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Bertin A, Kiefer L, Becker P, Bohatý L, Braden M. Rotational phase transitions in antifluorite-type osmate and iridate compounds. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:245402. [PMID: 38437717 DOI: 10.1088/1361-648x/ad2fef] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 03/04/2024] [Indexed: 03/06/2024]
Abstract
We present temperature-dependent single-crystal diffraction results on seven antifluorite-typeA2MeX6compounds withMe= Os or Ir: K2OsCl6,A2OsBr6withA= K, Rb, Cs and NH4, and K2IrX6withX= Cl and Br. The structural transitions in this family arise fromMeX6octahedron rotations that generate a rich variety of symmetries depending on the rotation axis and stacking schemes. In order to search for local distortions in the high-symmetry phase we perform refinements of anharmonic atomic displacement parameters with comprehensive data sets. Even at temperatures close to the onset of structural distortions, these refinements only yield a small improvement indicating only small anharmonic effects. The phase transitions in these antifluorites are essentially of displacive character. However, some harmonic displacement parameters are very large reflecting soft phonon modes with the softening covering large parts of the Brillouin zone. The occurrence of the rotational transitions in the antifluorite-type family can be remarkably well analyzed in terms of a tolerance factor of ionic radii.
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Affiliation(s)
- A Bertin
- Institute of Physics II, University of Cologne, 50937 Cologne, Germany
| | - L Kiefer
- Institute of Physics II, University of Cologne, 50937 Cologne, Germany
| | - P Becker
- Sect. Crystallography, Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany
| | - L Bohatý
- Sect. Crystallography, Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany
| | - M Braden
- Institute of Physics II, University of Cologne, 50937 Cologne, Germany
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2
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Kohlmann H. Rotationally ordered ammonium cations in the crystal structure of (NH
4
)
2
OsBr
6. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202100375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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3
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Autillo M, Wilson RE. Phase Transitions in Tetramethylammonium Hexachlorometalate Compounds (TMA)
2
MCl
6
(M = U, Np, Pt, Sn, Hf, Zr). Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700764] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Matthieu Autillo
- Chemical Sciences and Engineering Division Argonne National Laboratory 60439 Argonne Illinois USA
| | - Richard E. Wilson
- Chemical Sciences and Engineering Division Argonne National Laboratory 60439 Argonne Illinois USA
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Kume Y, Amino D, Asaji T. Isotope effect on the temperature dependence of the 35Cl NQR frequency in (NH4)2RuCl6. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.03.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Punkkinen M, Ylinen EE. Deuteron spin-lattice relaxation in ammonium hexachlorometallates. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2009; 35:172-179. [PMID: 18693087 DOI: 10.1016/j.ssnmr.2008.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Accepted: 06/30/2008] [Indexed: 05/26/2023]
Abstract
Deuteron spin-lattice relaxation via the motion-dependent part of the electric quadrupole interaction is discussed in partly and fully deuterated ammonium ions of ammonium hexachlorometallates. The dominant motion at temperatures T>50K is normally 120 degrees reorientations of the ammonium ions. In some hexachlorometallates the instantaneous equilibrium directions of the nitrogen-hydrogen vectors make a certain angle Delta with the metal-nitrogen vectors and they appear in groups of six near each metal-hydrogen vector. Each N-D vector jumps between the six directions of one group and this motion (called limited jumps) dominates the deuteron relaxation at lower temperatures. In some samples one direction of each group seems to become more populated than the others when the deuteration degree exceeds a certain value and the ammonium ions become ordered. A model is derived for the relaxation rate in the absence of tunnelling splittings, which includes the effects of reorientations and limited jumps also in the ordered structure, where the limited-jump rate of a N-D vector to the preferred direction, r(p), differs from that to the nonpreferred direction, r(n). The obtained relaxation rate depends, in addition to the angle Delta, also on the ratio d=r(n)/r(p). The effect of d is discussed and estimates for it are presented on the basis of earlier experiments. The recent model for the deuteron relaxation in NH(3)D(+) ions, including the effect of proton tunnelling, is shortly reviewed. At lowest temperatures the motional rates can be dominated by corresponding incoherent tunnelling and the rate of the incoherent tunnelling contributing to limited jumps is argued to be clearly larger than that of the incoherent tunnelling contributing to approximately 120 degrees rotations.
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Affiliation(s)
- M Punkkinen
- Department of Physics, Wihuri Physical Laboratory, University of Turku, Turku, Finland.
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Birczyński A, Ylinen EE, Punkkinen M, Szymocha AM, Lalowicz ZT. Deuteron spin-lattice relaxation in partly and fully deuterated (NH(4))(2)PdCl(6). SOLID STATE NUCLEAR MAGNETIC RESONANCE 2008; 34:77-85. [PMID: 18585902 DOI: 10.1016/j.ssnmr.2008.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Revised: 05/13/2008] [Accepted: 05/13/2008] [Indexed: 05/26/2023]
Abstract
Deuteron spin-lattice relaxation and spectra were studied in partially and fully deuterated (NH(4))(2)PdCl(6) in the temperature range 5-300K. The relaxation rate maximum was observed at 45K in (ND(4))(2)PdCl(6). Its value is reduced due to limited jumps by about 33% relative to the theoretical value expected for threefold reorientations. Limited jumps correspond to an N-D vector jumping between six directions on a cone around a Pd-N vector, the angle between the N-D and Pd-N vectors being denoted Delta. This motion makes a part of the quadrupole interaction ineffective in relaxation thus reducing the maximum rate at 45K. The observed reduction leads to the value Delta=21( composite function). Limited jumps are quenched to a large extent at the order-disorder phase transition and consequently a decrease is observed in the rate. Below the transition ND(4)(+) ions reorient between the tetrahedral orientations of the ordered phase, therefore the quadrupole interaction has the full relaxing efficiency. In the 10% deuterated sample the temperature of the rate maximum is shifted to 35K and below 20K the rate itself is one order of magnitude larger than in (ND(4))(2)PdCl(6). The increase is related to (1) the absence of the order-disorder phase transition and (2) to the enhanced mobility of NH(3)D(+) because of its electric dipole moment. Limited jumps are claimed to be the dominant relaxation mechanism below 20K. The relaxation in the disordered 30% deuterated sample is quite similar to that in 10% sample. The 50% and 70% deuterated samples undergo a transition to the ordered phase. The relaxation is biexponential with the characteristic rates somewhat smaller than those in (ND(4))(2)PdCl(6), but approaching them with increasing deuteration. This variation can be explained with different mobilities and varying relative numbers of the various isotopomers NH(4-n)D(n)(+), n=1-4.
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Affiliation(s)
- A Birczyński
- H. Niewodniczański Institute of Nuclear Physics of PAS, ul. Radzikowskiego 152, 31-342 Kraków, Poland
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Birczyński A, Ylinen EE, Punkkinen M, Prager M, Szymocha AM, Lalowicz ZT. Deuteron NMR relaxation, spectra, and evidence for the order-disorder phase transition in (ND4)2PtCl6. J Chem Phys 2008; 128:184510. [DOI: 10.1063/1.2919568] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Birczyński A, Lalowicz Z, Szymocha A, Punkkinen M, Ylinen E, Vuorimäki A. Deuteron NMR spin–lattice relaxation of NH3D+ ions in partially deuterated (NH4)2SnCl6 and NH4ClO4. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2006.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Birczyński A, Lalowicz ZT, Olejniczak Z, Stoch G, Petelenz B. Deuteron NMR spectra of ammonium ion isotopomers at low temperatures. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2005; 28:142-59. [PMID: 16081254 DOI: 10.1016/j.ssnmr.2005.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 07/06/2005] [Accepted: 07/08/2005] [Indexed: 05/03/2023]
Abstract
Partially deuterated ammonium compounds contain ammonium ion isotopomers with relative abundances given by the binomial distribution of protons and deuterons. All isotopomers with deuterons contribute characteristic deuteron NMR spectra at 5K. Experimental NMR spectra were separated and respective contributions of isotopomers were determined. The derived contributions agree with expected values for a given deuteration in the case of ammonium hexafluorophosphate. In ammonium hexachlorotellurate both NH2D2+ and about 50% of NH3D+ ions are rigid, while the remaining NH3D+ perform limited jumps. NHD3+ and ND4+ ions undergo tunnelling rotation, NH3D+ ions perform either jumps about C2 axis or limited jumps, but some stay rigid in ammonium hexachlorostannate. NH2D2+, NHD 3+ and ND4+ undergo rotational tunnelling. In the case of ammonium perchlorate, the NH3D+ ions perform either jumps about C3 axis or limited jumps whilst some remain rigid. Very low values of activation energies were derived for all spectral components from the temperature dependence of their spectra, up to about 20K, which indicates an incoherent tunnelling nature of the observed dynamic processes. The diverse mobility of NH3D+ ions appears to be the most interesting and new feature.
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Affiliation(s)
- A Birczyński
- H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Kraków, Poland
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Birczyński A, Lalowicz Z, Łodziana Z. Rotational barriers in ammonium hexachlorometallates as studied by NMR, tunnelling spectroscopy and ab initio calculations. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2003.12.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Prager M, Schiebel P, Grimm H. Rotational tunneling of NH4 and NH3D and dipolar interaction in (NH3.6D0.4)2PtCl6. J Chem Phys 2002. [DOI: 10.1063/1.1477185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Matsuo T, Kohno K, Inaba A, Mochida T, Izuoka A, Sugawara T. Calorimetric study of proton tunneling in solid 5-bromo-9- hydroxyphenalenone and deuteration-induced phase transitions in its deuteroxy analog. J Chem Phys 1998. [DOI: 10.1063/1.476455] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Kume Y, Muraoka H, Yamamuro O, Matsuo T. Deuteration-induced phase transition in ammonium hexachloroplumbate. J Chem Phys 1998. [DOI: 10.1063/1.475806] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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