18810-58-7Relevant academic research and scientific papers
Electronic and ionic conductivity in alkaline earth diazenides M AEN2 (MAE = Ca, Sr, Ba) and in Li 2N2
Schneider, Sebastian B.,Mangstl, Martin,Friederichs, Gina M.,Frankovsky, Rainer,Schmedt Auf Der Guenne, Joern,Schnick, Wolfgang
, p. 4149 - 4155 (2013)
Electrical conductivity measurements of alkaline earth diazenides SrN 2 and BaN2 revealed temperature-dependent metal-like behavior. As CaN2 is isotypic with SrN2 its electronic properties are supposed to show similar characteristics. For the alkali diazenide Li2N2, the corresponding measurement shows not only the typical characteristics of metallic materials but also an unexpected rise in electrical conductivity above 250 K, which is consistent with an ionic contribution. This interpretation is further corroborated by static 6Li and 7Li nuclear magnetic resonance measurements (NMR) of the spin-lattice relaxation time (T1) over an extended temperature range from 50 to 425 K. We observe a constant Heitler-Teller product (T 1T) as expected for metals at low temperatures and a maximum in the temperature-dependent relaxation rates, which reflects the suggested ionic conductivity. A topological structural analysis indicates possible 3D ion migration pathways between two of the three crystallographic independent Li positions. A crude estimate of temperature-dependent self-diffusion coefficients D(T) of the lithium motion classifies Li2N2 as a mixed electronic/ionic conductor.
High-Pressure synthesis of BaSr2P6N12 and BaCa2P6N12 and comparison of the structures of BaP2N4, BaCa2P6N12, and BaSr2P6N12
Karau, Friedrich,Schnick, Wolfgang
, p. 231 - 237 (2006)
The novel nitridophosphates BaCa2P6N12 and BaSr2P6 N12 were obtained by means of high-pressure high-temperature synthesis utilizing the multianvil technique (1200°C, 5 GPa). The complex anion [PN2-] of the title compound is formally isoelectronic with silica. The crystal structure was solved from powder data and refined by the Rietveld method (BaCa 2P6N12: Pa3, Z = 4, a = 9,9578(2) A; BaSr2P6N12: Pa3, Z = 4, 10,0705(2) A). The crystal structures are derived from that of BaP2N4 which is isotypic with a high pressure phase of CaB2O4 and BaGa2S4. For each compound the 31P solid state NMR spectrum yielded a single resonance (BaCa2P6N 12: 7.4 ppm; BaSr2P6N12:3.9 ppm).
Preparation and crystal structure of Ba2NF
Seibel,Wagner
, p. 2772 - 2776 (2004)
Single crystalline Ba2NF was prepared by heating a mixture of KCuF3 and Ba metal to 900°C under dynamic flow of N2, followed by slow cooling from the melt. Crystals of Ba2NF were dark violet in color and very air sensitive. X-ray diffraction experiments revealed that Ba2NF is isostructural with rocksalt-type BaO, and has space group Fm-3m (No. 225) with cell parameter of a=5.6796(19)A, Z=2. X-ray data was collected on a Bruker SMART APEX 4k CCD Single Crystal Diffractometer at 100K, using Mo(Kα) radiation. Structure refinement was carried out by full-matrix least squares on F2 on all data, to give R1=0.0194 (all data) and wR2=0.0433 for 3 parameters and 23 independent reflections. The final position assignments were analyzed via bond valence sum calculations.
High-pressure synthesis and X-ray powder structure determination of the nitridophosphate BaP2N4
Karau, Friedrich W.,Schnick, Wolfgang
, p. 135 - 141 (2005)
The novel nitridophosphate BaP2N4 was obtained by means of high-pressure high-temperature synthesis utilizing the multianvil technique (8 GPa, 1400°C). The [PN2]- network is isoelectronic with silica. The structure was solved from synchrotron powder data by a combination of direct methods and difference FOURIER synthesis and refined using the RIETVELD method (BaP2N4, Pa3, Z = 12, a = 10.22992(2)A). BaP2N4 is isotypic with BaGa 2S4, BaAl2S4 and the high-pressure phase of CaB2O4. The 31P solid-state NMR yielded a single sharp resonance at 0.4 ppm.
Synthesis of alkaline earth diazenides MAEN2 (M AE = Ca, Sr, Ba)by Controlled Thermal Decomposition of Azides under High Pressure
Schneider, Sebastian B.,Frankovsky, Rainer,Schnick, Wolfgang
, p. 2366 - 2373 (2012)
The alkaline earth diazenides MAEN2 with M AE = Ca, Sr andBa were synthesized by a novel synthetic approach, namely, a controlleddecomposition of the corresponding azides in a multianvil press at highpressure/high-temperature conditions. The crystal structure of hithertounknown calcium diazenide (space group I4/mmm (no. 139), a = 3.5747(6)A, c = 5.9844(9)A, Z = 2, wRp = 0.078)was solved and refined on the basisof powder X-ray diffraction data as well as that of SrN 2 and BaN2.Accordingly, CaN2 is isotypic with SrN2 (space group I4/mmm (no. 139), a =3.8054(2)A, c = 6.8961(4)A, Z = 2, wRp = 0.057)and the correspondingalkaline earth acetylenides (MAEC2)crystallizing in a tetragonally distortedNaCl structure type. In accordance with literature data, BaN2 adopts a moredistorted structure in space group C2/c (no. 15)with a = 7.1608(4)A, b =4.3776(3)A, c = 7.2188(4)A, β = 104.9679(33)°, Z = 4 and wRp = 0.049).The N-N bond lengths of 1.202(4)A in CaN2 (SrN2 1.239(4)A, BaN21.23(2)A)correspond well with a double-bonded dinitrogen unit confirming a diazenide ion [N 2]2-. Temperature-dependent insitu powder X-ray diffractometry of the three alkaline earth diazenides resulted in formation of the corresponding subnitridesMAE2N (MAE = Ca, Sr, Ba)at higher temperatures. FTIR spectroscopy revealed a band at about 1380 cm-1 assigned to the N-Nstretching vibration of the diazenide unit. Electronic structure calculations support the metallic character of alkaline earthdiazenides.
BaP6N10NH:Eu2+ as a Case Study–An Imidonitridophosphate Showing Luminescence
Eisenburger, Lucien,Günther, Daniel,Oeckler, Oliver,Schmidt, Peter J.,Schnick, Wolfgang,Wendl, Sebastian,Wright, Jonathan P.,Zipkat, Mirjam
, (2020)
Barium imidonitridophosphate BaP6N10NH was synthesized at 5 GPa and 1000 °C with a high-pressure high-temperature approach using the multianvil technique. Ba(N3)2, P3N5 and NH4Cl were used as starting materials, applying a combination of azide and mineralizer routes. The structure elucidation of BaP6N10NH (P63, a=7.5633(11), c=8.512(2) ?, Z=2) was performed by a combination of transmission electron microscopy and single-crystal diffraction with microfocused synchrotron radiation. Phase purity was verified by Rietveld refinement. 1H and 31P solid-state NMR and FTIR spectroscopy are consistent with the structure model. The chemical composition was confirmed by energy-dispersive X-ray spectroscopy and CHNS analyses. Eu2+-doped samples of BaP6N10NH show blue emission upon excitation with UV to blue light (λem=460 nm, fwhm=2423 cm?1) representing unprecedented Eu2+-luminescence of an imidonitride.
Nitridophosphate-Based Ultra-Narrow-Band Blue-Emitters: Luminescence Properties of AEP8N14:Eu2+ (AE=Ca, Sr, Ba)
Wendl, Sebastian,Eisenburger, Lucien,Strobel, Philipp,Günther, Daniel,Wright, Jonathan P.,Schmidt, Peter J.,Oeckler, Oliver,Schnick, Wolfgang
, p. 7292 - 7298 (2020)
The nitridophosphates AEP8N14 (AE=Ca, Sr, Ba) were synthesized at 4–5 GPa and 1050–1150 °C applying a 1000 t press with multianvil apparatus, following the azide route. The crystal structures of CaP8N14 and SrP8N14 are isotypic. The space group Cmcm was confirmed by powder X-ray diffraction. The structure of BaP8N14 (space group Amm2) was elucidated by a combination of transmission electron microscopy and diffraction of microfocused synchrotron radiation. Phase purity was confirmed by Rietveld refinement. IR spectra are consistent with the structure models and the chemical compositions were confirmed by X-ray spectroscopy. Luminescence properties of Eu2+-doped samples were investigated upon excitation with UV to blue light. CaP8N14 (λem=470 nm; fwhm=1380 cm?1) and SrP8N14 (λem=440 nm; fwhm=1350 cm?1) can be classified as the first ultra-narrow-band blue-emitting Eu2+-doped nitridophosphates. BaP8N14 shows a notably broader blue emission (λem=417/457 nm; fwhm=2075/3550 cm?1).
Ba3P5N10Br:Eu2+: A natural-white-light single emitter with a zeolite structure type
Marchuk, Alexey,Schnick, Wolfgang
, p. 2383 - 2387 (2015)
Illumination sources based on phosphor-converted light emitting diode (pcLED) technology are nowadays of great relevance. In particular, illumination-grade pcLEDs are attracting increasing attention. Regarding this, the application of a single warm-white-emitting phosphor could be of great advantage. Herein, we report the synthesis of a novel nitrido-phosphate zeolite Ba3P5N10Br:Eu2+. Upon excitation by near-UV light, natural-white-light luminescence was detected. The synthesis of Ba3P5N10Br:Eu2+ was carried out using the multianvil technique. The crystal structure of Ba3P5N10Br:Eu2+ was solved and refined by single-crystal X-ray diffraction analysis and confirmed by Rietveld refinement and FTIR spectroscopy. Furthermore, spectroscopic luminescence measurements were performed. Through the synthesis of Ba3P5N10Br:Eu2+, we have shown the great potential of nitridophosphate zeolites to serve as high-performance luminescence materials.
