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Structural Studies of Metal-Hydrogen Interactions in Solid-State Metal Hydrides

Structural Studies of Metal-Hydrogen Interactions in Solid-State Metal Hydrides. Yaroslav Filinchuk on behalf of the Laboratory of Crystallography University of Geneva. SINQ Users’ Meeting PSI , 27 Jan 200 5. LaD 2+x. Calculated atom relaxations (Å) around

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Structural Studies of Metal-Hydrogen Interactions in Solid-State Metal Hydrides

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  1. Structural Studies of Metal-Hydrogen Interactionsin Solid-State Metal Hydrides Yaroslav Filinchuk on behalf of the Laboratory of CrystallographyUniversity of Geneva SINQ Users’ Meeting PSI, 27Jan 2005

  2. LaD2+x Calculated atom relaxations (Å) around tetrahedral hydrogen vacancy in La32H95 Refined average D-atom displacements (e)in octahedral interstices as a functionof refined composition LaD2+x Renaudin et al., 2004 HRPT Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  3. ErNi3: HRPT, λ~ 1.15 Å Single-crysal-likerefinement from powder data ! Filinchuk et al., 2004 R-3m centro Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  4. β1-ErNi3D1.23(1): HRPT, λ~ 1.49 Å Deuteration on site, or in-situ Filinchuk et al., 2004 R3m non-centro Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  5. Alloy ErNi3 HRPT Filinchuk et al., 2004 Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  6. b1-deuteride ErNi3D1.23 b1-deuteride ErNi3D1.23 Symmetry loss Anisotropic cell expansion along c AB2 block is filled with deuterium Filinchuk et al., 2004 Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  7. b2-deuteride ErNi3D1.97 Trigonal prism [NiD3] Isotropic cell expansion AB5 block is partially filled with D Filinchuk et al., 2004 Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  8. Tetrahedral [NiD4] : similar to LaMg2NiD7& Mg2NiD4 different from ErCo3Dx & YCo3Dx g-deuteride ErNi3D3.75 Anisotropic cell expansion along a AB5 block is filled with deuterium Filinchuk et al., 2004 Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  9. LaNi3B→LaNi3BD2.5-3Imma, oI20→Cmcm, oC80 Filinchuk et al., 2004 LaNi3B Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  10. HRPT The unit cell is doubled along a and b LaNi3BH2.7 Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  11. D-Ni bond-valence sums are equal to 1 for each of 4 D-atom sites La3+B0[Ni3D3]3– Two dimentionalframeworkNi-D Filinchuk et al., 2004 HRPT Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  12. Temperature dependence of the cubic cell parameter and of deuterium occupancies in ZrTi2D4.3 (from DMC data) Tokaychuk et al., 2004 ZrTi3 Fd-3m Zr2Ti2 Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  13. Energy differencebetweenthe twodeuterium sitesin ZrTi2Dx 127 meV Dynamical hydrogen disorder Metal to hydrogen interactions are important (!) Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  14. Renaudin et al., 2004 DMC Phase transitions in alkali borohydrides Ordering of BD4- anion: Fm-3mtoP42 /nmc Badger’s rule Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  15. Conditions Filinchuk et al., 2004 DMC ErCo3D4.0 ErCo3 ErCo3D1.6 vacuum 4.978(2) 24.227(18) 520.0(5) • phase diagram • cell expansion • deuterium content Little portions of D2 let in 4.979(4) 24.25(3) 520.8(9) 4.9837(16) 25.463(17) 547.7(4) 1.07(4) 4.9859(9) 25.626(10) 551.7(2)1.14(3) 4.9871(8) 25.690(9) 553.3(2)1.20(3) 4.9894(9) 25.834(9) 557.0(2)1.27(3) 4.9910(9) 25.963(8) 560.1(2)1.36(3) 4.9910(9) 26.018(8) 561.3(2)1.38(4) 4.9914(10) 26.032(9) 561.7(2)1.38(3) 5.217(9) 26.21(9) 617(3) 2.5 bar D2 4.9920(10) 26.017(9) 561.5(3)1.37(3) 5.213(5) 26.16(4) 616(1) 2.5 bar D2 4.9924(13) 25.997(11) 561.2(3)1.35(4) 5.210(3) 26.14(3) 614.5(8) 3.0 bar D2 4.996(4) 25.94(3) 560.7(10)1.35 5.211(2) 26.07(2) 613.2(5) 3.75 4.0 bar D2 5.2189(8) 26.044(7) 614.3(2) 3.84(6) 6 bar D2 5.2250(8) 26.071(7) 616.4(2) 3.91(6) 9 bar D2 5.2277(8) 26.098(7) 617.7(2) 4.13(5) 12 bar D2 5.2298(7) 26.115(6) 618.6(2) 4.17(5) 16 bar D2 5.2318(8) 26.134(7) 619.5(2) 4.20(6) 16 bar, 25°C 5.2356(7) 26.202(6) 622.0(2) 4.30(5) ErCo3-D2 : in-situ NPD, 60°C, 0-16 bar Accurate structures from HRPT data Magnetic structures: DMC (1.5-210K) Co-Co exchange interactions are correlated with Co-D bonding Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  16. Diffraction at SINQ • HRPT • detailed investigation of complex structures • in-situ NPD (tiny structural changes) • DMC • structure dynamics (hydrogen motion) • in-situ NPD (complex phase diagrams) • magnetic structures (M-M interactions) • high-resolution NPD (phase transitions) Complementary • Synchrotron powder & • single crystal diffraction • INS & Raman spectrosc. • magnetic & el. properties • ab-initio calculations Techniques used to study Metal-Hydrogen Interactions Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

  17. This work has been partially performed at the Swiss Spallation Neutron Source SINQ, Paul Scherrer Institute, Villigen, SwitzerlandWe acknowledge the help of Denis Sheptyakov, Aziz Daoud-Aladine and Lukas Keller Y. FilinchukSINQ Users’ Meeting, 27 Jan 2005

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