Structure of ice III

Kamb, Barclay; Prakash, A.

doi:10.1107/s0567740868004231

Cited by 73 publications

(58 citation statements)

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“…We confirmed that the phase at 3 GPa and 80 K is ice VIII by its characteristic rotational, translational, and stretching Raman spectra; 16 in the case of x-ray diffraction, we confirmed by its characteristic hkl indeces ͑d spacings͒. 3,17 The diffraction and spectroscopic data were collected as the sample was compressed in steps to ϳ20 GPa. We paid special attention to isothermal compression at 80 K. The experimental paths are shown schematically in Fig.…”

Section: Experimental Methodssupporting

confidence: 62%

“…At least 15 different stable and metastable forms ͓e.g., ice I h ,I c -XII, low-density amorphous ice ͑LDA͒, and high-density amorphouse ice ͑HDA͔͒ have been identified so far, but many are still not fully characterized within their thermodynamic and kinetic stability ranges. [1][2][3][4][5] Our understanding of the phase diagram of ice is incomplete, especially at low temperature and high pressure. Above ϳ2 GPa, dense ices such as ices VII and VIII form, polymorphs that can be understood as interpenetration of low-pressure ice structures, and at very high-pressures ͑ϳ60 GPa͒ symmetric ice X phase forms.…”

Section: Introductionmentioning

confidence: 99%

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High-pressure x-ray diffraction and Raman spectroscopy of ice VIII

Yoshimura

Stewart

Somayazulu

et al. 2006

The Journal of Chemical Physics

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In situ high-pressure/low-temperature synchrotron x-ray diffraction and optical Raman spectroscopy were used to examine the structural properties, equation of state, and vibrational dynamics of ice VIII. The x-ray measurements show that the pressure-volume relations remain smooth up to 23 GPa at 80 K. Although there is no evidence for structural changes to at least 14 GPa, the unit-cell axial ratio c∕a undergoes changes at 10–14 GPa. Raman measurements carried out at 80 K show that the νTzA1g+νTx,yEg lattice modes for the Raman spectra of ice VIII in the lower-frequency regions (50–800cm−1) disappear at around 10 GPa, and then a new peak of ∼150cm−1 appears at 14 GPa. The combined data provide evidence for a transition beginning near 10 GPa. The results are consistent with recent synchrotron far-IR measurements and theoretical calculations. The decompressed phase recovered at ambient pressure transforms to low-density amorphous ice when heated to ∼125K.

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Section: Experimental Methodssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

High-pressure x-ray diffraction and Raman spectroscopy of ice VIII

Yoshimura

Stewart

Somayazulu

et al. 2006

The Journal of Chemical Physics

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“…In Fig. 6 Kamb's data (17,18) is replotted along with the frequencies of vOD(HDO) in ethylene oxide hydrate, ice V (15) and ice VI (16) which are plotted against the weighted mean hydrogen bond length in these phases (1). As Kanlb and Prakash showed (17) the four points for ice I1 and one of the points for ice IX lie close to a line with a slope of 510 cm-' A-'.…”

Section: Absorption By the Wafermentioning

confidence: 99%

The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate at 100°K between 4000 and 360 cm⁻¹

Bertie¹,

Othen²

1973

Can. J. Chem.

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The infrared spectra of characterized samples of ethylene oxide hydrate made from 100% H 2 0 , 99.7% D 2 0 , and several dilute isotopic solutions, are presented between 4000 and 360 cm-I. The similarity between the absorption by the watcr ~nolecules in the hydrate and in ice I is discussed. The frequency and halfwidth of tlie O H and O D stretching modes of isolated HDO molecules in tlie hydrate are related to those in the disordered ice phases; the frequencies correlate rather well with the weighted-mean hydrogen bond lengths in these phases.The ethylene oxide vibrations show sharp, single-line absorption. The only exceptions are the ringbreathing mode which appears as a doi~blet, separated by 2 cni-', with m~~c h weaker absorption about 13 cm-' away on either side, and the ring deformation modes which interact with the vK(H20) niodes. The possible causes of this behavior are disci~ssed, but no firm conclusions can be drawn. The sharpness of tlie absorption by enclathrated ctliylene oxide, compared to that by liquid ethylene oxide, is brietly discussed in the light of modern theories of bandshapes in liquids. dans l'hydrate ont ete reliees a celles des phases dCsordonnCes de la glace ; la correlation dcs frtqi~ences est plut8t bonne avec la nioyenne pondCrCe dcs liaisons hydrogcne dans ces phases. Les vibrations de

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“…The most promising indexing scheme is given by the symmetry space group P4 1 2 1 2. This symmetry space group is uniquely inherent to ice III and ice IX, which differ in the degree of order in their proton sublattices [20][21][22][23]. As in ice XII, twelve water molecules inhabit the tetragonal unit cell of ice III/IX.…”

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confidence: 99%

Ice XII in Its Second Regime of Metastability

et al. 2000

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We present neutron powder diffraction results which give unambiguous evidence for the formation of the recently identified new crystalline ice phase [4], labeled ice XII, at completely different conditions. Ice XII is produced here by compressing hexagonal ice I h at T = 77, 100, 140 and 160 K up to 1.8 GPa. It can be maintained at ambient pressure in the temperature range 1.5 < T < 135 K. High resolution diffraction is carried out at T = 1.5 K and ambient pressure on ice XII and accurate structural properties are obtained from Rietveld refinement. At T = 140 and 160 K additionally ice III/IX is formed. The increasing amount of ice III/IX with increasing temperature gives an upper limit of T ≈ 150 K for the successful formation of ice XII with the presented procedure.Although, water has been extensively studied both experimentally and theoretically it still rewards us with new and unexpected properties. This has been demonstrated recently by (i) the detection of polyamorphism [1][2][3] and (ii) the discovery of a new crystalline phase (ice XII) [4,5]. Having been observed in different regions of water's phase diagram the two phenomena were originally thought to be disconnected (Figure 1). The phenomenon of polyamorphism, i.e. the existence of two distinct amorphous phases, is still lacking a comprehensive understanding [6]. Although polyamorphism is equally observed in other substances particularly interesting explanations have been put forward for water. These ideas are based on computer simulations [7] and link polyamorphism to particularities of the supercooled liquid like phase segregation and a second critical point. Due to homogeneous crystallization supercooled water is experimentally inaccessible in the region where these phenomena are expected. The hypotheses must, therefore, be checked indirectly, e.g. by establishing the glassy character of the amorphous phases. The formation of the highdensity amorphous ice (HDA) -achieved by compressing crystalline hexagonal ice I h at temperatures below 150 K to pressures exceeding 1 GPa (Fig. 1) -has received particular attention in this context [7][8][9].So far, the formation of HDA from ice I h has been reported as a well-defined transition channel. The contamination of the amorphous samples by crystalline impurities has been granted little attention [10][11][12]. Only recently [13][14][15] strong experimental indications have become available which imply that all these contaminations correspond to ice XII. As ice XII was originally observed in a completely different region of water's phase diagram this shows that it is a rather prolific phase of water. Moreover, the co-production of ice XII has, as we will argue in the conclusions, far reaching implications for the I h to HDA transformation and, thus, on the origin of water's polyamorphism.In this letter we show that the structure of ice XII produced at low temperatures is definitely identical with the phase characterized by Lobban et al.[4] at higher temperatures. Furthermore, we find that no continuous connec...

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Structure of ice III

Cited by 73 publications

References 7 publications

High-pressure x-ray diffraction and Raman spectroscopy of ice VIII

High-pressure x-ray diffraction and Raman spectroscopy of ice VIII

The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate at 100°K between 4000 and 360 cm⁻¹

Ice XII in Its Second Regime of Metastability

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Structure of ice III

Cited by 73 publications

References 7 publications

High-pressure x-ray diffraction and Raman spectroscopy of ice VIII

High-pressure x-ray diffraction and Raman spectroscopy of ice VIII

The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate at 100°K between 4000 and 360 cm−1

Ice XII in Its Second Regime of Metastability

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The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate at 100°K between 4000 and 360 cm⁻¹