Abstract The As-containing proto-owyheeite [Ag 2.26(07) Cu 0.14(01) Tl 0.13(03) Pb 9.40(06) Sb 10.96(07) As 0.38(02) S 28 , P 2 1 / n , a = 8.1696 (2) Å, b = 27.3377 (4) Å, c = 22.8584 (4) Å, β = 90.078 (2)°, V = 5105.15 (17) Å 3 ] and sardashtite [Ag 2.23(06) Cu 0.65(02) Pb 10.34(07) Sb 8.96(13) As 1.83(02) S 28 , P 2 1 / n , a = 8.2038 (3) Å, b = 27.1002 (10) Å, c = 22.7885 (9) Å, β = 90.1850 (10)°, V = 5066.4 (3) Å 3 ] crystallize as twofold superstructures (doubling of the a -axis with respect to a hypothetical basic structure), which are closely related to the structure of owyheeite. In contrast to owyheeite, which features systematic (approximate) cyclic twinning by 120° rotation about [100], proto-owyheite and sardashtite are twinned by pseudo-merohedry (reflection at [100] or equivalently [001]), which made structural elucidation significantly less troublesome.
Abstract A new member of the rare-earth magnesium pentaborate family, DyMgB 5 O 10 , was synthesized via solid-state reaction followed by flux growth in a K 2 Mo 3 O 10 melt. Single crystals up to 0.5 mm were obtained and characterized by SEM, EDX, DSC, and XRD techniques. The crystal structure was refined in the monoclinic space group P 2 1 / n , confirming that it belongs to the same structural family as other R MgB 5 O 10 compounds. The structure consists of alternating anionic borate layers built from [B 5 O 12 ] 3− clusters and cationic Dy–O–Mg layers. Dy 3+ ions are coordinated by ten oxygen atoms in distorted polyhedra, while Mg 2+ occupy edge-sharing octahedral dimers. Thermal analysis revealed incongruent melting with T onset ∼ 1,072 °C. DFT calculations gave an indirect band gap of ∼6.06 eV, indicating a wide-bandgap dielectric. Photoluminescence and X-ray induced luminescence spectra exhibit characteristic Dy 3+ intra-4 f transitions, with dominant blue ( 4 F 9 / 2 → 6 H 15 / 2 ) and yellow ( 4 F 9 / 2 → 6 H 13 / 2 ) emissions. The intense yellow emission reflects the low symmetry of the DyO 10 polyhedra. Characteristic luminescence under X-ray excitation confirms effective energy transfer from the borate matrix to Dy 3+ . The combination of high thermal stability, wide band gap, and favorable optical properties makes DyMgB 5 O 10 a promising candidate for phosphors and X-ray scintillators.
Abstract The crystal structure of Mg and Zr- substituted strontium-hexagallate/-aluminate Sr(Ga 12− x Al x )O 19 single crystals is investigated by combining single crystal diffraction and quantum mechanical modeling based on density functional theory (DFT). The crystal structure is solved within the magnetoplumbite structure type (space group P 6 3 / mmc , Z = 2). Moreover, a refinement is carried out to determine the Wyckoff sites occupied by the substituent atoms Mg and Zr, as well as the shared occupancy of Ga and Al in the Sr(Ga 12− x Al x )O 19 solid solution. Through DFT calculations, the formation energies for the introduction of Mg, Zr and Al into the structure are determined, thus revealing the energetically most preferred sites for these cations. Both methods show results which are in good agreement, thus corroborating each other and providing the basis for a deepened understanding of the material in question.
Abstract Solid solutions are an omnipresent class of materials in all kinds of solids, being of ionic, covalent or metallic nature. The present overview emphasizes selected solid solutions, covering these three bonding situations. The focus lies on mineral solid solutions that are important resources for functional materials, on the application of synthetic solid solutions on a large industrial scale (e.g., steel, brass, bronzes, glasses, color pigments), materials with special properties as well as selected examples from basic research where solid solutions play an important role for modifying materials properties.
Abstract Ga 2 Se 3 and Ga 2 Te 3 crystallize to the cubic zincblende structure, where 1/3 of the cation sites are vacant. Semiconductors with large concentrations of vacancies are actively studied due to their potential for application. In this article, the modulated structure in quenched Ga 2 Te 3 has been studied using single crystal X-ray diffraction data. Analysis of satellite reflections observed at q = (0.06, 0.06, 0.00) c revealed that the real structure is tetragonal and belongs to the superspace group I 4 ̅ $̅{4}$ m 2( α , 0, 0)0(0, α , 0)0. The structure is characterized by an occupational modulation caused by Ga vacancies, and accompanying displacement modulations of both Ga and Te atoms. The origin of the displacement modulations was discussed and attributed to the expanding motions around the Ga vacant sites. These motions are concave downward (toward − z ) along [110] c , while they are upward (toward + z ) along [−110].
Present study aims to understand the crystalline nature of Sb-2(S,Se)(3) thin films sequentially prepared using RF magnetron and subsequent hot wall deposition techniques. Post-deposition annealing was carried out at 250 degrees C. X-ray diffraction (XRD) and Rietveld refinement confirms the orthorhombic Pnma phase, with anisotropic lattice expansion upon selenium substitution with the lattice parameters a = 11.5 & Aring;, b = 3.9 & Aring;, and c = 11.35 & Aring;. Visualization of Electronic Structure and Analysis (VESTA) analysis was used to construct the crystal structure using the atomic coordinates for Sb, S and Se. Coordination numbers indicate each antimony atom surrounded by six sulfur and selenium atoms, forming Sb-S-6 and Sb-Se-6 octahedra. VESTA simulations from Fourier-transformed structure factors, revealed more directional anisotropy in electronic charge distribution across the (322), (213), and (103) crystallographic planes. The (103) plane exhibits strong charge localization along Sb-Se bonds, while the (322) plane shows smoother electron density with minimal trapping. The mapping revealed a high concentration of charges with the presence of few vacancies at a spatial resolution of 0.5 & Aring; across each lattice planes. TEM confirms the orthorhombic phase formation, fine grains and crystalline periodicity. EDX confirms the uniform Sb, S, and Se distribution attributing to composition of the films.
Abstract Novel phases RE 11 Co 4 In 9 ( RE = Pr, Nd, Sm, Tm, Lu) were obtained by arc-melting of the elements in an argon atmosphere followed by annealing at T = 870 K for 1,500 h in evacuated and sealed silica ampoules. All samples were characterized through their powder X-ray diffraction patterns and metallographic and quantitative phase analyses. The structure of the Pr 11 Co 4 In 9 compound was refined from powder X-ray diffraction patterns using the FullProf program package. The compound crystallizes in Nd 11 Pd 4 In 9 type structure (orthorhombic space group Cmmm , Z = 2; a = 14.801(10); b = 22.119(14); c = 3.746(2) Å) and belongs to a large family of two-layer structures (with layers perpendicular to the short unit cell axis) based on the intergrowth of AlB 2 - and CsCl-type related slabs. Pr 11 Co 4 In 9 - together with the Mo 2 FeB 2 , Mn 2 AlB 2 , o-La 2 Ni 2 In, Lu 5 Ni 2 In 4 types structure, in which the ternary indides crystallize – forms a homologous series RE m+n T 2n X m , where m is the number of REX (CsCl type) slabs and n the number of RET 2 (AlB 2 type) slabs ( T = Co, X = In). For Pr 11 Co 4 In 9 the values are m = 18, n = 4. The isostructural compounds were obtained with Nd, Sm, Tm, Lu and complete the series of RE 11 Co 4 In 9 ( RE = Sc, Y, Gd, Tb, Dy, Ho, Er) compounds. The electronic structure calculations were performed by means of the TB-LMTO-ASA program indicating a covalent interaction between In1–In1 atoms and metallic bonding between other In, Pr and Co atoms.
The series of cadmium-rich rare earth intermetallics REPd2Cd20 (RE = Ca, Y, La, Ce, Nd, Eu-Lu) was synthesized by high-temperature reactions of the elements in sealed tantalum ampoules. Single crystals were grown by slow cooling of the reaction products. All REPd2Cd20 phases were characterized through their Guinier powder patterns. The structure of GdPd2Cd20 was refined from single crystal X-ray diffractometer data: CeCr2Al20 type, Fd (3) over tildem, a = 1,560.28(2) pm, wR = 0.0521, 356 F-2 values and 17 variables. The REPd2 substructure has the topology of the cubic Laves phase MgCu2. The rare earth and palladium atoms have 16 and 12 cadmium neighbors forming Frank-Kasper type polyhedra, respectively. Temperature dependent magnetic susceptibility measurements show Pauli paramagnetism for YPd2Cd20 and Curie-Weiss paramagnetism for the remaining rare earth compounds. EuPd2Cd20, GdPd2Cd20, TbPd2Cd20 and DyPd2Cd20 show antiferromagnetic ordering below the Neel temperatures of 8.9(1) (RE = Eu), 15.6(1) (RE = Gd), 9.5(3) K (RE = Tb) and 7.4(1) K (RE = Dy), respectively. TbPd2Cd20 and DyPd2Cd20 exhibit metamagnetic transitions at critical fields of 12(1) and 6.9(2) kOe, respectively. EuPd2Cd20 has a stable divalent ground state. The Eu-151 Mossbauer spectrum at 78 K shows an isomer shift of -10.58(2) mm s(-1).
Abstract A new organically templated hybrid organo-inorganic compound, (C 4 H 12 N 2 )SO 4 ⋅3H 2 SeO 3 , was prepared during systematic studies of sulfate co-crystals with selenious acid. The new compound crystallizes in a non-centrosymmetric space group P 2 1 ( a = 6.2876(2) Å, b = 17.9296(6) Å, c = 7.2701(3) Å, β = 106.979(4)°, R 1 = 0.027) and exhibits a weak SHG activity. The new compound belongs to a rapidly developing family of hydrogen-bonded architectures formed by selenious acid co-crystals. The crystal structure corresponds to a pseudo-layered hydrogen-bonded framework with alternating organic and inorganic “slabs” linked by hydrogen bonds.
Abstract Three novel phosphor/thiophosphor-amides, [(5-CH 3 )- 2 Py-NH] 2 [C 6 H 11 (CH 3 )N]P(X) (X = O ( 1 ) and S ( 2 )) and [(5-CH 3 )- 2 Py-NH]P(O)[OCH 2 C(CH 3 ) 2 CH 2 O] ( 3 ), were synthesized and characterized by FT-IR and 1 H/ 13 C/ 31 P-NMR spectroscopy. The structures of 1 and 3 were determined by using single-crystal X-ray diffraction (SC-XRD) crystallography which reveals both compounds to crystallize in monoclinic space groups ( P 2 1 / c and P 2 1 / n , respectively). A crystal packing analysis shows that neighbouring molecules are connected together via N–H⋯O═P hydrogen bonds forming one-dimensional chains. A Hirshfeld surface analysis indicates that crystal packing is dominated by H⋯H, H⋯O/O⋯H, H⋯C/C⋯H, and H⋯N/N⋯H contacts, with O⋯H/H⋯O interactions including the classical N–H⋯O═P hydrogen bonds being particularly favored. Phosphor/thiophosphor-amide derivatives are emerging as promising scaffolds for targeting key enzymes of acetylcholinesterase (1EEA, 5FPP) and urease (2UBP, 4GY7). Molecular docking revealed favorable binding affinities (up to −10.3 kcal/mol for 1 with 1EEA), with compounds 1 and 2 generally exhibiting stronger predicted interactions than compound 3 . Key stabilizing interactions involve phosphoryl/thiophosphoryl groups and pyridine rings. Redocking of co-crystallized ligands with RMSD assessment confirmed the reliability of the docking protocol. While these results do not provide definitive evidence of inhibitory potency, they support further computational refinement and experimental evaluation, highlighting the potential of these derivatives as enzyme-interacting agents with biomedical relevance.
The structure of La x Sr 1-x TiO 3 single-phase perovskites (0.10 ≤ x ≤ 0.30) was studied using synchrotron X-ray Powder Diffraction for Rietveld and Pair Distribution Function analysis. Electron Spin Resonance and X-ray Raman Scattering Spectroscopy confirmed that Sr substitution by La is charge compensated via electron injection into the conduction band. High-resolution diffraction (110–490 K) revealed phase transitions to a tetragonal phase with antiferrodistortive tilting ( a 0 a 0 c - , in Glazer notation). Fitting the Ginzburg-Landau mean field equation indicated a transition regime between second-order and tricritical. The critical temperature (T C ) and tilt order parameter ( Φ 0 ) increase with La content up to x = 0.20, then decrease at x = 0.30. This non-monotonic behavior reflects an emerging local symmetry lowering toward Cmcm , supported by increased octahedral tilting and Bond Valence Sum analysis. The enhanced tilting offsets compensate for reduced thermal contraction of Ti 3+ -rich TiO 6 octahedra below T C .
We present here the syntheses, crystal structure, and characterizations of a new mixed metal phosphatoantimonate, with the name of Li 5 CuSb(PO 4 ) 4 (LCSP), which was synthesized by traditional solid-state method for the first time. According to the single-crystal structure analysis, the title compound crystallizes in the triclinic system with space group P 1 ‾ $P\overline{1}$ , which features a novel 2D frameworks formed by the corner sharing PO 4 groups, SbO 6 octahedra, and CuO 4 pseudo plane tetrahedra. The anionic [CuSb(PO 4 ) 4 ] 5− cupro-stibio-phosphate layer is composed of two alternate chains of [Cu(PO 4 ) 2 ] 4− and [Sb(PO 4 ) 2 ] − further connected via the linkages of P–O–Sb. Characterizations including thermal and optical analyses have also been performed. The most impressive thing about the title compound is its layer structure and high Li content in its formula. AC impedance measurements have been carried out to study its conductivity. The representative impedance spectra of 250 °C, 300 °C and 350 °C indicated well-separated bulk arch and grain boundary arc in frequency domain. Linear fitting of arrhenius plot of bulk and GB conductivity showed that bulk activation energy was 1.00 ± 0.02 eV while GB activation energy was 1.30 ± 0.04 eV.
Abstract Hydrothermally synthesized selenite chloride Pb 3 Cu 2 (SeO 3 ) 4 Cl 2 crystallizes in orthorhombic space group Pnma with a = 14.9374(3), b = 19.5578(3), c = 5.23070(10) Å, V = 1,528.11(5) Å 3 , Z = 4, and shows a novel structure type. Its crystal structure contains CuO 4 Cl tetragonal pyramids joint together via Cl apical vertices in pairs. Triangular selenate groups share oxygen atoms with the square planes of copper pyramids, forming chains parallel to the short c axis of the unit cell. The lone pairs of the Se 4+ ions are directed in the opposite side of three oxygen ligands in selenium coordination, contributing to the linkage of neighboring anionic [Cu 2 Cl(SeO 3 ) 4 ] 5− ∞ chains into layers, which alternate with [Pb 3 Cl] 5+ cationic layers in the a axis direction. Topological correlations between the title crystal structure and that of mineral sarrabusite, Pb 5 Cu(SeO 3 ) 4 Cl 4 are discussed. The low-dimensional behavior of Pb 3 Cu 2 (SeO 3 ) 4 Cl 2 is demonstrated by the data from magnetization and heat capacity measurements.
The novel phase Ca(VO)F(PO4)& centerdot;H2O was prepared by hydrothermal synthesis at a temperature of 230 degrees C and a pressure of 100 atm. Its crystal structure was determined using single-crystal X-ray diffraction, and refined as an inversion twin against the F 2 data. The compound crystallizes in the monoclinic space group P21, with unit-cell parameters a = 6.3198(8), b = 6.3230(7), c = 6.5826(10) & Aring;, beta = 105.68(2)degrees, and Z = 2. The structure is based on alternating corner sharing VO5F octahedra and PO4 tetrahedra to form layers of four-connected nets. The negatively charged vanadyl-phosphate [VO(PO4)]- infinity layers alternate along the [001] and [010] directions with Ca salt component [CaF(H2O)]+ that ensures electroneutrality of the compound. The water molecules participate in the coordination of Ca atoms, and serve as donors of bifurcated hydrogen bonds. The compound is a new structural representative of the topology derived from the VOPO4 & centerdot;2H2O - a mixed protonic-electronic conductor. The CaF2 salt incorporation in the interlayer space changes the electronic state of V5+ to V4+ and reduces the structure symmetry from tetragonal to monoclinic. The Ca(VO)F(PO4)& centerdot;H2O is discussed as a new member in the sincosite family of natural and synthetic compounds, which crystallize as polymorphic modifications.
Pseudosymmetry in organic molecular crystals has been an important area of study for decades. One particular type of pseudosymmetry, recently identified by us, is characterized as racemic mimicry. Here, we report the first example of a double racemic mimic crystallization pathway , demonstrated in the organic salt 1-phenylethan-1-aminium naphthalene-1-carboxylate (Ph-1NA). The racemic form, ENOBOZ, crystallizes in the triclinic space group P 1 $\boldsymbol{P}{\mathbf{1}}$ , with Z ' = 2, while the enantiopure form, BIFTIW, crystallizes in P1 with Z ' = 4. The two structures have nearly identical unit cell parameters. Despite their different space group symmetries and chiral compositions, both structures exhibit nearly identical hydrogen-bonded tetrameric motifs (R4 4 (12) and R4 2(8)) as well as closely related intermolecular packing arrangements. Analysis of the published structures shows that the two tetramers of ENOBOZ are related by an inversion center, whereas the corresponding clusters in BIFTIW are related by a pseudo-inversion center, with similar conformations of the independent cations in both forms. This pseudosymmetry establishes BIFTIW as a mimic of ENOBOZ, extending the racemic mimic concept to higher Z ' ratios (4:2) for the first time. The discovery of this double racemic mimic in the Cambridge Structural Database highlights the persistence of supramolecular motifs across distinct crystallization pathways and expands our understanding of pseudosymmetry, polymorphism, and the design principles governing supramolecular crystal engineering.
Accurate crystal structure determination requires reliable models of how atoms scatter X-rays and electrons. While quantum crystallographic methods such as Hirshfeld atom refinement (HAR) markedly improve upon the widely used Independent Atom Model (IAM) by incorporating ab initio electron densities, their reliance on numerical real-space grids imposes a significant computational bottleneck. Here, we present a density-fitting-based refinement scheme that addresses this limitation by expanding the molecular electron density via the Resolution-of-the-Identity (RI) approach into atom-centred Gaussian contributions. This enables fully analytic evaluation of aspherical X-ray and electron scattering factors, eliminating the need for real-space grids or reference atoms entirely. Benchmark refinements on a diverse set of small-molecule crystals within Olex2/NoSpherA2 demonstrate that the RI-based model reproduces R values, residual electron density, X-H bond lengths, and anisotropic displacement parameters on par with HAR, while offering substantially improved computational efficiency. This is most prominent particularly at high diffraction resolution and for larger asymmetric units.
Novel phases RE 11Co4In9 (RE = Pr, Nd, Sm, Tm, Lu) were obtained by arc-melting of the elements in an argon atmosphere followed by annealing at T = 870 K for 1,500 h in evacuated and sealed silica ampoules. All samples were characterized through their powder X-ray diffraction patterns and metallographic and quantitative phase analyses. The structure of the Pr11Co4In9 compound was refined from powder X-ray diffraction patterns using the FullProf program package. The compound crystallizes in Nd11Pd4In9 type structure (orthorhombic space group Cmmm, Z = 2; a = 14.801(10); b = 22.119(14); c = 3.746(2) & Aring;) and belongs to a large family of two-layer structures (with layers perpendicular to the short unit cell axis) based on the intergrowth of AlB2- and CsCl-type related slabs. Pr11Co4In9 - together with the Mo2FeB2, Mn2AlB2, o-La2Ni2In, Lu5Ni2In4 types structure, in which the ternary indides crystallize - forms a homologous series RE m+n T 2n X m, where m is the number of REX (CsCl type) slabs and n the number of RET 2 (AlB2 type) slabs (T = Co, X = In). For Pr11Co4In9 the values are m = 18, n = 4. The isostructural compounds were obtained with Nd, Sm, Tm, Lu and complete the series of RE 11Co4In9 (RE = Sc, Y, Gd, Tb, Dy, Ho, Er) compounds. The electronic structure calculations were performed by means of the TB-LMTO-ASA program indicating a covalent interaction between In1-In1 atoms and metallic bonding between other In, Pr and Co atoms.
