, UV light-induced degradation of MB yielded an efficiency of 96.5% after 120 min for a dye solution containing 10 mg/L MB. This corresponds to a 5-fold or 2-fold improvement of the rate constant (k) when compared to the Ce-MOF or g-C3N4, respectively.

Magnetoelectric (NiFe2O4)0.3-(Sr0.5Ba0.5Nb2O6)0.7 composites with addition of LiNbO3 as sintering additivewere prepared by a classical mixed-oxide method. XRD patterns of ceramics sintered between 1000 and 1200 ◦Cshow the desired Sr0.5Ba0.5Nb2O6 and NiFe2O4 phases. SEM investigations confirm the 0–3 connectivity of thecomposite ceramics. The addition of 10 and 20 mol% LiNbO3 improves the densification of the composite ceramicsand leads to an increase of the size of the Sr0.5Ba0.5Nb2O6 grains. Magnetic measurements show hystereseswith low coercivities. Dielectric measurements were carried out depending on temperature and frequency. Thesamples with the LiNbO3 addition show significantly higher resistivity values (σDC). Magnetoelectric measurementswere carried out in dependence of the magnetic DC-field, temperature, and frequency. The maximummagnetoelectric coefficient (αME) rises with the addition of LiNbO3 from 180 to 803 μV Oe-1 cm-1 (@900 Hz).Temperature dependent measurements show a continuously decreasing of αME with lower temperature.

Magnetoelectric (Sr0.5Ba0.5Nb2O6)1x(CoFe2O4)x (x = 0.2–0.6) composites were prepared by a one-pot softchemistrysynthesis using PEG400. Calcining at 700 ◦C resulted in nanocrystalline composite powders (dcryst. =24–30 nm) which were sintered between 1050 and 1200 ◦C to ceramic bodies with relative densities up to 98%.SEM investigations confirm the formation of composite ceramics with a 0–3 connectivity and variable grain sizesfrom 0.2 to 3.6 μm for sintering up to 1150 ◦C, while sintering at 1200 ◦C leads both to a change in themicrostructure and a considerable grain growth. Magnetic measurements at 300 K reveal ferrimagnetic behaviourwith saturation magnetization values smaller than bulk CoFe2O4 and coercivities between 790 and 160 Oe.Temperature-dependent impedance spectroscopy showed that the relative permittivities decrease both withrising frequency and CoFe2O4 fraction. The frequency dependence of the impedance can be well described usinga single RC circuit. Magnetoelectric measurements show the presence of pronounced field hystereses. Themaximum magnetoelectric coefficient (αME) depends both on the CoFe2O4 fraction (x) and sintering temperature.The composite with x = 0.3 exhibits the largest αME value of 37 μV Oe1 cm1 (@ 900 Hz). With rising frequencyof the AC driving field αME increases up to 300–400 Hz and is nearly constant until 1 kHz.

Nano-crystalline Sr0.5Ba0.5Nb2O6 powders with addition of LiNbO3 or LiF as sintering additives were prepared bya soft-chemistry synthesis using polyethylene glycol. Calcination at 600 ?C results in nanocrystalline powders(dcryst. ? 30 nm) which were sintered between 1000 and 1300 ?C to ceramic bodies. By addition of 10 and 20 mol% LiNbO3, the sintering temperature was reduced by about 200 K and the activation energy of the initial stage ofsintering decreases from 386 to 271 kJ mol?1. The sintering aid improves the grain growth and dense ceramicbodies were obtained after sintering at 1125 ?C for 1 h. A higher LiNbO3 content favors the formation of a pillarlikemicrostructure. XRD patterns of ceramics sintered above 1000 ?C show only reflections of the Sr0.5Ba0.5Nb2O6phase indicating an incorporation of LiNbO3 in the Sr0.5Ba0.5Nb2O6 structure. Dielectric measurements reveal adiffuse phase transition and a relaxor-like behavior. The phase transition temperature (Tm) depends on the sinteringconditions and is between 117 and 127 ?C for 10 mol% LiNbO3, which is very close to pureSr0.5Ba0.5Nb2O6, while addition of 20 mol% shifts Tm to around 200 ?C and the transition becomes slightly morediffuse. The optical band gap of the samples is ? 3.3 eV and depends slightly on the sintering conditions. We alsotried LiF as sintering aid, but this leads to the formation of considerable amounts of secondary phases in theceramics and relative densities of only 82%.

Monoclinic single crystals of Co[(C 6 H 10 )(NH 3 ) 2 ][C 6 H 2 (COO) 4 ] · 2H 2 O have been prepared in aqueous solution at 80 °C. Space group C2/c (no. 15), a = 1065.92(8), b = 1568.97(9), c = 1140.88(9) pm, β = 90.101(6)°, V = 1.9080(2) nm 3 , Z = 4. Co 2+ , which is situated on a twofold crystallographic axis, is coordinated in a moderately distorted tetrahedral fashion by four oxygen atoms stemming from the pyromellitate anions (Co-O 197.87(12) and 200.64(12) pm). A three-dimensionally connected coordination polymer is made up by Co 2+ and C 6 H 2 (COO) 44-featuring channel-like voids, which accomodate water molecules and (C 6 H 10 )(NH 3 ) 22+ cations compensating for the negative excess charge of the three-dimensional framework. Thermogravimetric analysis in air showed that the dehydrated compound was stable between 198 and 361 °C. Further decomposition yielded CoO.

Nanocrystalline Li0.5Fe2.5O4 was prepared by a starch-based soft-chemistry synthesis. Calcining of the (LiFe)-gel between 350 and 1000 °C results in Li0.5Fe2.5O4powders with crystallite sizes from 13 to 141 nm and specific surface areas between 35 and 7.1 m2 g−1. XRD investigations reveal the formation of ordered Li0.5Fe2.5O4. Sintering between 1050 and 1250 °C leads to ceramics with relative densities of 67−95 % consisting ofgrains between 0.3 and 54 μm. As the sintering temperature increases a rising weight loss ofthe ceramic samples was observed due to the loss of Li2O. Temperature-dependent magnetic measurements indicate a superparamagnetic behaviour for the nano-sized samples. Field-dependent measurements at 3 K of ceramics sintered between 1050 and 1200 °C showincreasing saturation magnetization values (Ms) of 70.0 to 73.0 emu g−1 most likely due to the formation of lithium vacancies and a decrease of the inversion parameter. The magnetization drops down to 67.7 emu g−1 after sintering at 1250 °C caused by the formation of hematite.Diffuse reflectance spectra reveal an indirect allowed band gap decreasing from 1.93 to 1.60 eV depending on thermal treatment. DSC measurements of the order - disorder phase transition on nano-sized powders and bulk ceramics exhibit transition temperatures between 734 and 755 °C and enthalpy changes (ΔtrsH) ranging from 5.0 to 13.5 J g−1. The linear starch was found to be 11.4⋅10−6 K−1.

Blue monoclinic single crystals of the novel one-dimensional [H3N-(CH2)6-NH3][Cu(H2O)2(urea)(µ2-C6(COO)4 (COOH)2)]*H2O coordination polymer have been prepared in aqueous solution at room temperature in the presence of 1,6-diaminohexane and urea. Space group P21/n (no. 14) with a = 958.48(9), b = 1465.74(11), c = 1821.14(12) pm, beta = 97.655(8)°. The Cu2+ cation is coordinated in a square pyramidal manner by two oxygen atoms stemming from the dihydrogen mellitate tetraanion, one oxygen atom from the urea molecule, and two water molecules. The Cu−O distances are between 193.3(2) and 229.4(2) pm. The connection between Cu2+ and [C6(COO)4(COOH)2]4-

. Monoclinic single crystals of Ba 2 (H 2 O)[ μ 10 -C 6 H 2 (COO) 4 ] ( 1 ) and Pb 2 (H 2 O)[ μ 10 C 6 H 2 (COO) 4 ] ( 2 ) were obtained using the silica gel method [space group C 2/ c (no. 15), Z = 4; 1 : a = 780.89(4), b = 1756.19(8), c = 914.80(5) pm, β = 114.512(5)°; 2 : a = 756.70(10), b = 1772.8(2), c = 890.2(2) pm, β = 113.590(10)°]. There are two crystallographically independent M 2+ ions ( M = Ba, Pb). M (1) is surrounded by eight carboxylate oxygen atoms and one water molecule forming a tricapped trigonal prism. M (2) is coordinated by ten carboxylate oxygen atoms in the shape of a tetracapped octahedron. The connection between the M (1) and M (2) polyhedra leads to infinite layers parallel to (010), which are linked by [C 6 H 2 (COO) 4 ] 4 – anions to form a three-dimensional framework. The [C 6 H 2 (COO) 4 ] 4 – anion adopts a μ 10 coordination mode. Compound 1 reveals short Ba – Ba contacts of 426.46(2) pm, whereas the Pb – Pb distance of 411.01(6) pm in 2 is larger than twice the van der Waals radius. structure Abstract. Monoclinic single crystals of Ba 2 (H 2 O)[µ 10 C 6 H 2 (COO) 4 ] ( 1 ) and Pb 2 (H 2 O)[µ 10 -C 6 H 2 (COO) 4 ]  H 2 O ( 2 ) have been obtained using the silica gel method. Space group C2/c (no. 15), Z = 4; 1 : a = 780.89(4), b = 1756.19(8), c = 914.80(5) pm,   = 114.512(5)°; 2 : a = 756.70(10), b = 1772.8(2), c = 890.2(2) pm,   = 113.590(10)°. There are two crystallographically independent M 2+ ions (M = Ba, Pb). M(1) is surrounded by eight carboxylate oxygen atoms and one water molecule forming a tricapped trigonal prism. M(2) is coordinated by ten carboxylate oxygen atoms in the shape of a tetracapped octahedron. The connection between the M(1) and M(2) polyhedra leads to infinite layers parallel to (010) which are linked by [C 6 H 2 (COO) 4 ] 4  anions to form a three-dimensional framework. The [C 6 H 2 (COO) 4 ] 4  anion adopts a µ 10 coordination mode. Compound 1 reveals short Ba  Ba contacts of 426.46(2) pm, whereas Pb  Pb of 411.01(6) pm in characterized. The closely packed three-dimensional shows layer-like separation between the anions and

Triclinic single crystals of Cu2[Cu(H2O)4][(CH2)4(NH3)2][C6H2(COO)4]2·4H2O have beenprepared in aqueous solution at 55 °C. Space group P-1 (no. 2), a = 799.73(7), b = 977.43(8),c = 1086.27(9) pm, α = 87.194(7), β = 84.679(7), γ = 74.744(6)°, V = 0.81540(12) nm3, Z = 1.There are two unique Cu2+ with CN 4+1 (Cu(1)) and CN 4+2 (Cu(2)), respectively. The Cu-Odistances range from 197.4(2) to 214.9(2) pm (Cu(1)) and 191.6(2) to 240.1(4) pm (Cu(2)).There is a short Cu(1)-Cu(1) contact of 267.02(6) pm. A three-dimensional coordinationpolymer with negative excess charge and channel-like voids extending parallel to [-110] ismade up by Cu2+ and [C6H2(COO)4]4-. These voids accomodate [(CH2)4(NH3)2]2+ and watermolecules, which are not coordinated to Cu2+. Thermoanalytical measurements in airindicated a step-wise loss of water of crystallization commencing at 63 °C, which is finishedat approx. 250 °C followed by an exothermic decomposition yielding CuO. The Cu(1) pairsshow anti-ferromagnetic coupling.

Colourless single crystals of BaC4O4 have been obtained from aqueous solution at 80 °C.BaC4O4 is stable in air up to 490 °C. BaCO3 is formed by further increase of temperature.BaC4O4 crystallizes in the tetragonal space group I4/mcm (nr. 140) with a=635.95(5), c=1240.77(13) pm, Z=4. Ba2+ is coordinated by eight oxygen atoms of the squarate dianions; Ba—O 276.1(1) pm. The coordination polyhedron is a distorted, square anti-prism. The squarate dianions occupy crystallographic mirror planes and posses approximately 4/mmm symmetry; C—C 145.7(5) and 146.5(5) pm, C—O 125.9(3) pm. A layer-like separationbetween the cations and anions exists with respect to the [001] direction.

Colorless single crystals of Cd-2[mu(8)-MTB]center dot 3H(2)O center dot DMF (1) were prepared in DMF/H2O solution [1: space group C2/c (no. 15) with a = 1821.30(6), b = 2175.08(6), c = 1269.87(4) pm, beta = 129.684(1)degrees]. The connection between the methane-p-benzoate tetraanions (MTB4-) and the Cd2+ cations leads to a three-dimensional framework with channels extending along [110] and [110] with openings of 670 pm x 360 pm. The channel-like voids accommodate water molecules and N,N-dimethylformamide (DMF) molecules not bound to Cd2+. Colorless single crystals of [Cd-4(2,2 '-bipy)(4)(mu(7)-MTB)(2)]center dot 7DMF (2) were prepared in DMF in the presence of 2,2 '-bipyridine [2: space group P1 (no. 2) with a = 1224.84(4), b = 1418.85(5), c = 2033.49(4) pm, alpha = 85.831(2)degrees, beta = 88.351(2)degrees, gamma = 68.261(1)degrees]. The coordination of MTB4- to Cd2+ results in infinite layers parallel to (001). The layers, not connected by any hydrogen bonds, contain small openings of about 320 pm x 340 pm.

Triclinic single crystals of Cu2(H2O)4[C4H4N2][C6H2(COO)4]·2H2O have been grown in anaqueous silica gel. Space group P-1 (Nr. 2), a = 723.94(7) pm, b = 813.38(14) pm, c = 931.0(2) pm, α = 74.24(2)°, β = 79.24(2)°, γ = 65.451(10)°, V = 0.47819(14) nm3, Z = 1. Cu2+ is coordinated in a distorted, octahedral manner by two water molecules, three oxygen atoms ofthe pyromellitate anions and one nitrogen atom of pyrazine (Cu—O 194.1(2)–229.3(3) pm;Cu–N 202.0(2) pm). The connection of Cu2+ and [C6H2(COO)4)]4− yields infinite strands,which are linked by pyrazine molecules to form a two-dimensional coordination polymer.Thermogravimetric analysis in air showed that the dehydrated compound was stable between175 and 248 °C. Further heating yielded CuO.

Two bis(oxalato)cuprate(II) hybrid salts, (C5H7N2)2[Cu(C2O4)2]·2H2O (1) and(C7H11N2)2[Cu(C2O4)2]·5H2O (2) (C5H7N2 = 3-aminopyridinium; C7H11N2 = 2-amino-4,6-dimethylpyridinium) have been synthesized and characterized by elemental and thermalanalyses, IR and UV-Vis spectroscopies, single-crystal X-ray diffraction, and SQUID magnetometry. The polymeric anionic motifs in the two salts are significantly different. In 1, stacking of [Cu(C2O4)2]2- units through axial Cu···O contacts (2.890 Å) yields straight Cu(II) chains, with a prolate CuO6 octahedron around Cu(II) ions, formed by two cis-chelated oxalate anions and two axial O-atoms of neighboring [Cu(C2O4)2]2- units. By contrast, in 2,stacking of [Cu(C2O4)2]2- units occurs via bis-bidentate oxalate groups, yielding zigzag Cu(II) chains with a distorted CuO6 coordination sphere. Thermal studies confirmed the presence of solvent water molecules in both salts. Magnetic studies revealed weak antiferromagnetic and weak ferromagnetic interactions between Cu(II) ions in 1 and 2, respectively.