A new gallium-rich intermetallic Ti2-xNi3Ga9 was synthesized by high-temperature techniques as bulk samples and single crystals. The composition and structure of the compound were established by a combination of singlecrystal and powder X-ray analysis and energy-dispersive X-ray spectroscopy. The obtained intermetallic compound crystallizes in its own structure type and has a narrow homogeneous region of x similar to 0.3-0. The topological relationship between Ti2-xNi3Ga9 and HoCoGa5-type structure was established. DFT calculations on the electronic structure of Ti2-xNi3Ga9 confirm metallic nature of the compound, while bonding analysis results favor the bonding scheme in Ti2-xNi3Ga9 as compared to its HoCoGa5-type hypothetical analogue.

Two platinide plumbides, Eu2Pt3Pb5 and SrPt2Pb4, were discovered using high-temperature exploratory synthesis and flux-assisted crystal growth. Their crystal structures were determined from single-crystal X-ray diffraction. Both compounds crystallize in the orthorhombic system; Eu2Pt3Pb5 belongs to the Y2Rh3Sn5 structure type (Cmc21, a = 4.6146(2) Å, b = 27.3082(12) Å, c = 7.5147(3) Å, Z = 4, R1 = 0.0310, and wR2 = 0.0736) and SrPt2Pb4 to the NdRh2Sn4 type (Pnma, a = 19.411(5) Å, b = 4.5834(13) Å, c = 7.6548(19) Å, Z = 4, R1 = 0.0399, and wR2 = 0.0906). Both compounds feature complex frameworks of Pt-Pb and Pb-Pb bonds with very similar motifs, with Eu or Sr cations filling the cavities, which differ by the presence of the TiNiSi-type EuPtPb layer in Eu2Pt3Pb5. According to the DFT calculations, both compounds are metallic and feature Sr and Eu divalent cations along with a negatively charged mostly covalent framework of Pt and Pb atoms. Magnetic measurements show that the SrPt2Pb4 compound is non-magnetic, while Eu2Pt3Pb5 is a paramagnet above ca. 85 K and below that temperature transitions to the ferromagnetically ordered state with very low coercivity.

Two quaternary phosphide platinides, Eu2Pt7MnP2.96 (I4/mmm, a = 4.0453(7) A, c = 26.745(4) A, V = 437.67 (17) A3, Z = 2, R1 = 0.0262, wR2 = 0.0527) and Ca2Pt7MnP3.02 (I4/mmm, a = 4.0027(5) A, c = 26.735(5) A, V = 428.34(14) A3, Z = 2, R1 = 0.0280, wR2 = 0.0673) were synthesized as single crystals and bulk samples, their crystal structures were established from single-crystal X-ray diffraction data and confirmed by powder diffraction and elemental analysis. The compounds crystallize in the tetragonal system, and represent heterostructures built from the alternating layers of AuCu3- and CaBe2Ge2-type fragments. Both compounds are metallic based on the DFT calculations. Chemical bonding analysis reveals a pattern of covalent and ionic interactions within each compound. Magnetic measurements show both compounds to be ferromagnetic, and reveal an interplay between europium and manganese magnetic lattices, indicative of an exchange bias effect.

New platinum-based intermetallic Pt5Mn2Ge was obtained as a bulk sample using arc-melting of the elements with subsequent high-temperature annealing. The structure of the compound was refined using full-profile Rietveld method. Pt5Mn2Ge is isotypic to recently discovered Pt5Mn2Si and crystallizes in the Rh5Ga2As structure type, space group Pbam, a = 5.3791(5) angstrom, b = 10.982(1) angstrom, c = 4.0201(3) angstrom, Z = 2, an ordered variation of the Rh5Ge3 structure type. DFT calculations predict Pt5Mn2Ge to be a metallic conductor. Magnetic measurements show that the compound has a magnetic transition below ca. 100 K, most likely attributed to ferrimagnetic ordering. This compound is only the second one reported in the Pt-Mn-Ge system.

The synthesis of a cubic langbeinite NaZr 2 (PO 4 ) 3 via an ion exchange reaction supported by mechanochemical activation is described. The crystal structure and Na transport properties are studied. HT XRD reveals negative thermal expansion.

New platinum-based intermetallic Pt5Mn2Ge was obtained as a bulk sample using arc-melting of the elements with subsequent high-temperature annealing. The structure of the compound was refined using full-profile Rietveld method. Pt5Mn2Ge is isotypic to recently discovered Pt5Mn2Si and crystallizes in the Rh5Ga2As structure type, space group Pbam, a = 5.3791(5) Å, b = 10.982(1) Å, c = 4.0201(3) Å, Z = 2, an ordered variation of the Rh5Ge3 structure type. DFT calculations predict Pt5Mn2Ge to be a metallic conductor. Magnetic measurements show that the compound has a magnetic transition below ca. 100 K, most likely attributed to ferrimagnetic ordering. This compound is only the second one reported in the Pt–Mn–Ge system.

Series of compounds Ni3 – xMTe2 (M = Sb, Sn; x = 0–1) were obtained by high-temperature sealed-tube synthesis and characterized by X-ray powder diffraction and 121Sb and 119Sn Mössbauer spectroscopy. For Ni3–xSnTe2, it was shown that, as х varies from 1 to 0, nickel is distributed over three possible sites, two of which give a total occupancy of 1 and have ordered vacancies. Meanwhile, for Ni3–xSbTe2 and х other than 0.9–1.0, the vacancy ordering disappears. The temperature dependence of the presence or absence of vacancy ordering was established for Ni2SbTe2; the ordering disappears on heating above 600°C and appears again on cooling.

Series of compounds Ni3 – xMTe2 (M = Sb, Sn; x = 0–1) were obtained by high-temperature sealed-tube synthesis and characterized by X-ray powder diffraction and 121Sb and 119Sn Mössbauer spectroscopy. For Ni3–xSnTe2, it was shown that, as х varies from 1 to 0, nickel is distributed over three possible sites, two of which give a total occupancy of 1 and have ordered vacancies. Meanwhile, for Ni3–xSbTe2 and х other than ~0.9–1.0, the vacancy ordering disappears. The temperature dependence of the presence or absence of vacancy ordering was established for Ni2SbTe2; the ordering disappears on heating above 600°C and appears again on cooling.

Three new mixed nickel-aluminum chalcogenides, Ni6.07AlS2, Ni5.61AlSe2, and Ni5.70AlTe2, have been synthesized by a high-temperature ampoule route using the addition LiCl and KCl. The former compound was characterized from single-crystal synchrotron and powder diffraction data, and the latter two by powder diffraction data. All compounds crystallize in the tetragonal system with I4/mmm space group and belong to the relatively uncommon Ni7-xMQ2 structure type (M - main-group metal). The compounds Ni5.61AlSe2 and Ni5.70AlTe2 represent first ternaries discovered in the respective systems. The main heterometallic structural units of all three compounds are aluminum-centered [Ni12Al] cuboctahedra of the AuCu3-type, single-stacked along the c axis, alternating with [Ni4-xQ2] (Q = S, Se, Te) along the c axis with either nickel-sulfur fragments of the Li2O and defective Cu2Sb/NaCl type, or with nickel-selenium/nickel-tellurium fragments of the defective Cu2Sb/NaCl type respectively. According to the DFT calculations, electronic structures of these ternary compounds are directly related to their parent intermetallic Ni3Al. Non-zero density of states (DOS) at the Fermi level for all compounds indicates metallic conductivity. The ELF topological analysis has shown four-center 3Ni thorn Al bonds both in Ni3Al and ternary nickel-aluminum chalcogenides, with additional pairwise nickel-chalcogen interactions in the latter. Magnetic measurements on Ni6.07AlS2 show the temperature-independent Pauli-like paramagnetism, predicted by DFT calculations for all three chalcogenides, which is in contrast with ferromagnetic behavior of its parent intermetallic.

−The high-temperature thermal expansion and electrical conductivity of the T*-phase cuprates La1.2 – xSrxTb0.8CuO4 ± δ (x = 0, 0.05) were studied for the first time with the goal to evaluate their applicability as cathode materials for solid-oxide fuel cells. According to dilatometry data, the thermal expansion coefficients (TECs) of the oxides in air in the temperature range of 303–1123 K were 12.2 (x = 0) and 12.7 ppm K–1 (x = 0.05). A study of high-temperature crystal structure of La1.2Tb0.8CuO4 ± δ revealed anisotropy of TEC along crystallographic axes (TEC(c)/TEC(a) = 1.35). Analysis of high-temperature electrical conductivity of the cuprates at various oxygen partial pressures showed that holes are the main charge carriers. The conductivity at 973 K in air was 0.3–0.6 S/cm. A possible reason for relatively low conductivity is the formation of Tb4+ cations at high temperature, which act as traps for main charge carriers. The results of this study indicate that La1.2 – xSrxTb0.8CuO4 ± δ may have only limited applicability as the cathode material in SOFC, for example, as thin film functional coatings.

Two new mixed nickel-gallium chalcogenides, Ni9.39Ga2S2 and Ni5.80GaTe2, and a new mixed nickel-indium telluride, Ni5.78InTe2, have been synthesized by a high-temperature ampoule route with the addition of iodine, and characterized from single-crystal or powder diffraction data. They belong to the relatively uncommon Ni7-xMQ2/Ni10-xM2Q2 type of structures (M = Ge, Sn, Sb, In), and are built from p-block metal-centered nickel cuboctahedra, alternating along the c axis with defective Cu2Sb-type nickel-chalcogen ones. Both tellurium-containing compounds show a small degree of orthorhombic distortion with respect to the idealized tetragonal structure, only detectable in the powder diffraction data. No phase transition to the tetragonal structure was detected for Ni5.80GaTe2 by the in situ powder diffraction measurements from room temperature to 550 °C. DFT calculations show close relationships of electronic structures of these ternary compounds to their parent intermetallics, Ni3M (M = Ga, In). Metallic conductivity and paramagnetic properties are predicted for all three with the latter confirmed by magnetic measurements. The bonding patterns, investigated via the ELF topological analysis, show multi-centered nickel - p-block metal bonds in the AuCu3-type fragments and pairwise covalent interactions in the nickel-chalcogen fragments. Both Ni7-xMTe2 compounds showed no structural or compositional changes upon high-temperature mid-pressure hydrogenation.

Three rare-earth oxide selenates Ln(2)O(2)SeO(4) (Ln = La, Pr, Nd) have been prepared via double-exchange solid-state reactions between respective LnOCl oxyhalides and potassium selenate. This approach succeeded to obtain singlephase specimens of La2O2SeO4 and Nd2O2SeO4, previously known as transients upon thermal decomposition of the corresponding selenates, as well as a new compound Pr2O2SeO4. Refinement of their crystal structures from powder X-ray diffraction data confirmed previous attributions to the grandreefite (Pb2F2SO4) structure type observed also for the Ln(2)O(2)SO(4) oxide sulfates. According to polythermic X-ray studies, La2O2SeO4 is stable until at least 700 degrees C. All compounds were characterized by infrared and X-ray photoelectron spectroscopy.

Directional point-contact spectroscopy measurements were performed for the first time in state-of-the-art MgB2 single crystals. The selective suppression of the superconductivity in the π band by means of a suitable magnetic field allowed separating the partial contribution of each band to the total point-contact conductance. By fitting the partial conductance curves σσ(V ) and σπ(V ), we got an independent determination of the two gaps, ∆σ and ∆π, with a strong reduction of the experimental uncertainty. Their temperature dependence was found to agree well with the predictions of the two-band models for MgB2.

Three metal-rich palladium-zinc and platinum-zinc selenium- and phosphorus-containing compounds, Pd5ZnSe, Pd5ZnP, and Pt5ZnP, were synthesized using a high-temperature ampoule technique. Their crystal structures were determined from single-crystal synchrotron data (Pd5ZnSe) or Rietveld analysis of powder diffraction data (Pd5ZnSe, Pd5ZnP, and Pt5ZnP). All the compounds crystallize in tetragonal system with P4/mmm space group and belong to the Pd5TlAs structure type, with their main structural units being zinc-centered [TM12Zn] cuboctahedra (TM = Pd, Pt) of the AuCu3-type, single-stacked along the c axis, alternating with [TM8P] rectangular prisms of the PtHg2 type. DFT electronic structure calculations predict all compounds to be 3D metallic conductors and to show diamagnetic behavior. Charge density analysis shows that all compounds are intermetallic in nature. According to the bonding analysis based on the electron localizability indicator topology, all compounds in the TM(5)MQ series (TM = Pd, Pt; M = Zn, Cd, Hg; Q = Se, P) feature four-centered interactions of the 3TM + M type between the transition metal and group 12 atoms in their heterometallic fragments. Additionally, essentially pairwise interactions between platinum atoms are also observed, indicating a somewhat more localized bonding in the case of platinum-based compounds. The use of iodine-assisted synthesis in the Pd Zn Se system reveals a new compound, Pd8Zn2Se, that exists as an admixture to Pd5ZnSe and, according to the Rietveld refinement data, can be regarded a second homologue to Pd5ZnSe.

Three solid solutions in the Pd–Bi–Te system were obtained by high-temperature ampoule synthesis from the elements at 700°C. The crystal structures of the solid solutions were determined using powder diffraction data by the full-profile Rietveld method. The solid solutions PdTe0.33Bi0.67 (a = 4.19816(8) Å, c = 5.6861(1) Å), PdTe0.5Bi0.5 (a = 4.18888(9) Å, c = 5.6778(1) Å), and PdTe0.67Bi0.33 (a = 4.17796(8) Å, c = 5.6733(1) Å) belong to the PdTe1 – xBix series: the structures of compounds are based on the statistical substitution of Bi atoms for Te atoms in the PdTe structure (NiAs type, hexagonal system, space group P63/mmc). The concentration limit for substitution in the PdTe1 – xBix series of solid solutions is in the 0.67 < x < 0.8 range. Band structure calculations demonstrate the metallic nature for all compounds and similar electronic structures for PdTe, PdTe1– xBix, and PdBi.

A new Sillen - Aurivillius family of layered bismuth oxyhalides has been designed and successfully constructed on the basis of PbBiO2X (X = halogen) synthetic perites and gamma-form of Bi2VO5.5 solid electrolyte. This demonstrates, for the first time, the ability of the latter to serve as a building block in construction of mixed-layer structures. The parent compound PbBi3VO7.5-delta Cl (delta <= 0.05) has been investigated by powder XRD, TEM, XPS methods and magnetic susceptibility measurements. An unexpected but important condition for the formation of the mixed-layer structure is partial (ca. 5%) reduction of V-V into V-IV which probably suppresses competitive formation of apatite-like Pb - Bi vanadates. This reduction also stabilizes the gamma polymorphic form of Bi2VO5.5 not only in the intergrowth structure, but in Bi2V1- xMxO5.5-y (M = Nb, Sb) solid solutions. (C) 2017 Elsevier Masson SAS. All rights reserved.

Co-precipitation of PbF2 and PbSeO4 in weakly acidic media results in the formation of [Pb2F2](SeO4), the selenate analogue of the naturally occurring mineral grandreefite, [Pb2F2](SO4). The new compound is monoclinic, C2/c, a = 14.0784(2) Å, b = 4.6267(1) Å, c = 8.8628(1) Å, β = 108.98(1)°, V = 545.93(1) Å3. Its structure has been refined from powder data to R B = 1.55%. From thermal studies, it is established that the compound is stable in air up to about 300 °C, after which it gradually converts into a single phase with composition [Pb2O](SeO4), space group C2/m, and lattice parameters a = 14.0332(1) Å, b = 5.7532(1) Å, c = 7.2113(1) Å, β = 115.07(1)°, V = 527.37(1) Å3. It is the selenate analogue of lanarkite, [Pb2O](SO4), and phoenicochroite, [Pb2O](CrO4), and its crystal structure was refined to R B = 1.21%. The formation of a single decomposition product upon heating in air suggests that this happens by a thermal hydrolysis mechanism, i.e., Pb2F2SeO4 + H2O (vapor) → Pb2OSeO4 + 2HF↑. This relatively low-temperature process involves complete rearrangement of the crystal structure—from a 2D architecture featuring slabs [Pb2F2]2+ formed by fluorine-centered tetrahedra into a structure characterized by 1D motifs based on [OPb2]2+ chains of oxocentered tetrahedra. The comparative crystal chemistry of the obtained anion-centered structural architectures is discussed.

The quaternary compounds EuMnPnF (Pn = P, As, Sb) have been prepared via solid state route at 1173K, and their crystal and electronic structures as well as magnetic and transport properties have been elucidated. These compounds belong to the widespread LaAgSO structure type and crystallize in tetragonal (P4/nmm) unit cells with a = 4.0292(1) Å, c = 8.9505(2) Å for EuMnPF, a = 4.1227(1) Å, c = 9.0846(2) Å for EuMnAsF, and a = 4.3120(1) Å, c = 9.4356(2) Å for EuMnSbF. At low temperatures, the magnetic response is dominated by Eu2+. Contrary to previous reports, we do not observe any magnetic transitions in EuMnPF down to 2K, whereas its arsenide and antimonide analogs exhibit Eu2+ ordering around 3K. According to the electrical resistivity measurements and density-functional calculations, all three compounds are narrow-gap semiconductors.

A new intermetallic compound, ternary antimonide Eu7Cu44Sb23-delta [Fm-3m, a = 17.4346(1)angstrom, delta = 0.5(1)] is reported. The compound forms a continuous substitutional solid solution with its Eu7Cu44As23 archetype. The gradual substitution of Sb for As evokes partial disorder in the copper-pnictogen framework that becomes more pronounced with an increase of the Sb content and changes magnetic properties. Whereas Eu7Cu44As23 is metallic ferromagnet below 17 K, Eu7Cu44Sb23-delta shows paramagnetic behavior down to 1.8 K according to the magnetic measurements, while retaining metallic properties according to the DFT calculations. The origin of the disorder, the structure-property relationships, as well as prospects of further substitution in the anionic sub lattice are discussed.

Step-wise reaction of CdO, Bi2O3, and Cd(NO3)(2)center dot 4H(2)O leads to formation of a novel bismuth oxide nitrate, CdBiO2NO3, which completes the family of bis-muthite-like (MBiO2NO3)-Bi-II oxide nitrates. The new compound is tetragonal, I4/mmm, a = 3.9486(1)angstrom, c = 14.2235(2)angstrom; its crystal structure resembles those of PbBiO2NO3 and CdBiO2NO3, except for, probably, different positioning of the nitrate group. The compound is stable until similar to 425 degrees C when it decomposes, in one step, into CdO and a mixture of Bi-Cd oxides. Cd-based analogs of isostructural PbLnO(2)NO(3 )(Ln - lanthanides) oxide nitrates are unlikely to exist. We discuss the similarities and differences in the structures of layered oxyhalides and oxynitrates of bismuth and rare-earths.