Orthorhombic Space Group Pnma Research Articles

La3NSe3 and La3PSe3: Two Isostoichiometric, but not Isostructural Lanthanum‐Selenide Derivatives

AbstractThe two non‐isostructural lanthanum pnictogenide selenides La3NSe3 and La3PSe3 are formed by oxidizing lanthanum metal with sodium azide (NaN3) in the presence of selenium and an excess of iodine for eight days at 850 °C and by reacting the two binary compounds lanthanum sesquiselenide (La2Se3) and lanthanum monophosphide (LaP) for four days at 900 °C in torch‐sealed glassy silica ampoules. La3NSe3 crystallizes with the well‐known Sm3NS3‐type structure in the orthorhombic space group Pnma with the lattice parameters a=1278.56(8) pm, b=424.18(3) pm, c=1358.73(9) pm, while La3PSe3 adopts the cubic Th3P4‐type structure in the space group with the lattice parameter a=901.42(6) pm, both for Z=4. It features one crystallographically distinct cationic La3+ site and a mixed anionic site with both P3− and Se2− anions sharing the same crystallographic position in its crystal structure. In contrast, the crystal structure of La3NSe3 is comprised of three different La3+ cations with one N3− and three distinct Se2− anions. The key structural elements are N3− centered (La3+)4 tetrahedra connected via vertices to form one‐dimensionally infinite chains (t=terminal, v=vertex‐sharing). The comparatively large La3+ cation adopts coordination numbers of six (1×) and seven (2×) in La3NSe3, whereas in La3PSe3, the coordination number of the single cation site is eight.

Low temperature magnetic properties of Gd doped CaMnO3

The Gadolinium (Gd) doped CaMnO 3 or Ca 0.7 Gd 0.3 MnO 3 (CGMO), structural and magnetic behavior were investigated through the X-ray diffraction and DC magnetization measurements. The high quality CGMO polycrystalline were prepared through the multiple heat treatment of solid-state reaction method. The X-ray diffraction measurement confirms the formation of single-phase with orthorhombic structure and Pnma space group. Scanning electron microscopy study reveals the surface morphology and average grain size about 2 μm. Rietveld refinement techniques were used to obtain the room temperature (RT) atomic parameters. The obtained atomic parameters of CGMO are a = 5.3465(4) Å, b = 7.5001 (5) Å and c = 5.3184 (4) Å are well matching with CaMnO 3 . Temperature-dependent (4–300 K) magnetic susceptibility (M)T measurements were carried out on CGMO at 500 Oe. Low-temperature magnetic susceptibility (ZFC and FC curves) confirms the magnetic transition i.e, paramagnetic to antiferromagnetic phase (T N ) at 67 K, and surprisingly below 10 K magnetic moments are increasing, it may be due to the formation of weak ferromagnetic ordering. Curie Weiss fitting was carried out on low-temperature inverse susceptibility of field cooled curve which shows hump around 67 K and below 10 K. From the Curie-Weiss fitting paramagnetic curie constant θp ∼ -72 K extracted, which is a clear indication of the formation of antiferromagnetic ordering and below 10 K weak ferromagnetic interaction.

Experimental and Theoretical Study on the Nonmagnetic Li/Mg Cosubstitution in the Gd5-x(Li/Mg)xGe4 (x = 1.04, 1.17, 1.53) System.

Three Li- and Mg-cosubstituted compounds in the Gd5-x(Li/Mg)xGe4 (x = 1.04(2), 1.17(2), 1.53(2)) system have been successfully prepared by conventional high-temperature reactions. According to powder and single-crystal X-ray diffraction analyses, all three compounds adopt a Gd5Si4-type phase with the orthorhombic Pnma space group (Pearson code oP16, Z = 4) and six crystallographically independent atomic sites. The crystal structure can be described as a combination of two-dimensional Mo2FeB2-type ∞2[Gd2(Li/Mg)Ge2] layers and [Ge2] dimers. Interestingly, as 64% of Li and 26% of Gd at the RE3 and RE2 sites, respectively, were exclusively substituted by Mg in Gd3.47(1)Li0.36(2)Mg1.17(3)Ge4, the lattice parameter b was selectively shortened as a result of the RE3-Ge1 bond shrinkage in comparison to that in Gd4LiGe4, while lattice parameters a and c remained nearly intact. A series of theoretical calculations using the tight-binding linear muffin-tin orbital (TB-LMTO) method indicated that the reduction of the particular RE3-Ge1 bond distance in the title compounds could also be explained by an optimization of bonding based on the corresponding RE3-Ge1 crystal orbital Hamilton population (COHP) curve. Moreover, the specific site preference of Mg for the RE3 site was supported by both size-factor as well as electronic-factor criteria on the basis of the smallest atomic size and the highest electronegativity of Mg among the three cations. Therefore, the overall electronic structure was further interrogated by a density of states (DOS) analysis. The influence of nonmagnetic Li/Mg cosubstitution for the magnetic Gd atoms in the title Gd5-x(Li/Mg)xGe4 system on the magnetic characteristics was also thoroughly studied by isofield magnetization at 100 Oe and 10 kOe and isothermal magnetization measurements at 4 K using two of the title compounds: Gd3.83(1)Li0.48Mg0.69(3)Ge4 and Gd3.47(1)Li0.36(2)Mg1.17(3)Ge4.

Calcium Substitution in Rare‐earth Metal Germanides with the Gd 5 Si 4 Type Structure

An extended series of rare-earth metal calcium germanides have been synthesized and structurally characterized. The compounds have the general formula RE5−xCaxGe4 (1.5<x<3.6; RE=rare-earth metal; Ce, Nd, Sm, Tb−Lu) and their structures have been established from single-crystal X-ray diffraction methods. They crystallize with the Gd5Si4-type in the orthorhombic space group Pnma (No. 62; Z=4; Pearson symbol oP36), where the germanium atoms are interconnected into two kinds of Ge2-dimers, formally [Ge2]6−. These studies show that Ca can be successfully incorporated into the host RE5Ge4 structure, whereby trivalent rare-earth metal atoms can be substituted by divalent calcium atoms. Rare-earth metal and calcium atoms are arranged in distorted trigonal prisms and cubes, centered by either Ge or Ca atoms. On one of the metal sites, the substitution is preferential and in 9 out of the 10 refined structures, the Wyckoff site 4c is found almost exclusively occupied by Ca. On the other two metal sites the substitution patterns appear to be governed by the mismatch between the size of the RE3+ and Ca2+ ions. This work further demonstrates the ability for the Gd5Si4 structure type to accommodate the substitution of a non-magnetic element while maintaining the global structural integrity.

Quaternary Selenides EuLnCuSe3: Synthesis, Structures, Properties and In Silico Studies.

In this work, we report on the synthesis, in-depth crystal structure studies as well as optical and magnetic properties of newly synthesized heterometallic quaternary selenides of the Eu+2Ln+3Cu+1Se3 composition. Crystal structures of the obtained compounds were refined by the derivative difference minimization (DDM) method from the powder X-ray diffraction data. The structures are found to belong to orthorhombic space groups Pnma (structure type Ba2MnS3 for EuLaCuSe3 and structure type Eu2CuS3 for EuLnCuSe3, where Ln = Sm, Gd, Tb, Dy, Ho and Y) and Cmcm (structure type KZrCuS3 for EuLnCuSe3, where Ln = Tm, Yb and Lu). Space groups Pnma and Cmcm were delimited based on the tolerance factor t’, and vibrational spectroscopy additionally confirmed the formation of three structural types. With a decrease in the ionic radius of Ln3+ in the reported structures, the distortion of the (LnCuSe3) layers decreases, and a gradual formation of the more symmetric structure occurs in the sequence Ba2MnS3 → Eu2CuS3 → KZrCuS3. According to magnetic studies, compounds EuLnCuSe3 (Ln = Tb, Dy, Ho and Tm) each exhibit ferrimagnetic properties with transition temperatures ranging from 4.7 to 6.3 K. A negative magnetization effect is observed for compound EuHoCuSe3 at temperatures below 4.8 K. The magnetic properties of the discussed selenides and isostructural sulfides were compared. The direct optical band gaps for EuLnCuSe3, subtracted from the corresponding diffuse reflectance spectra, were found to be 1.87–2.09 eV. Deviation between experimental and calculated band gaps is ascribed to lower d states of Eu2+ in the crystal field of EuLnCuSe3, while anomalous narrowing of the band gap of EuYbCuSe3 is explained by the low-lying charge-transfer state. Ab initio calculations of the crystal structures, elastic properties and phonon spectra of the reported compounds were performed.

Crystal Structures of Hexafluoridoantimonate(V) Salts of d‐block Metals in Oxidation State +2

AbstractThe crystal structures of the M(SbF6)2 salts (M=Cu, Pd) are isotypic (Type I). They crystallize in the triclinic space group , Z=1 at 150 K. M2+ cations lying in the same plane are connected via SbF6 units forming slabs. There are only van der Waals contacts of fluorine atoms between the adjacent slabs. Salts of M(SbF6)2 (M=Fe, Co, Zn) crystallize differently (Type II; space group , Z=2 at 150 K). Their crystal structures are composed of M2+ cations interconnected by [SbF6]− anions – thus forming a three‐dimensional framework. The crystal structure of Fe(SbF6)2, determined at 240 K, is currently the only representative of the Type III. The main feature of this type is also a three‐dimensional framework consisting of M2+ cations and [SbF6]− anions. However, the mode of their association differs from that observed in Type II. The crystal structures of CuFSbF6 (orthorhombic space group Imma, Z=4 at 150 K) and AgFSbF6 (orthorhombic space group Pnma, Z=4 at 150 K) are not isotypic. The crystal structures of the by‐products H3ONi(SbF6)3 (orthorhombic space group Pnma, Z=4 at 150 K) and (O2)2Ag6CuF5(SbF6)11 ⋅ 2HF (triclinic space group , Z=1 at 150 K) were determined. In the latter, HF is directly attached to an Ag(II) via a fluorine atom.

Ion-bearing stairs: alkali metal complexes of 1,2-diaza-4-phospholides.

In this work, eight alkali metal complexes with 1,2-diaza-4-phospholide ligands were prepared and characterized by X-ray single-crystal structural analysis and NMR spectroscopy. Their structures showed varied coordination motifs: (i) a dimeric 1,2-diaza-4-phospholide lithium complex with exo-bidentate bridging coordination (4) consists of two lithium atoms that are linked via two μ2-bridging, κN,κN'-coordinated ligands; (ii) the polymeric chain 1,2-diaza-4-phospholide potassium complex (5) showed an ion-bearing stair-shaped chain structure running through axis a, where the steps are η2 interactions, and there is a transition platform between every two stairs; (iii) the polymeric chain 1,2-diaza-4-phospholide potassium complex (6) also presented a polymeric chain structure in the solid state but displayed a head-to-tail arrangement of two 1,2-diaza-4-phospholides; (iv) in comparison to 6, the 1,2-diaza-4-phospholide sodium complex (7) displayed a tetrameric structure, in which the sodium ions are arranged in a distorted tetrahedral fashion and each of them occupies a vertex of the tetrahedron; (v) the polymeric chain 1,2-diaza-4-phospholide potassium complex (8) presented a solvent-free chain structure, in which potassium ions each is η5-bonded by two 1,2-diaza-4-phospholides and η2-coordinated by another, consisting of a stair-shaped chain structure running through axis a but without significant intermolecular contacts between the adjacent stairs in comparison to that of 5; (vi) the polymeric chain 1,2-diaza-4-phospholide sodium complex (9) presented a solvent-free chain structure, in which sodium ions each is η1(N),η2(N,N),η1(P)-bonded by three 1,2-diaza-4-phospholides, consisting of a chain structure running through axis a; and (vii) the treatment complex 8 with elemental sulphur or selenium in the presence of crown ether gave rare thiophosphonato potassium [η3(S,P,S)-3,5-tBu2dp-(μ-K)(S2)([18]crown-6)] (10) or a selenophosphonato potassium [η3(Se,P,Se)-3,5-tBu2dp-(μ-K)(Se2)([18]crown-6)] (11). Both of the complexes crystallized in the orthorhombic space group Pnma as pale-yellow (or red) crystals. The X-ray diffraction analysis revealed 10 or 11 as a terminal complex with the η1,η1-X,X-coordination mode (X = S and Se). The 1H DOSY NMR spectroscopy study of the species 8 in DMSO-d6 suggested that polymeric complexes (4-9) in the solid state should dissociate into the related monomers in the solutions when the donor solvents were used.

A-Site Cation Size Effect on Structure and Magnetic Properties of Sm(Eu,Gd)Cr0.2Mn0.2Fe0.2Co0.2Ni0.2O3 High-Entropy Solid Solutions.

Three high-entropy Sm(Eu,Gd)Cr0.2Mn0.2Fe0.2Co0.2Ni0.2O3 perovskite solid solutions were synthesized using the usual ceramic technology. The XRD investigation at room temperature established a single-phase perovskite product. The Rietveld refinement with the FullProf computer program in the frame of the orthorhombic Pnma (No 62) space group was realized. Along with a decrease in the V unit cell volume from ~224.33 Å3 for the Sm-based sample down to ~221.52 Å3 for the Gd-based sample, an opposite tendency was observed for the unit cell parameters as the ordinal number of the rare-earth cation increased. The average grain size was in the range of 5–8 μm. Field magnetization was measured up to 30 kOe at 50 K and 300 K. The law of approach to saturation was used to determine the Ms spontaneous magnetization that nonlinearly increased from ~1.89 emu/g (Sm) up to ~17.49 emu/g (Gd) and from ~0.59 emu/g (Sm) up to ~3.16 emu/g (Gd) at 50 K and 300 K, respectively. The Mr residual magnetization and Hc coercive force were also determined, while the SQR loop squareness, k magnetic crystallographic anisotropy coefficient, and Ha anisotropy field were calculated. Temperature magnetization was measured in a field of 30 kOe. ZFC and FC magnetization curves were fixed in a field of 100 Oe. It was discovered that the Tmo magnetic ordering temperature downward-curve decreased from ~137.98 K (Sm) down to ~133.99 K (Gd). The spin glass state with ferromagnetic nanoinclusions for all the samples was observed. The <D> average and Dmax maximum diameter of ferromagnetic nanoinclusions were calculated and they were in the range of 40–50 nm and 160–180 nm, respectively. The mechanism of magnetic state formation is discussed in terms of the effects of the A-site cation size and B-site poly-substitution on the indirect superexchange interactions.

Synthesis, structures and physical properties of new transition metal fluoroselenides Ba3F2MSe3 (M = Zn, Cd)

Two new transition metal fluoroselenides Ba3F2MSe3 (M ​= ​Zn, Cd) have been successfully synthesized by solid-state reaction. Both compounds adopt the same crystal structure with orthorhombic space group Pnma (No. 62), consisting of an infinite corner-sharing [MSe3]4- anion chain separated by [Ba3F2]4+ cationic chain of the fluorite type. Ba3F2ZnSe3 and Ba3F2CdSe3 show paramagnetic behaviors from 1.8 to 300 ​K due to the absence of magnetic transition metals. Their Debye temperatures are 170 ​K and 163 ​K, respectively, determined from the low-temperature specific heat measurements. The diffuse-reflectance spectroscopy measurements reveal that these new compounds are semiconductors with optical band gaps of 1.80 ​eV and 1.69 ​eV for Ba3F2ZnSe3 and Ba3F2CdSe3, which are consistent with the band gaps obtained from the first-principle calculations.

Synthesis of Hydrated Ternary Lanthanide-Containing Chlorides Exhibiting X-ray Scintillation and Luminescence.

A series of new ternary lanthanide-based chlorides, Cs2EuCl5(H2O)10, Cs7LnCl10(H2O)8 (Ln = Gd or Ho), Cs10Tb2Cl17(H2O)14(H3O), Cs2DyCl5(H2O)6, Cs8Er3Cl17(H2O)25, and Cs5Ln2Cl11(H2O)17 (Ln = Y, Lu, or Yb), were prepared as single crystals via a facile solution route. The compounds with compositions of Cs7LnCl10(H2O)8 (Ln = Gd or Ho) and Cs5Ln2Cl11(H2O)17 (Ln = Y, Lu, or Yb) crystallize in a monoclinic crystal system in space groups C2 and P21/c, respectively, whereas Cs2EuCl5(H2O)10, Cs10Tb2Cl17(H2O)14(H3O), and Cs8Er3Cl17(H2O)25 crystallize in orthorhombic space groups Pbcm, Pnma, and P212121, respectively. Cs2DyCl5(H2O)6 crystallizes with triclinic symmetry in space group P1̅. All of these compounds exhibit complex three-dimensional structures built of isolated lanthanide polyhedral units that are linked together by extensive hydrogen bonds. Cs2EuCl5(H2O)10 and Cs10Tb2Cl17(H2O)14(H3O) luminesce upon irradiation with 375 nm ultraviolet light, emitting intense orange-red and green color, respectively, and Cs10Tb2Cl17(H2O)14(H3O) scintillates when exposed to X-rays. Radioluminescence (RL) measurement of Cs10Tb2Cl17(H2O)14(H3O) in powder form shows that the RL emission integrated in the range of 300-750 nm was ∼16% of BGO powder.

Lost horses on the frontier: K2BiCl5 and K3Bi2Br9

Two missing members, K3Bi2Cl9 and K3Bi2Br9, within the series of Bi-containing defect perovskite halides A3Bi2X9 were sought. K3Bi2Cl9 could not be obtained, but the previously identified but uncharacterized compound K2BiCl5 was prepared. K3Bi2Br9 was successfully prepared. K2BiCl5 and K3Bi2Br9 were synthesized by reactions of binary halides at 450–500 ​°C and their structures were determined by single-crystal X-ray diffraction methods. K2BiCl5 adopts the K2PrCl5-type structure in orthorhombic space group Pnma with Z ​= ​4 and cell parameters of a ​= ​12.5461(7) Å, b ​= ​8.7630(5) Å, and c ​= ​7.9865(5) Å. This structure features one-dimensional columns of edge-sharing BiCl7 capped octahedra. K3Bi2Br9 adopts the Tl3Bi2Br9-type structure in monoclinic space group P21/c with Z ​= ​4 and cell parameters of a ​= ​18.718(3) Å, b ​= ​8.1148(13) Å, c ​= ​13.154(2) Å, and β ​= ​91.329(2)°. In this defect perovskite variant, Bi atoms occupy two-thirds of the octahedral sites formed by close-packed arrays of the K and Br atoms, and the BiBr6 octahedra are connected by corner-sharing within slabs. Among defect perovskite halides A3Bi2X9 containing corner-sharing octahedra, K3Bi2Br9 exhibits the greatest degree of distortion from the ideal cubic perovskite structure observed so far. The band gaps, as measured from optical diffuse reflectance spectra, are 2.8 ​eV for K2BiCl5 and 2.2 ​eV for K3Bi2Br9. Electronic structure calculations indicate an indirect gap for K2BiCl5 and a direct gap with rather flat bands for K3Bi2Br9.

Synthesis, characterization, and computational survey of a novel material template o-xylylenediamine

A new salt Bis(o-xylylenediammonium) tetrachloride monohydrate, denoted by OXDACl, produces a novel organic–inorganic compound with centrosymmetric property, prepared by slow evaporation technique in an aqueous solution. This one has been assumed a pattern in the orthorhombic Pnma space group, and the following crystallographic parameters obtained are a = 9.0677(9) Å, b = 24.282 (2) Å, c = 9.4726 (8) Å, V = 2085.7 (3)Å3 and Z = 4, at 150 K. It is investigated by X-ray diffraction, fluorescence, infrared, and UV–visible spectroscopy. The crystal wrap is endorsed by the O–H···Cl, N–H···Cl hydrogen bond interactions among the organic network and the inorganic one, which stabilize the crystal packing. Besides to get a perception into the attitude of these interconnections, Hirshfeld surfaces analysis have been scrutinized. Computational calculations were performed, employing density functional theory (DFT), and were made by comparison with the experimentally determined structure to examine the molecular structure with geometrical optimization, vibrational, and topological parameters of OXDACl by B3LYP/6–311 + + G(d,p) basis.

Thermally Induced Reversible Metal-to-Metal Charge Transfer in Mixed-Valence {Fe III 4 Fe II 4 } Cubes

Thermally Induced Reversible Metal-to-Metal Charge Transfer in Mixed-Valence {Fe ^III ₄ Fe ^II ₄ } Cubes

Heterovalent BiIII/PbII Ionic Substitution in One-Dimensional Trimethylsulfoxonium Halide Pseudo-Perovskites (X = I, Br)

We report on the synthesis and characterization of novel lead and bismuth hybrid (organic–inorganic) iodide and bromide pseudo-perovskites (ABX3) containing the trimethylsulfoxonium cation (CH3)3SO+ (TMSO) in the A site, Pb/Bi in the B site, and Br or I as X anions. All of these compounds are isomorphic and crystallize in the orthorhombic Pnma space group. Lead-based pseudo-perovskites consist of one-dimensional (1D) chains of face-sharing [PbX6] octahedra, while in the bismuth-based ones, the chains of [BiX6] are interrupted, with one vacancy every third site, leading to a zero-dimensional (0D) local structure based on separated [Bi2I9]3– dimers. Five solid solutions for the iodide with different Pb2+/Bi3+ ratios between (TMSO)PbI3 and (TMSO)3Bi2I9, and two for the bromide counterparts, were synthetized. Due to the charge compensation mechanism, these systems are best described by the (TMSO)3Pb3xBi2(1–x)I9 (x = 0.98, 0.92, 0.89, 0.56, and 0.33) and (TMSO)3Pb3xBi2(1–x)Br9 (x = 0.83 and 0.37) formulae. X-ray powder diffraction (XRPD) measurements were employed to determine the crystal structure of all studied species and further used to test the metal cation miscibility within monophasic samples not showing cation segregation. These systems can be described through an ionic defectivity on the pseudo-perovskite B site, where the Pb2+/Bi3+ replacement is compensated by one Pb2+ vacancy for every Bi3+ pair. This leads to a wide range of possible different (numerical and geometrical) chain configurations, leading to the unique features observed in XRPD patterns. The optical band gap of the iodide samples falls in the 2.11–2.74 eV range and decreases upon increasing the Bi3+ content. Interestingly, even a very low loading of Bi3+ (1%) is sufficient to reduce the band gap substantially from 2.74 to 2.25 eV. Periodic density functional theory (DFT) calculations were used to simulate the atomic and electronic structures of our samples, with predicted band gap trends in good agreement with the experimental ones. This work highlights the structural flexibility of such systems and accurately interprets the ionic defectivity of the different pseudo-perovskite structures.

Flux crystal growth of cesium bismuth silicates Cs3BiSi8O19 and Cs4Bi2Si8O21: Structure modification via Eu doping to yield Cs4Bi1.72Eu0.28Si8O21 and alkali metal ion exchange to yield Cs0.79K2.21BiSi8O19

Two new alkali bismuth silicates were prepared via high temperature flux crystal growth and their structures characterized by single crystal X-ray diffraction (SXRD). Cs3BiSi8O19 and Cs4Bi2Si8O21, crystallize in the orthorhombic space groups Pnma (a = 11.5903, b = 7.0346, c = 26.7393) and Pnn2 (a = 14.2674, b = 33.8270, c = 7.24260) respectively. Cs3BiSi8O19 was modified via ion exchange (K for Cs) and Cs4Bi2Si8O21 via Eu doping in a flux environment yielding Cs0.79K2.21BiSi8O19 and Cs4Bi1.72Eu0.28Si8O21, respectively. The two phases crystallize in the orthorhombic space group Cmcm and the monoclinic space group P21/n, respectively. Photoluminescence measurements demonstrated that the europium doped Cs4Bi1.72Eu0.28Si8O21 exhibited emission corresponding to the 5D0 → 7F2 (613 nm) red emission and 5D0 → 7F1 (590 nm) orange emission, characteristic of Eu3+ f-f transitions.

Nitrosonium and Nitronium Salts of New Mixed‐Cation Hexafluoridoantimonates(V)

AbstractReaction between NOSbF6 and Cu(SbF6)2 in aHF yielded NOCu(SbF6)3. In the presence of H3OSbF6, single crystals of (H3O)0.2(NO)0.8Cu(SbF6)3 were grown from a saturated aHF solution. Both salts are isotypic and crystallize in the orthorhombic space group Pnma (No. 62) at 200 K. The main feature of their crystal structures are rings of CuF6 octahedra sharing apexes with SbF6 octahedra connected into 3‐D network. Single charged cations are located inside the cavities. Reaction between 0.25NOSbF6, 0.75NO2SbF6 and Cu(SbF6)2 in aHF yielded (NO)0.25(NO2)0.75Cu(SbF6)3 upon the crystallization. It crystallizes in the cubic space group Im (No. 204) at 200 K. Subsequent experiments with M(SbF6)2 (M=Cu, Zn) showed that, when the NO+ cations are partially or completely replaced by H3O+, the grown crystals of (H3O)0.125(NO)0.125(NO2)0.75Zn(SbF6)3 and (H3O)0.25(NO2)0.75M(SbF6)3 (M=Cu, Zn) are isotypic to (NO)0.25(NO2)0.75Cu(SbF6)3. Crystal structure of the latter demonstrates similar 3‐D structural motif as observed for the NOCu(SbF6)3 salt. The crystal structures of (H3O)0.64(NO2)0.36CuF(SbF6)2 and [Cu(H2O)6](SbF6)2 were also determined. Crystallizations of NOSbF6/O2SbF6 were carried out in aHF in different molar ratios. The crystal structure determinations of grown single crystals showed that they have the composition (NO)x(O2)1‐xSbF6 (x=0.17, 0.55 0.75) indicating that most likely all phases with x=0–1 exist. They are isotypic to NOSbF6.

Synthesis and Characterization of LiFe&lt;sub&gt;1-x&lt;/sub&gt;Gd&lt;sub&gt;x&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;/C (x = 0.01; 0.05; 0.07) for a Lithium Battery Cathode

Synthesis of LiFe1-xGdxPO4/C with (x = 0.01; 0.05; 0.07) have been carried out using a solid-state method from LiH2PO4, Fe2O3, Gd2O3, and Carbon. Al reactant are mixed and mashed with a ball milling for 8 hours, then heated at 80°C for 2 hours to evaporate free water. To complete the reaction, the sample then was sintered at two different temperature; first at 350°C for 6 hours and continue at 830°C for 10 hours under Argon gas (Ar) atmosphere. The sintered powder was characterized by XRD to determine the structure and phase purity. Sample LiFe1-xGdxPO4/C (x = 0.01; 0.05; 0.07) was adopted orthorhombic crystal structure and pnma space group, and no impurities detected. In general, the lattice parameter decreases with increasing Fe concentration, because of the size of the Fe3+ ion is smaller than that Gd3+ ion. Conductivities of LiFe0.93xGd0.07PO4/C, LiFe0.95Gd0.05PO4/C and LiFe0.99Gd0.01PO4/C are 2.17 x 10-4 S/cm, 1.54 x 10-4 S/cm, and 2.02 x 10-4 S/cm, respectively.

Temperature evolution of 3d- and 4f-electron magnetic ordering in the ferrimagnetic Mn self-doped perovskite (Yb0.667Mn0.333)MnO3

A high-pressure synthesis method was employed to prepare Mn-self-doped perovskites (R 0.667Mn0.333)MnO3 (R = Yb, Lu) at about 6 GPa and 1670 K. Crystal and magnetic structures of (Yb0.667Mn0.333)MnO3 have been studied by combining neutron powder diffraction, magnetic susceptibility and specific heat measurements. Within the orthorhombic space group Pnma, magnetic cations are located on site 4c (A site, occupied by two thirds of Yb3+ and one third of Mn2+) and on site 4b (B site, occupied by two thirds of Mn3+ and one third of Mn4+). The degree of structural distortion of the MnO6 octahedra follows the general trend of (R1−x Mn x )MnO3 compounds which shows a decrease with increasing amount of Jahn–Teller inactive Mn4+ cations. Mn–Mn interactions produce a collinear ferrimagnetic structure (T C,Mn = 106 K) with ferromagnetically ordered Mn moments at the B site being coupled antiferromagnetically with ordered Mn moments at the A site. Mn–Yb interactions induce a small but non-zero ferromagnetic Yb3+ moment which can explain a small decrease of the magnetic susceptibility at low temperature. Yb–Yb interactions create an antiferromagnetic structure at T N,Yb ≈ 40 K. Ordered moments of the ferrimagnetic and antiferromagnetic structures are oriented perpendicular to each other within the ac-plane and Yb3+ moments contribute to both structures. The appearance of ordered Yb3+ moments induced by Mn–Yb interactions in perovskite (Yb0.667Mn0.333)MnO3 is a result of the Mn self-doping on the A site and has not been observed in the orthorhombic perovskite modification (space group Pnma) of the undoped parent compound YbMnO3, but interestingly, it also appears in the hexagonal non-perovskite modification (space group P63 cm) of YbMnO3.

Investigation on structure and stability of cerium doped (Ba0.5Sr0.5)(Fe1-xCex)O3-δ (x = 0–1.0) oxides by Rietveld refinement

Perovskite-type materials have been attracted due to their relevant applications in memory devices, tunable microwave displays, oxygen-permeable membranes, sensors, and capacitors. An attempt has been made here to analyze the structure of (Ba0.5Sr0.5)(Fe1-xCex)O3-ẟ (x = 0–1.0) oxides by Rietveld refinement under different space groups. It possesses cubic (space group Pm3m, Z = 1), cubic with orthorhombic, and orthorhombic (space group Pnma, Z = 4) structures for the composition x = 0, 0.10–0.60, and 0.80–1.0, respectively. The amount of cubic phase decreases from 100% to 24% with cerium content (x) = 0–0.60 and complete transformation to the orthorhombic phase occurred at x = 0.80. Moreover, single – dual - single structural phase transitions have been observed. The average bond length decreases with cerium content. The bond angles along O–B–O and B–O–B are deviated significantly due to the tilting and rotation of (Ce,Fe)O6 octahedra. The presence of distortion/oxygen vacancies makes the compound useful in industrial applications.

Sr9Mg4.45(1)Bi9 and Sr9Mg4.42(1)Sb9: Mg-Containing Zintl Phases with Low Thermal Conductivity.

Zintl phases with nominal 9-4-9 formulas are very interesting for their potential applications as thermoelectric materials. However, the formation of such phases usually requires divalent transition metals, for example, Zn, Mn, and Cd, which are covalently bonded to the pnictogen atoms. In this report, for the first time, two Mg-containing compounds with such structures as Sr9Mg4.45(1)Bi9 and Sr9Mg4.42(1)Sb9 were synthesized and their structures were determined by the single-crystal X-ray diffraction method. Both title compounds crystallize in the orthorhombic space group Pnma and are isostructural with Ca9Mn4.41(1)Sb9, which features complex polyanion structures compared to the classical 9-4-9 phases. For Sr9Mg4.45(1)Bi9, its low thermal conductivity, combined with its high electrical conductivity and moderate Seebeck coefficient, leads to a decent figure of merit of 0.57 at 773 K, which obviously prevails in the unoptimized 9-4-9 phases. The discovery of such Mg-containing 9-4-9 phases is very significant, as the discovery not only enriches the structure map of the well-known 9-4-9 family but also provides very valuable thermoelectric candidates surely deserving of more in-depth investigation.