Synthesis,characterization, thermal study,and crystal structure of a new layered alkaline earth metal sulfonate: Sr[C2H4(SO3)2]

A rare two-dimensional layered inorganic–organic hybrid material, strontium sulfonate Sr[C₂H₄(SO₃)₂] was synthesized by hydrothermal reaction of strontium chloride hexahydrate and ethane disulfonic acid at 160 °C. Single-crystal X-ray diffraction was utilized for structural determination. Data showed that the compound, crystallized in the monoclinic system and space group of C2/c. With cell parameters a = 8.3183(7) Å, b = 5.4416(5) Å and c = 14.9784(13) Å. The new material was extensively studied by DRIFT-infrared spectroscopy, thermogravimetric analysis, SEM and powder X-ray diffraction. Results show that the compound is thermally stable.     

Novel carbon diamond-like phases LA5, LA7 and LA8

In this work, the structure and properties of seven diamond-like carbon phases obtained by linking the graphene layers were calculated using DFT and PM3 methods. The LA5 (Cmca), LA7 (Cmcm), and LA8 (I4₁/amd) diamond-like phases were predicted and studied in this work for the first time. Values of the unit cell parameters of the predicted phases are: a = 4.337 Å, b = 5.024 Å, and c = 4.349 Å for LA5 phase; a = 4.942 Å, b = 4.808 Å, and c = 4.390 Å for LA7 phase; and a = 4.906 Å and c = 4.960 Å for LA8 phase. For these LA5, LA7, and LA8 phases, various structure characteristics, densities, cohesive energies, bulk moduli, electronic densities of states and X-ray patterns were calculated. The comparative analysis showed that the diamond-like phase properties depend on the extent of their structure deformation relative to the cubic diamond structure.     

Reversible ferroelectric phase transition of 1,4-diazabicyclo [2,2,2]octane N,N′-dioxide di(perchlorate)

1,4-Diazabicyclo [2,2,2]octane N,N′-dioxide di(perchlorate), C₆H₁₄N₂O₂^2 +·2ClO₄⁻, was synthesized and separated as colorless block crystals. Differential scanning calorimetry detected that this compound underwent a reversible phase transition at ca. 216 K with a hysteresis of 5.5 K width, which was also confirmed by dielectric measurements. Single crystal X-ray diffraction data suggested that there was a transition from a room temperature phase with the space group of P2₁/c (a = 6.815(7) Å, b = 12.644(13) Å, c = 8.676(9) Å, β = 101.466(15)°, V = 732.7(13) ų, Z = 4) to a low temperature one with a space group of P2₁ (a = 9.892(8) Å, b = 12.559(10) Å, c = 17.401(13) Å, β = 92.065(8)°, V = 2160(3) ų, Z = 2). Crystallographic analysis showed that it belonged to chiral space group P2₁ with ferroelectric behaviors, and a typical ferroelectric feature of electric hysteresis loop was obtained in the low temperature phase. The disorder-order transformation of H₂-Dabcodo^2 + cation and ClO₄⁻ anion as well as the change of hydrogen bonds may drive the phase transition.     

Synthesis of apatite structure based BiNaCa3(PO4)3OH and its application for condensation reaction

Mono, di and trivalent ions containing hydroxyapatite of the formula BiNaCa₃(PO₄)₃OH has been synthesized and the compound's catalytic activity in three component Biginelli condensation was studied. The compound was characterized by powder XRD, FT-IR, SEM and TGA/DTA techniques. The unit cell dimensions of the compound were determined to be a = 9.412(2) Å, C = 6.92(2) Å and the unit cell volume is 530.9 Å³. The substituted hydroxyapatite phase showed enhanced reactivity in the one pot synthesis of 3,4-dihydropyrimidin-2(1H)-one by Biginelli reaction and resulted in an increased yield of the product.     

Structure of a new bulk Ti5Al2C3 MAX phase produced by the topotactic transformation of Ti2AlC

Upon annealing cold-pressed Ti₂AlC, ?325 mesh powders, at 1500 °C for 8 h in argon, the resulting partially sintered sample contained 43(±2) wt.% of the layered ternary carbide Ti₅Al₂C₃. Herein, the X-ray powder diffraction pattern of Ti₅Al₂C₃ is reported for the first time and its structure and stoichiometry are confirmed through high-resolution transmission electron microscopy. This phase has a trigonal structure (space group P3m1) with a unit cell consisting of 3 formula units and cell parameters of a = 3.064 Å, c = 48.23 Å. The lattice parameters determined through first principles calculations agree reasonably well with the experimentally determined values. At 147.1 GPa, the calculated bulk modulus falls between the bulk moduli of Ti₂AlC and Ti₃AlC₂. The transformation from Ti₂AlC to Ti₅Al₂C₃ is topotactic.     

Synthesis,structure and fluorescence properties of a uranyl-2,5-pyridinedicarboxylic acid coordination polymer: The missing member of the UO22+-2,n-pyridinedicarboxylic series

A 3D uranium-pyridinedicarboxylate, compound (1) [UO₂(C₇H₃NO₄)], represents the final member of a series of materials incorporating a series of 2,n-pyridinedicarboxylic (pydc) acids (n = 3,4,5,6). The resulting crystal structure [FW = 419.13, monoclinic, P2₁/n, a = 9.0096(3) Å, b = 8.1371(2) Å, c = 11.6954(4) Å, V = 852.45 ų, Z = 4] was determined by single crystal X-ray diffraction and fluorescent properties were investigated. Additionally, the complete series of uranium-2,n-pydc materials was examined on a basis of fluorescent behaviors and architectural similarities.     

Palladium nanocrystals supported on photo-transformed C60 nanorods: Effect of crystal morphology and electron mobility on the electrocatalytic activity towards ethanol oxidation

We report on the synthesis and decoration of high-aspect-ratio crystalline C₆₀ nanorods (NRs) by functionalized palladium nanoparticles with an average size of 4.78 ± 0.66 nm. In their pristine form, C₆₀ NRs suffer from partial damage in the solution-based decoration process resulting in poor crystallinity. However, by modifying the NR surface via in situ photochemical transformation in the liquid state, we are able to prepare highly stable NRs that retain their crystalline structure during the decoration process. Our method thus opens up for the synthesis of highly crystalline nanocomposite hybrids comprising Pd nanoparticles and C₆₀ NRs. Bys measuring the electron mobility of different C₆₀ NRs, we relate both the effect of electron mobility and crystallinity to the final electrocatalytic performance of the synthesized hybrid structures. We show that the photo-transformed C₆₀ NRs exhibit highly advantageous properties for ethanol oxidation based on both a better crystallinity and a higher bulk conductivity. These findings give important information in the search for efficient catalyst support.     

Ionothermal synthesis and crystal structure of a new layered nickel(II) diphosphate,DRM-1

A new layered ammonium nickel(II) diphosphate, (NH₄)₂[Ni₃(P₂O₇)₂(H₂O)₂], has been synthesized ionothermally in the ionic liquid 1-butyl-3-methyl imidazolium bromide and characterized by powder X-ray diffraction, elemental analysis, scaning electron microscopy, thermogravimetry etc. The results of the characterization show that the crystal adopts the monoclinic space group P2₁/a with the lattice constants a = 9.23529(2) Å, b = 7.98489(2) Å, c = 9.40772(2) Å, β = 100.2608(2)° and Z = 2. Its structure consists of chains of cis- and trans-edge-sharing [NiO₆]-octahedra linked via [P₂O₇] units to form layers of [Ni₃(P₂O₇)₂(H₂O)₂]^2? in the ab plane. Adjacent layers are separated in the c-direction by ammonium ions.     

An inorganic–organic hybrid material with a novel oxometallic framework: Hydrothermal synthesis and characterization of [Zn3O3(C13H14N2)3]V6O15

A new hybrid material [Zn₃O₃(C₁₃H₁₄N₂)₃]V₆O₁₅ (1) with extended framework structure has been synthesized hydrothermally and characterized by vibrational spectroscopy, thermogravimetry and complete single crystal X-ray diffraction analysis. The compound has a complex three-dimensional covalent framework structure. It exhibits a fully oxidized novel oxometallic framework containing 10-membered {V₄ZnO₅} oxometalate rings and 4,4′-trimethylene dipyridine ligands (C₁₃H₁₄N₂) that connect pairs of crystallographically equivalent zinc atoms. The extended structure of 1 may also be viewed as containing a framework of corner-sharing {VO₄} and {ZnO₂N₂} polyhedra together with 4,4’-trimethylene dipyridine ligands linking zinc centers. The hybrid material is thermally stable up to 323 °C. It contains metal centers and coordination geometry that make it a potentially attractive model compound for investigating the structures of metallo-organic biomolecules by use of solid state NMR spectroscopic techniques. Crystal data for C₃₉H₄₂N₆O₁₈V₆Zn₃: monoclinicic P2₁, a = 10.9894(9) Å, b = 18.1493 (15) Å, c = 13.0903 (11) Å, β = 109.8880(10)°, V = 2455.1(4) Å³, Z = 2, D_calc. = 1.873 Mg/m³.     

New data on the thermal behavior of 14 Å tobermorite

The thermal behavior of two specimens of 14 Å tobermorite (plombièrite) was studied in situ at the GILDA beamline (ESRF, Grenoble, France). During dehydration, plombièrite shortens its basal spacing from 14 to 11 Å, through a progressive approaching of the complex structural modules characterizing its crystal structure. Upon heating, the 11 Å phase progressively contracts its c periodicity, with its d₀₀₂ varying from 11.7 to 11.3 Å. At ca. 300 °C, a 9.6 Å phase appears; it is stable up to ca. 700 °C. Above this temperature, it expands its basal spacing up to 10.2 Å, before transforming into wollastonite.Moreover, one specimen was heated at 150 °C for 4 h and the heated product, identified as 11 Å tobermorite through X-ray powder diffraction, was used to collect micro-Raman spectra. The heated product shows single chains, in contrast with the 11 Å natural specimens studied up to now in which double wollastonite-like chains occur.     

LiBa1.5[B5O8(OH)3]: A new 1-D metal borate chain constructed from B5O9(OH)36 − cluster units

A new mixed metal borate LiBa_1.5[B₅O₈(OH)₃] (1) has been hydrothermally synthesized and structurally characterized by FT-IR spectroscopy, powder X-ray diffraction, single crystal X-ray diffraction, and thermogravimetric analysis, respectively. 1 crystallizes in the monoclinic system, space group C2/c, a = 11.2839(7) Å, b = 7.3974(4) Å, c = 20.7151(13) Å, β = 103.392(6)°, V = 1682.10(17) ų and Z = 8. The structure consists of infinite one-dimensional (1-D) borate chains constructed from B₅O₉(OH)₃^6 − cluster units. These BO chains are further linked by the Ba^2 + and Li⁺ cations to form a 3-D framework.     

Structure and stability of carbon nitride under high pressure and high temperature up to 125 GPa and 3000 K

The crystal structure of carbon nitride under high pressure and temperature was investigated up to megabar pressures using graphitic C₃N₄ as a starting material. It transformed to an orthorhombic phase above 30 GPa and 1600 K, which has a similar unit cell parameters (a = 7.6251(19), b = 4.4904(8), and c = 4.0424(8) Å at 1 atm) to those of reported hydrogen-bearing carbon nitride phases such as C₂N₂(NH) and C₂N₂(CH₂). Although the C:N ratio of this orthorhombic phase was carefully determined to be 3:4, FT-IR analysis showed a strong possibility of hydrogen contamination both in the starting and recovered samples. These results suggest that in the studied wide pressure and temperature range, hydrogen-bearing carbon nitride favors the orthorhombic structure with a fundamental composition of C₂N₂X where NH, CH₂, and even potentially vacancies can be flexibly accommodated in the X site.     

Temperature-insensitive dielectric and piezoelectric properties in (1-x)K0.5Na0.5Nb0.997Cu0.0075O3-xSrZrO3 ceramics

Systematic investigation on phase transition, dielectric and piezoelectric properties of (1-x)K_0.5Na_0.5Nb_0.997Cu_0.0075O₃-xSrZrO₃ (x = 0, 0.03, 0.06, 0.09, 0.12, 0.15, abbreviated as KNNC-100xSZ) ceramics was carried out. Due to the coexistence of orthorhombic and tetragonal phase in a wide temperature range, a diffused polymorphic phase transition (PPT) region was achieved in KNNC with x ≥ 0.06. KNNC-12SZ ceramics exhibited high dielectric permittivity (∼1679), low dielectric loss (∼0.02) and small variation (Δe'/ε'_25 °C ≤ 15%) in dielectric permittivity from −78 °C to 237.3 °C. KNNC-6SZ ceramic possessed a high level of unipolar strain (∼0.15%) and maintained a smaller variation of ±12% under the corresponding electric field of 60 kV cm⁻¹ at 10 Hz from 25 °C to 175 °C. d₃₃^*, which was calculated according to the unipolar strain at 60 kV cm⁻¹, was 230 pm V⁻¹ and remained stable below 100 °C. Therefore, our work provided a new promising candidate for temperature-insensitive capacitors and piezoelectric actuators.     

Crystal and geometry-optimized structure,Hirshfeld surface analysis and spectroscopic studies of tetrachlorocuprate and nitrate salts of 1-(2-fluorophenyl)piperazine cations, (C10H15FN2)[CuCl4] (I) and (C10H14FN2)[NO3] (II)

Two new organic-inorganic hybrid materials, 1-(2-fluorophenyl)piperazine-1,4-diium tetrachlorocuprate, (C₁₀H₁₅FN₂)[CuCl₄] (I) and 1-(2-fluorophenyl)piperazin-4-ium nitrate, (C₁₀H₁₄FN₂)[NO₃] (II), have been synthesized by an acid/base reaction at room temperature in the presence of 1-(2-fluorophenyl)piperazine as an organic-structure directing agent and their structures were determined by single crystal X-ray diffraction. Compound (I), (C₁₀H₁₅FN₂)[CuCl₄], crystallizes in the monoclinic system and P2₁/c space group with a = 7.5253 (2), b = 20.6070 (7), c = 9.7281 (3) Å, β = 103.6730 (17)°, V = 1465.82 (8) Å³ with Z = 4. Full-matrix least-squares refinement converged at R = 0.037 and wR(F²) = 0.088. Compound (II), (C₁₀H₁₄FN₂)[NO₃], belongs to the monoclinic system, space group P2₁/c with the following parameters: a = 10.8034 (2), b = 7.5775 (1), c = 14.4670 (3) Å, β = 111.761 (2)°, V = 1099.91 (4) ų and Z = 4. The structure was refined to R = 0.044, wR(F²) = 0.136.In the structures of (I) and (II), the anionic and cationic entities are interconnected by means of set of hydrogen bonding contacts forming three-dimensional networks. Intermolecular interactions were investigated by Hirshfeld surfaces and the contacts of the four different chloride atoms were notably compared. The results of the optimized molecular structure are presented and compared with the experimental one. The Molecular Electrostatic Potential (MEP) maps and the HOMO and LUMO energy gap of both compounds were computed. The vibrational absorption bands were identified by infrared spectroscopy. Theory (DFT) calculations of normal mode frequencies are compared with experimental ones.     

Synthesis of 1,1′-ferrocene bis(carboxypyrazole) compounds and displacement of the pyrazole ligands

The reaction of 1,1′-ferrocenedicarbonyl chloride with pyrazole or 3,5-dimethyl pyrazole generates novel 1,1′-ferrocene bis(amide) compounds 1 and 2, respectively. The crystal structure of 1 shows that the pyrazole rings are essentially co-planar with each other and with the cyclopentadienyl rings. Attempts to use the complexes as a chelating ligand were unsuccessful. Instead, treatment of 1 or 2 with Mo(CO)₄(pip)₂, pip = piperidine, led to displacement of the pyrazole ligands and formation of the known amide compound, 1,1′-ferrocene bis carbonyl piperidine. Replacement of the pyrazole is ascribed to the weakness of the amide bond caused by the aromaticity of the pyrazole ring. Crystal data for C₁₈H₁₄FeN₄O₂ (1): monoclinic P2(1)/c, a = 13.3907(18) Å, b = 10.2112(14) Å, c = 11.3082(16) Å, β = 105.209(2)°, V = 1492.1(4) Å³, Z = 4.     

Chemical corrosion of basic refractories by cement kiln materials

The study of basic refractories corrosion by cement kiln materials was carried out with powder tests and coating tests at the typical temperature range of the sintered material in the transition zone and the sintering zone (1200–1450 °C). The tested basic refractories were magnesia-spinel (MSp) and magnesia–zirconia (MZ) refractory bricks. The industry cement kiln materials were rich of sulphur and chlorine. The microstructures of the as-delivered and tested samples were researched by XRD and SEM–EDS techniques. The new phases detected in the samples with MSp (with and without ZrO₂) bricks after tests at the temperature of 1200 °C were binary (C₁₂A₇ t_mp ? 1392 °C, CaZrO₃: t_mp ? 2345 °C)¹: and ternary (C₂AS: t_mp ? 1593 °C or C₃MS₂: t_dp ? 1573 °C) phases. After tests at the temperature of 1300 °C and higher, ternary phases of C₇A₃Z (t_mp ? 1550 °C) and CaZrO₃ and quaternary phases Q-C₂₀A₁₃M₃S₃ or C₆A₄(M,f)S (t_dp ? 1380 °C) were detected. The C₃A₃·CaSO₄ phase was formed in the samples after the corrosion tests performed up to the temperature of 1300 °C. The new phases formed in the sample with the MZ bricks were clinker phases (β-C₂S, C₃A and C₂(A,F)/C₄AF) and the C₇A₃Z phase.     

(CH3NH3)2[Ge(B4O9)]: An organically-templated chiral borogermanate with second-order nonlinear and ferroelectric properties

An organically-templated chiral borogermanate (CH₃NH₃)₂[Ge(B₄O₉)] (1), has been solvothermally synthesized and characterized by elemental analysis, IR, PXRD, TGA, single-crystal X-ray diffraction and UV–vis spectrum. It crystallized in the monoclinic space group C2 (No. 5) with a = 10.249(1) Å, b = 9.449(1) Å, c = 6.956(2) Å, β = 131.76(2)°, V = 502.43(19) Å³, Z = 2. The structure is constructed by alternate linkage of GeO₄ tetrahedra and B₄O₉ clusters to form a zeotype framework with diamond topology. Four intersecting channels with different sizes are observed. Large circular 10-ring channels are clearly extended along the [001] direction, 9-ring channels are running along the [101], [110], and [112] directions, respectively. Additionally, two pairs of the right- and left-handed channels couple together along the [100] and [010] directions, respectively. The preliminary investigations show that compound 1 exhibits second-harmonic generation (SHG) response and ferroelectric properties.     

Experimental determination of bulk modulus of 14 Å tobermorite using high pressure synchrotron X-ray diffraction

Using a diamond anvil cell, 14 Å tobermorite, a structural analogue of calcium silicate hydrates (C–S–H), was examined by high-pressure synchrotron X-ray diffraction up to 4.8 GPa under hydrostatic conditions. The bulk modulus of 14 Å tobermorite was calculated, K_o = 47 GPa. Comparison of the current results with previous high pressure studies on C–S–H(I) indicates that: (1) the compression behavior of the lattice parameters a and b of 14 Å tobermorite and C–S–H(I) are very similar, implying that both materials may have very similar Ca–O layers, and also implying that an introduction of structural defects into the Ca–O layers may not substantially change in-plane incompressibility of the ab plane of 14 Å tobermorite; and (2) the bulk modulus values of 14 Å tobermorite and C–S–H(I) are dominated by the incompressibility of the lattice parameter c, which is directly related to the interlayer spacing composed of dreierketten silicate chains, interlayer Ca, and water molecules.     

Relaxor behavior and ferroelectric properties of a new Ba4SmFe0.5Nb9.5O30 tungsten bronze ceramic

Unfilled tungsten bronze ceramics with a composition of Ba₄SmFe_0.5Nb_9.5O₃₀ were prepared by the conventional solid-state sintering method. The phase, microstructure, dielectric and ferroelectric properties were studied. Room temperature XRD results indicated that the ceramic occurs in the tetragonal space group P4bm phase with cell parameters of a=b=12.4712(2) Å and c=3.9430(2) Å. The temperature-dependent dielectric properties, XRD data and Raman spectra data indicated that BSFN ceramics exhibit no phase changes from 35 °C to 450 °C. Fitting of a Vogel-Fulcher relationship with an activated energy E_a of 0.11 eV indicates an unambiguous dielectric relaxor state near room temperature. Furthermore, the BSFN ceramics exhibited residual polarization and coercive field of 3.45 µC/cm² and 24.65 kV/cm, respectively.