Detailed crystallographic analysis of the ice VI to ice XV hydrogen ordering phase transition

Salzmann, Christoph G.; Slater, Ben; Radaelli, P. G.; Finney, John; Shephard, Jacob J.; Rosillo‐Lopez, Martin; Hindley, James W.

doi:10.1063/1.4967167

Cited by 41 publications

(79 citation statements)

References 50 publications

(79 reference statements)

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“…46 The acid dopant introduces mobile point defects which speed up molecular reorientation processes and therefore facilitate hydrogen ordering. 46,[49][50][51][52] The ice V → ice XIII phase transition takes place upon isobaric cooling of ice V from its region of stability, but it can also be observed in a reversible fashion upon heating/cooling at ambient pressure with a phase transition temperature of 112 K. 50 Upon hydrogen-ordering, the space group changes from A2/a to P2 1 /a, which is why also the oxygen structure changes slightly. 46 This leads to 7 crystallographically distinct water molecules and 14 different types of hydrogen bonds of equal multiplicity.…”

Section: A Background: Ices Ih II V and Xiiimentioning

confidence: 99%

2D IR spectroscopy of high-pressure phases of ice

Tran

Cunha

Shephard

et al. 2017

The Journal of Chemical Physics

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We present experimental and simulated 2D IR spectra of some high-pressure forms of isotope-pure D 2 O ice and compare the results to those of ice Ih published previously [F. Perakis and P. Hamm, Phys. Chem. Chem. Phys. 14, 6250 (2012); L. Shi et al., ibid. 18, 3772 (2016)]. Ice II, ice V, and ice XIII have been chosen for this study, since this selection covers many aspects of the polymorphism of ice. That is, ice II is a hydrogen-ordered phase of ice, in contrast to ice Ih, while ice V and ice XIII are a hydrogen-disordered/ordered couple that shares essentially the same oxygen structure and hydrogenbonded network. For the transmission 2D IR spectroscopy, a novel method had to be developed for the preparation of ultrathin films (1-2 µm) of high-pressure ices with good optical quality. We also simulated 2D IR spectra based on molecular dynamics simulations connected to a vibrational exciton picture. These simulations agree with the experimental results in a semi-quantitative manner for ice II, while the same approach failed for ice V and ice XIII. From the perspective of 2D IR spectroscopy, ice II appears to be more inhomogeneously broadened than ice Ih, despite its hydrogen-order, which we attribute to the fact that ice II is structurally more complex with four distinguishable hydrogen bonds that mix due to exciton coupling. Ice V and ice XIII, on the other hand, behave as expected with the hydrogen-disordered case (ice V) being more inhomogenously broadened. Furthermore, in all hydrogen-ordered forms (ice II and ice XIII), cross peaks could be identified in the anisotropic 2D IR spectrum, whose signs reveal the relative direction of the corresponding excitonic states. Published by AIP Publishing. https://doi

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Section: A Background: Ices Ih II V and Xiiimentioning

confidence: 99%

2D IR spectroscopy of high-pressure phases of ice

Tran

Cunha

Shephard

et al. 2017

The Journal of Chemical Physics

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“…5-6, 9-11, 13-16 Much of the complexity arises from the fact that ice VI/XV consists of two interpenetrating hydrogen-bonded networks. [17][18][19] The formation of ice XV ordering which ultimately determines its space group symmetry. 5,[19][20] Intriguingly, the formation of ice XV is accompanied by an increase in volume which is due to an expansion in the crystallographic c direction.…”

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confidence: 99%

“…[17][18][19] The formation of ice XV ordering which ultimately determines its space group symmetry. 5,[19][20] Intriguingly, the formation of ice XV is accompanied by an increase in volume which is due to an expansion in the crystallographic c direction. 19 This means that the formation of ice XV is fastest at low pressures.…”

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Deep-Glassy Ice VI Revealed with a Combination of Neutron Spectroscopy and Diffraction

Rosu-Finsen

Amon

Armstrong

et al. 2020

J. Phys. Chem. Lett.

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The recent discovery of a low-temperature endotherm upon heating hydrochloric-acid doped ice VI has sparked a vivid controversy. The two competing explanations aiming to explain its origin range from a new distinct crystalline phase of ice to deep-glassy states of the well-known ice VI.Problems with the slow kinetics of deuterated phases have been raised, which we circumvent here entirely by simultaneously measuring the inelastic neutron spectra and neutron diffraction data of H2O samples. These measurements clearly confirm the deep-glassy ice VI scenario and rule out alternative explanations. Additionally, we show that the crystallographic model of D2O ice XV, the ordered counterpart of ice VI, also applies to the corresponding H2O phase. The discovery of deep-glassy ice VI now provides a fascinating new example of ultra-stable glasses which are encountered across a wide range of other materials. TOC GRAPHICS

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“…For pure ice VII, it is well-known that the hydrogen ordering to the antiferroelectric ice VIII takes place at around 0°C up to ~10 GPa (cf. Figure 1(a)) and with a hysteresis of only about 5.5 K. 28 So, compared to other hydrogen-ordering phase transitions, 1,5,20,[22][23][29][30][31] it is quite sharp and in fact the only one that proceeds from full hydrogen-disorder to full hydrogenorder according to diffraction. 12,[15][16] In line with previous studies, our pure D2O ice VIII displayed complete hydrogen order at 250 K and 4.43 GPa as indicated by the blue data point in To investigate the only partial hydrogen ordering upon cooling the ND4F-doped sample in more detail, all diffraction patterns starting from ice VII at 290 K down to 156 K were analyzed on the basis of the I41/amd structural model of ice VIII, which can be used to describe the higher symmetry ice VII but not the other way around.…”

Section: Bjerrum (O-h H-o and O…o) Defectsmentioning

confidence: 88%

Ammonium Fluoride as a Hydrogen-Disordering Agent for Ice

et al. 2019

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The removal of residual hydrogen disorder from various phases of ice with acid or base dopants at low temperatures has been a focus of intense research for many decades. As an antipode to these efforts, we now show using neutron diffraction that ammonium fluoride (NH4F) is a hydrogendisordering agent for the hydrogen-ordered ice VIII. Cooling its hydrogen-disordered counterpart ice VII doped with 2.5 mol% ND4F under pressure leads to a hydrogen-disordered ice VIII with ~31% residual hydrogen disorder illustrating the long-range hydrogen-disordering effect of ND4F.The doped ice VII could be supercooled by ~20 K with respect to the hydrogen-ordering temperature of pure ice VII after which the hydrogen-ordering took place slowly over a ~60 K temperature window. These findings demonstrate that ND4F-doping slows down the hydrogenordering kinetics quite substantially. The partial hydrogen order of the doped sample is consistent with the antiferroelectric ordering of pure ice VIII. Yet, we argue that local ferroelectric domains must exist between ionic point defects of opposite charge. In addition to the long-range effect of NH4F-doping on hydrogen-ordered water structures, the design principle of using topological charges should be applicable to a wide range of other 'ice-rule' systems including spin ices and related polar materials. IntroductionWater's phase diagram has been explored for more than a century leading to the discovery of 17 crystallographically distinct phases of ice so far. [1][2][3][4][5] The water molecules in the various phases of ice are fully hydrogen-bonded which gives rise to 4-fold connected networks following the 'twoin-two-out' ice rules with respect to the donation and acceptance of hydrogen bonds. 6-8 Based on this building principle, a wide range of network topologies can be observed ranging from the high-symmetry ice Ih network with only six-membered rings and the highly complex ice V/XIII network to the two interpenetrating individual networks of ice VII/VIII. [6][7][8] Within the constraints of the ice rules, 9 the water molecules can display orientational disorder and such phases are categorized as hydrogen-disordered. In fact, all phases of ice that can be crystallized from liquid water display hydrogen disorder as can be seen in Figure 1(a). In the case of ices Ih, Isd, IV, VI, VII and XII, full hydrogen disorder is observed in neutron diffraction in the form of half-occupied deuterium sites. [10][11][12][13] Ices III and V on the other hand display partial hydrogen order and some of the fractional occupancies deviate significantly from ½. 13 As required by the third law of thermodynamics, the various hydrogen-disordered phases are expected to transform to their corresponding hydrogen-ordered counterparts upon cooling as long-range orientational order of the water molecules is established. Figure 1(b) shows the crystal structures of the hydrogen-disordered ice VII and its hydrogen-ordered counterpart ice VIII.

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Detailed crystallographic analysis of the ice VI to ice XV hydrogen ordering phase transition

Cited by 41 publications

References 50 publications

2D IR spectroscopy of high-pressure phases of ice

2D IR spectroscopy of high-pressure phases of ice

Deep-Glassy Ice VI Revealed with a Combination of Neutron Spectroscopy and Diffraction

Ammonium Fluoride as a Hydrogen-Disordering Agent for Ice

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