1 / 31

Sebastian B. Schneider, Dominik Baumann Ludwig-Maximilians-Universität München, LMU

Sebastian B. Schneider, Dominik Baumann Ludwig-Maximilians-Universität München, LMU Prof. Dr. Wolfgang Schnick. High-Pressure Synthesis of Novel (Oxo-)Nitridosilicates, (Oxo-)Nitridophosphates and Related Binary Nitrides

cade
Download Presentation

Sebastian B. Schneider, Dominik Baumann Ludwig-Maximilians-Universität München, LMU

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Sebastian B. Schneider, Dominik Baumann Ludwig-Maximilians-Universität München, LMU Prof. Dr. Wolfgang Schnick High-Pressure Synthesis of Novel (Oxo-)Nitridosilicates, (Oxo-)Nitridophosphates and Related Binary Nitrides 5th Berichtskolloquium of SPP 1236 (2009-2012) Bad Salzschlirf, Hessen, Germany 25.9. – 28.09.2012

  2. Why N-based research? specificchemicalandphysicalproperties - highercondensationdegree - higher CN ofthe N-basedanionsthroughhighercoherence - morecovalentbondsthroughlowerelectronegativity comparedto O-basedcompounds resulting in manifoldareasofscienceandindustry • hard material (cuttingandgrindingtool) • - meltingcrucible • - engineering material • potential phosphors in LEDs (after doping) • fundamental research

  3. Synthesis – devices Multianvil press DACs pmax≈ 20 GPa Tmax≈ 1600 °C

  4. I. Novel Si-(O-)N and P-(O-)N compounds with extraordinary properties Highlights in Nitridosilicate and Nitridophosphate chemistry

  5. Novel (Oxo-)Nitridosilicates – an Overview HP-Ca2Si5N8- A New High-Pressure Nitridosilicate: Synthesis, Structure, Luminescence, and DFT-Calculations Compression Behaviour of Nitridocarbidosilicates M2[Si4N6C] M = Y, Ho, Er - Studied with X-ray Diffraction and ab-initio Calculations A Density Functional Study of the High-Pressure Chemistry of MSiN2 (M = Be, Mg, Ca): Prediction of High-Pressure Phases and Examination of Pressure-Induced Decomposition High-Pressure Phases and Transitions of the Layered Alkaline Earth Nitridosilicates SrSiN2 and BaSiN2 Material Properties and Structural Characterization of M3Si6O12N2:Eu2+ (M = Ba, Sr) – A Comprehensive Study on a Promising Green Phosphor for pc-LEDs BaSi4O6N2 – A Hexacelsian-Type Layered Oxonitridosilicate

  6. Novel (Oxo-)Nitridosilicates More details in tonightspostersession

  7. Novel (Oxo-)Nitridophosphates – an Overview Sr3P6O6N8 – A Highly Condensed Layered Phosphate Phenakite-Type BeP2N4 – a Possible Precursor for a New Hard Spinel-Type Material. Electronic Structure and Physical Properties of the Spinel-Type Phase of BeP2N4 from All-Electron Density Functional Calculations High-Pressure Synthesis, Crystal Structure and Characterization of Zn2PN3 – A New Catena-polynitridophosphate. High-Pressure Synthesis and Structural Investigation of H3P8O8N9: A New Phosphorus(V) Oxonitride Imide with an Interrupted Framework Structure An Unprecedented AB2 Tetrahedra Network Structure Type in a High-Pressure Phaseof Phosphorus Oxonitride PON Crystal Structure of Barium Oxonitridophosphate, Ba3P6O6N8

  8. Why work on Nitridophosphates? Si/O P/N 4 + 6 = 10 valenceelectrons SiO2 16/3 valenceelectrons/atom Networks based on SiO4-tetrahedra 5 + 5 = 10 valenceelectrons PN2- 16/3 valenceelectrons/atom Networks based on PN4-tetrahedra Isosteric P/N and Si/O networks? enhancedbondingcapabilitiesof P/N leadto additional possiblenetworksandprobablyinterestingmaterialsproperties!

  9. Nitridophosphates – Examples Nitridophosphateswith Silicate AnalogousStructures β-Cristobalite: LiPN2, NaPN2 Megacalsilite (≡ K[AlSiO4]): SrP2N4 9 K. Landskron, S. Schmid, W. Schnick, Z. Anorg. Allg. Chem.2001, 627, 2469. F.W. Karau, L. Seyfarth, O. Oeckler, J. Senker, K. Landskron, W. Schnick, Chem. Eur. J.2007, 13, 6841.

  10. Nitridophosphates – Examples Nitridophosphateswith Silicate AnalogousStructures P4N4(NH)4(NH3) – a NitridicClathrate - Cage builtupof PN4-tetrahedra - Cage contains NH3molecule - NH3releasedattemperatures > 565 °C 10 F. Karau, W. Schnick, Angew. Chem.2006, 118, 4617; Angew. Chem. Int. Ed. 2006, 45, 4505.

  11. Nitridophosphates – BeP2N4 WhataboutNitridophosphateswith CN(P) > 4? (Stishovite-like) CN(Si) = 6 - A possiblecandidate: BeP2N4 - Isostructuralandisovalence-electronic toβ-Si3N4 - Transition fromphenakitetospinelstructure type seemslikely - CN(P) = 4  CN(P) = 6 c-Si3N4 HP/HT CN(Si) = 4 11 F.J. Pucher, S.R. Römer, F.W. Karau, W. Schnick, Chem. Eur. J.2010, 16, 7208; W.Y. Ching, S. Aryal, P. Rulis, W. Schnick, Phys. Rev. B2011, 83, 155109-1.

  12. Nitridophosphates – BeP2N4 Synthesis of BeP2N4 5 GPa/1500°C Be3N2 + 2 P3N5 3 BeP2N4 - Isotypicto Be2SiO4 (phenakite) andβ-Si3N4 - Ionicradiiof Si and P aresimilar - Network builtupof PN4- (blue) and BeN4-tetrahedra (orange) 12 F.J. Pucher, S.R. Römer, F.W. Karau, W. Schnick, Chem. Eur. J.2010, 16, 7208.

  13. Nitridophosphates – BeP2N4 Theoretical Studies of BeP2N4 Calculated transition pressure: 24 GPa Potential superhard material 24 GPa ??? 13 F.J. Pucher, S.R. Römer, F.W. Karau, W. Schnick, Chem. Eur. J.2010, 16, 7208; W.Y. Ching, S. Aryal, P. Rulis, W. Schnick, Phys. Rev. B2011, 83, 155109-1.

  14. Whyworkon Oxonitridophosphates? PON SiO2 - ambient conditions: β-Cristobalite - 4.5 GPa, 750 °C: α-Quarz I  20 GPa  α-Quarz II - 2.5 GPa, 900 °C: Moganite However, all hithertoknown PON-modifications crystallize in knownSiO2-structures 14 J. M. Léger et. al. Phys. Chem. Miner. 2001, 28, 388; J. M. Léger et. al. J. Phys. Chem. Solids1999, 60, 145; C. Chateau et. al. Am. Mineral. 1999, 84, 207; J. Haines et. al. Acta Cryst. 1999, B55, 677.

  15. Oxonitridophosphates – H3P8O8N9 - Interruptedframeworkstructure (k = 0.47) - Hydrogen atompositionslocatedusing MAS-NMR 15 S.J. Sedlmaier, V.R. Celinski, J. Schmedt auf der Günne, W. Schnick, Chem. Eur. J.2012, 18, 4358.

  16. Oxonitridophosphates – d-PON Synthesis ofd-PON 12 GPa/1250°C "aPON"d-PON • - Network of all-sidevertexsharingtetrahedra • New AB2structure type withunprecedentednetworktopology • First polymorph of PON in a novelframework type • - Absence of hydrogen provenby FTIR- and MAS-NMR-spectroscopy 16 D. Baumann, S. J. Sedlmaier, W. Schnick, Angew. Chem.2012, 124, 4785; Angew. Chem. Int. Ed. 2012, 51, 4707.

  17. Oxonitridophosphates – d-PON Symmetry relationship to a predicted SiO2-polymorph Cmce t2 t2 (Aristotype) Bbbe2 P21/c (predicted for SiO2) (d-PON) • Structure of d-PON (right) crystallographically related to a predicted • SiO2-modification (left) through a common aristotype (top) 17

  18. II. Novel Binary Nitrides Highlights in Nitride and Diazenide chemistry

  19. Novel Binary Nitrides and Diazenides – an Overview Density Functional Study of Calcium Nitride: Refined Geometries and Prediction of High-Pressure Phases Group II Element Nitrides M3N2 Under Pressure: A Comparative Density Functional Study Ca3N2 and Mg3N2: Unpredicted High-Pressure Behavior of Binary Nitrides. Synthesis of Alkaline Earth Diazenides MAEN2 (MAE = Ca, Sr, Ba) by Controlled Thermal Decomposition of Azides under High Pressure High-Pressure Synthesis and Characterization of the Alkali Diazenide Li2N2 Reversible High-Pressure Phase Transition in LaN Materials Properties of Ultra-Incompressible Re2P

  20. What are Diazenides? [N=N]2- ~ νNN = 1304–1347 cm-1 H-N=N-H Diazene dNN = 1.21–1.25 Å • F. Holleman, E. Wiberg in Lehrbuch der Anorganischen Chemie, Vol. 102, de Gruyter, Berlin-New York, 2007; • N. Wiberg, G. Fischer, H. Bachhuber, Angew. Chem. Int. Ed.1977, 16, 780.

  21. Controlled thermal decomposition of ionic azides @ HP/HT-conditions 12 GPa/800°C Ca(N3)2 CaN2 + 2 N2 9 GPa/550°C Sr(N3)2 SrN2 + 2 N2 3 GPa/450°C Ba(N3)2 BaN2 + 2 N2 S.B. Schneider, R. Frankovsky, W. Schnick, Inorg. Chem.2012, 51, 2366

  22. Synthesis of MAE-Diazenides (MAE = Ca, Sr, Ba) CaN2 SrN2 BaN2 isotypic 12 GPa, 800°C 9 GPa, 550°C 3 GPa, 450°C I4/mmm (no. 139) I4/mmm (no. 139) C2/c (no. 15) dNN = 1.202(4) Å dNN = 1.239(4) Å dNN = 1.23(2) Å ~ ~ ~ νNN = 1376.9 cm-1νNN = 1378.9 cm-1νNN = 1375.9 cm-1 S.B. Schneider, R. Frankovsky, W. Schnick, Inorg. Chem.2012, 51, 2366

  23. Electronic Structure – CaN2 and SrN2 SrN2 metallic CaN2 SrN2 proven by conductivity measurements S.B. Schneider, R. Frankovsky, W. Schnick, Inorg. Chem.2012, 51, 2366

  24. Electronic Structure– CaN2and SrN2 about 50 % occupationofπ* CaN2 SrN2 DOS COHP (MAE-N) COHP (N-N) S.B. Schneider, R. Frankovsky, W. Schnick, Inorg. Chem.2012, 51, 2366

  25. Further MAE-Diazenides? Pre-condition: MAE(N3)2 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Ga Ge As Se Br Kr Rb Sr In Sn Sb Te I Xe Cs Ba Tl Pb Bi Po As Rn Alkali Diazenides? Alkali azides available

  26. Successful Synthesis of Li2N2 The First Alkali Diazenide 9 GPa/450°C 2 LiN3 Li2N2 + 2 N2 S.B. Schneider, R. Frankovsky, W. Schnick, Angew. Chem.2012, 124, 1909; Angew. Chem. Int. Ed.2012, 51, 1873.

  27. Successful Synthesis of Li2N2 The First Alkali Diazenide CN(Li+) = 4, 6, 8 CN([N2]2-) = 8 dNN = 1.301(3) Å S.B. Schneider, R. Frankovsky, W. Schnick, Angew. Chem.2012, 124, 1909; Angew. Chem. Int. Ed.2012, 51, 1873.

  28. Li2N2 – Spectroscopic and Electronic Analysis DOS COHP (N–N) [N2]2– vibration @ 1326.8 cm-1 Bandstructure: metallic IR-Spectrum proven by calculation of phononic DOS (R. Dronskwoski et al.) S.B. Schneider, R. Frankovsky, W. Schnick, Angew. Chem.2012, 124, 1909; Angew. Chem. Int. Ed.2012, 51, 1873.

  29. Li2N2 – Spectroscopic and Electronic Analysis DOS COHP (N–N) about 50 % occupationofπ* S.B. Schneider, R. Frankovsky, W. Schnick, Angew. Chem.2012, 124, 1909; Angew. Chem. Int. Ed.2012, 51, 1873.

  30. Summary • 8 accepted proposals for DESY or ESRF • 2 installed Multianvil presses at LMU • 20 publications in 2009-2012 period up to now • 8 PhD candidates/degrees Multianvil presses and DACs

  31. Thanks for your attention…

More Related