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[EN] Ce-N-O system derived from doping of cerium oxide with nitrogen with general formula CeO2-x-yNx, with the same structure as undoped CeO2, and which can have 5 similar uses of great technological and strategic relevance, namely as a solid electrolyte and as a catalyser. The presence of cerium 3+ means that luminescent properties may also be present. This compound is prepared by means of a solid-gas reaction using cerium dioxide and ammonia as starting products. The cerium dioxide is placed in a tubular furnace and heated to temperatures over 10 400 DEG C. and ammonium atmosphere., [ES] El sistema del ce-N-o derivó del doping del óxido de cerio con nitrógeno con la fórmula general CeO2-x-yNx, con la misma estructura que CeO2 undoped, y que el bote tiene 5 usos similares de la grande relevancia tecnológica y estratégica, a saber como electrólito sólido y como catalizador. La presencia de medio del cerio 3+ que las propiedades luminiscentes pueden también estar presentes. Este compuesto se prepara por medio de una reacción del sólido-gas usando el dióxido y el amoníaco del cerio como productos de partida. El dióxido del cerio es colocado en un horno tubular y calentado a las temperaturas sobre 10 400 grados C. y atmósfera del amonio., Consejo Superior de Investigaciones Científicas (España), A1 Solicitud de patente con informe sobre el estado de la técnica

Fecha de solicitud: 27.05.2003.- Titular: Consejo Superior de Investigaciones Científicas (CSIC)., [EN] The invention relates to a novel product containing lithium, oxygen and nitrogen manganese and having formula LiXMnN5-YOY, wherein x is located in the interval 7 to 9 and is greater than 0 and less than or equal to 2. The aforementioned product comprises a disordered anti-fluorite crystalline structure, is obtained by means of a solid state reaction process and has an electrochemical capacity of 360 mAh/g. The invention can be used as a negative electrode material in rechargeable lithium batteries. The main advantage of the invention lies in the fact that the lithium insertion/deinsertion process has greater reversibility than in some products used at present for the same purpose, thereby reducing capacity loss in subsequent charging/discharging cycles. As a result, the rechargeable batteries used perform better and last longer. [ES]La presente invención tiene por objeto un nuevo producto que contiene litio, manganeso nitrógeno y oxígeno y que responde a la fórmula Li

Fecha de solicitud: 03.09.1999.- Titulares: Consejo Superior de Investigaciones Científicas (CISC)., [EN]The production of zirconium and hafnium nitrides and halides comprises synthesis in a closed reactor in a furnace with two heating zones. The synthesis stage is followed by purification in the furnace, and takes place at a uniform temperature in the cold zone. The purification zone operates at a temperature gradient. [ES] Procedimiento de obtención de nitruros-haluros de circonio y hafnio mediante síntesis en reactor cerrado. Procedimiento que se realiza en un reactor estanco en un horno de dos zonas térmicas. El procedimiento consta de dos etapas de síntesis y purificación, que se realizan consecutivamente en el mismo dispositivo experimental. La etapa de síntesis tiene lugar a temperatura uniforme en la zona fría (zona 1) del horno mientras que la etapa de purificación se realiza bajo un gradiente de temperatura (diferencia de temperatura entre las dos zonas del horno).

ChemInform Abstract.

Control of structure and order in oxides is essential for the design of new superconducting cuprates. The intergrowth of perovskite and rock salt layers, as found in bismuth, thallium and, very recently, the record breaking mercury cuprates, is just one way to induce bidimensionality. Defect “all perovskite” oxides, such as Ln2Ba2C2Ti2O11 (Ln = La, Nd, Eu) are discussed as examples of a crystal -chemical approach to the induction of bidimensionality and order in mixed perovskite oxides of copper., This work was supported by the spanish CICYT (MAT90-1020-C02-01) and the MIDAS Program (92–1592). We thank the Departament ďEnsenyament de la Generalitat de Catalunya for a predoctoral fellowship awarded to M. R. P.

Simultaneous electrodeposition of Y, Ba and Cu from solution is achieved in presence of complexing agents, using metal wires as substrates. The resulting wire is superconducting after thermal treatment at 900 °C. The main problem is the presence of excess copper in the deposit that may be easily overcome using cyanide as a complexing agent which inhibits copper deposition in DMSO. On the other hand, deposition of YBa2Cu3O7-δ particles by electrophoresis yields superconducting wires with preferential orientation and high critical currents.

Electrochemical oxidation of La2CuO4 in aqueous OHMIN yield superconducting materials with Tc values that depend on the degree of oxidation and the temperature. The chemical nature of the charge carriers changes with temperature, yielding notable changes in Tc values. For the maximum oxidation of 0.15 holes per copper, an internal redistribution of holes between Cu and O is proposed from RT to 100 °C. Partial derivatives of magnetic susceptibility vs susceptibility show the existence of several coexisting phases with distinct Tc's, possibly within each grain.

We report differential scanning calorimetric analyses of several reactions leading to the formation of the mixed perovskite La2CuTiO6. The synthesis of this oxide was carried out following three different strategies: i) classical ceramic methods, ii) use of a layered oxide precursor (La2CuO4), and iii) sol-gel method. Electron diffraction and neutron diffraction data on the sol-gel product complete the structural characterization of this oxide, which presents an orthorhombically distorted perovskite structure of the GdFeO3 type, with a distortion proportional to the temperature of synthesis. Neutron diffraction shows no long-range order of Cu(II) and Ti(IV) in the structure. Finally, the reduction of this perovskite to yield La2CuTiO5 is reported., We thank the spanish DGICYT (PB93-0122), CICYT (MAT93-0240-C04-01) and the MIDAS Program (92-1592) for financial support, and the Generalitat de Catalunya for a predoctoral fellowship awarded to M.R.P.

Room-temperature electrochemical oxidation of La2CuO4 at the limiting value of 0.15 electrons per formula unit yields bulk superconducting materials with Tc values that depend on the applied potentials and the drying temperature. Superconducting fractions and structural parameters are also strongly dependent on moderate thermal treatments following the synthesis. We propose a reorganization of the charge carriers with temperature, involving charge transfer between Cu and intercalated oxygen atoms, to explain the analytical data obtained for various samples with different thermal treatments. Other cuprates also show the ability to intercalate oxygen. Thus, electrochemical oxidation of La2-xSrxCaCu2O6-δ yields the oxygen stoichiometric phase that, although not superconducting, presents magnetic properties different from its precursor without a notable change in its structure., This work has been supported by the Spanish CICYT (MAT90-1020-C02-01) and the MIDAS Program (92-1592).

Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).-- et al., Measurements of the spin rotation and depolarization of implanted positive muons have revealed that La2SrCu2O6+δ, La2CaCu2O6+δ, and La1.9Y0.1CaCu2O6+δ, members of the double-layer perovskite family La2MCu2O6+δ (M=Ca,Sr), display magnetic ordering similar to that of La2−xSrxCuO4−y and YBa2Cu3Ox Their magnetic order parameters are remarkably close to those of the other layered cuprates. A superconducting minority phase has been detected in La2CaCu2O6+δ (δ≥0.02), with onset at ∼45 K and accompanied by a change in the muon-spin-precession signals from the majority antiferromagnetic phase, phenomena absent in La2SrCu2O6+δ. This behavior was attributed to mobility and local clustering of intercalated oxygen excess in the layer between the CuO2 planes., This work was supported by NSERC (Canada), DOE Grant No. DE-FG05-88ER45353, the CICYT and the MIDAS project (Spain), and the CEE.

The development of new synthetic methodologies of perovskite oxynitrides is challenging but necessary for the search of new compounds and the investigation of new properties. Here, we report a new method of preparation of the perovskite LaTaON2 that has been investigated as a pigment and photocatalyst for water splitting. The synthesis proceeds through the solid-state reactions under N2 at 1500 °C between La2O3, LaN, and Ta3N5 or between LaN and TaON, which are completed after 3 h and lead to sintered, highly crystalline samples with particle sizes up to 1 μm. Nitrogen-deficient samples LaTaO1+xN2-x with x ≤ 0.35 are prepared by changing the N/O ratio in the mixture of reactants. Electron diffraction, synchrotron diffraction, and neutron diffraction studies on stoichiometric and nitrogen-deficient compounds indicate that they crystallize in the monoclinic space group I2/m with lattice parameters for LaTaON2 of a = 5.71458(7), b = 8.05987(10), c = 5.74772(6) Å, and β = 89.982(3)°. The three anion sites of the I2/m structure are partially occupied by oxygen and nitrogen, with a preference of nitride for two positions with occupancies of 77 and 88%. This anion distribution is different from that reported in previous studies of samples prepared by ammonolysis at lower temperature, suggesting that the synthesis conditions affect the anion order of this perovskite. Optical measurements indicate a band gap of about 1.9 eV, which is close to that observed in samples prepared by other methods. The determined dielectric permittivity for LaTaON2 εr ≈ 200, reported for the first time for a highly nitrided pseudocubic perovskite, is similar to that observed in perovskites with one nitrogen per formula., This work was supported by the Ministerio de Ciencia e Innovación, Spain [MAT2017-86616-R, MAT2017-85232-R, PID2019-107727RB-I00, PID2020-113805GB-I00, PID2020-118479RB-I00, and CEX2019-000917-S], from Generalitat de Catalunya (2017SGR1377 and 2017SGR581) and from CSIC through the i-LINK (LINKA20338) program. The authors thank Alba and ILL for beam time provision (experiments 2017092391 and 5-21-1113, respectively), Dr. François Fauth for assistance in data collection at Alba, and Dr. Bernat Bozzo (ICMAB-CSIC) for performing electrical measurements. The project was also supported by a 2020 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. I.F. acknowledges the Ramón y Cajal contract RYC-2017-22531 and JRG acknowledges the AEAT predoctoral fellowship PRE2018-085204., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

A new solvent free protocol is presented to introduce amide and amine functionalities (N-aliphatic groups) onto graphene oxide in an energy efficient manner. Nitrogen contents of 3.6 wt% are obtained in only 5 minutes at room temperature by using ammonia gas as the nitrogen source for the ammonolysis of graphene oxide, We acknowledge financial support through MAT2017-86616-R grant and the “Severo Ochoa” Programme (SEV-2015-0496)., We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).

The topotactic nitridation of cation ordered, tetragonal Sr2FeMoO6 in NH3 at moderate temperatures leads to cubic, Fm[3 with combining macron]m double perovskite oxynitride Sr2FeMoO4.9N1.1 where double-exchange interactions determine ferromagnetic order with TC ≈ 100 K. Substitution of oxide by nitride induces bond asymmetries and local electronically driven structural distortions, which combined with Fermi level lowering restricts charge itinerancy to confined regions and preclude spontaneous long-range magnetic order. Under a magnetic field, ferromagnetic correlations expand, favoring charge delocalization and a negative magnetoresistance is observed., This work was supported by the Spanish Ministerio de Ciencia, Universidades e Investigación, Spain (Projects MAT2017-86616-R, MAT2017-85232-R, MAT2015-71664-R, MAT2015-67593-P and ENE2015-63969) and by Generalitat de Catalunya (2017SGR1377, 2017SGR581). ICMAB acknowledges financial support from MINECO through the Severo Ochoa Program (SEV-2015-0496). We thank the Institut Laue Langevin (ILL) and Alba synchrotron for the provision of beam time., We acknowledge support of the publication fee by the CSIC Open Access Support Initiative through its Unit of Information Resources for Research (URICI)

Magnetic frustration results from competing magnetic interactions and leads to unusual ground states, ranging from non-collinear magnetic orders to spin liquids (SLs), opening the path to new physics and emerging properties. We report the engineered magnetic interaction design and synthesis of the new ternary nitride MnTa2N4 with a normal spinel structure, where the magnetic cations Mn2+ occupy exclusively the tetrahedral sites forming a diamond lattice. Although the magnetic interactions are strongly antiferromagnetic (θCW ≈ -140 K), a long-range magnetic order is not established, but a smooth magnetic anomaly is observed at T∗ ≈ 5.1 K, fingerprinting a large magnetic frustration. A short-range helicoidal magnetic order emerges at low temperatures. The ordered moment is ≈70% of the expected magnetic moment of Mn2+ ions and a large part (≈28%) of the spin entropy remains at 400 mK, signaling the coexistence of a helicoidal order with spin-glass-like or SL textures. First-principles calculations unveil an unexpected large direct Mn-Mn exchange interaction that balances the superexchange and accounts for the magnetic frustration. These findings open new avenues toward the design of quantum materials., This work was supported by the Ministerio de Ciencia e Innovación, Spain (PID2020-113805GB-I00, PID2020-118479RB-I00 (AEI/FEDER, EU), PGC2018-096955-B-C44 ,PGC2018-093863-B-C22, CEX2019-000917-S and MDM-2017-0767) and from Generalitat de Catalunya (2017SGR1377, 2017SGR581, 2017SGR1506, and 2017SGR1289). We thank Alba and ILL for beam time provision (experiments 2019023454 and 5-31-2713, respectively), Dr. François Fauth for assistance in data collection at Alba, and Dr. Bernat Bozzo (ICMAB-CSIC) for performing magnetic measurements. The authors acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

Rare-earth doped oxynitrides have attracted much attention as phosphors for white LEDs. A new family of Ce3+ or Eu2+-doped oxynitride phosphors with the apatite structure has been studied: La8+xSr2-x(Si/Ge)6NyO26+x/2-3/2y. The ammonolysis of an apatite oxide precursor has been used as a general method of synthesis, allowing decreasing the nitriding temperature respective to the classical solid state reaction in N2/H2 atmosphere. The luminescence properties of the obtained phosphors have been studied and relationships with the crystalline structure have been drawn.The apatite structure shows several crystallographic sites available for nitrogen as well as two cationic sites for optically active rare-earth ions. Several structural characterization technique have been used (IR, Raman, NMR, Neutron diffraction) and important information has been obtained concerning the nitrogen distribution in the available positions of the crystal structure. Comparison of the luminescent properties with those of compounds reduced under Ar/H2 allowed attributing emissions to the different crystallographic sites available in the structure.Quantum efficiency measurements have been carried out as well as trials for improving the intensity of the luminescent properties., Les oxynitrures dopés terre rare présentent des propriétés intéressantes pour un usage en tant que luminophore pour LEDs blanches. Une nouvelle famille de luminophores dopés Eu2+ ou Ce3+ avec un réseau hôte oxynitrure de structure apatite a été étudiée : La8+xSr2-x(Si/Ge)6NyO26+x/2-3/2y. L’ammonolyse d’un précurseur oxyde de structure apatite a été utilisée comme technique générale de nitruration. Elle a permis de diminuer substantiellement la température de nitruration en comparaison avec la méthode classique par réaction à l’état solide sous atmosphère mixte N2/H2. Les différentes luminescences des luminophores obtenus ont été étudiées et corrélées à la structure cristalline à l’aide de différentes techniques de caractérisation.La structure apatite présente notamment la particularité de proposer plusieurs sites anioniques pour l’introduction de l’azote ainsi que deux sites cationiques pour les ions terre rare activateurs. L’utilisation de nombreuses techniques de caractérisation (IR, Raman, RMN, diffraction des neutrons) a permis d’obtenir des informations sur la position de l’azote. En parallèle, la comparaison des propriétés optiques avec celles de composés réduits sous Ar/H2 a permis d’attribuer les émissions aux différents sites cristallins disponibles dans la structure. Des mesures de rendement quantique ainsi que des tentatives d’optimisation des propriétés de luminescence ont été effectuées.