Zhang, P.*; Tang, X.*; Wang, Y.*; Wang, X.*; Gao, D.*; Li, Y.*; Zheng, H.*; Wang, Y.*; Wang, X.*; Fu, R.*; et al.
Journal of the American Chemical Society, 142(41), p.17662 - 17669, 2020/10
Solid-state topochemical polymerization (SSTP) is a promising method to construct functional crystalline polymeric materials, but in contrast to various reactions that happen in solution, only very limited types of SSTP reactions are reported. Diels-Alder (DA) and dehydro-DA (DDA) reactions are textbook reactions for preparing six-membered rings in solution but are scarcely seen in solid-state synthesis. Here, using multiple cutting-edge techniques, we demonstrate that the solid 1,4-diphenylbutadiyne (DPB) undergoes a DDA reaction under 10-20 GPa with the phenyl as the dienophile. The crystal structure at the critical pressure shows that this reaction is "distance-selected". The distance of 3.2 between the phenyl and the phenylethynyl facilitates the DDA reaction, while the distances for other DDA and 1,4-addition reactions are too large to allow the bonding. The obtained products are crystalline armchair graphitic nanoribbons, and hence our studies open a new route to construct the crystalline carbon materials with atomic-scale control.
Bauer, R.*; Tse, J. S.*; Komatsu, Kazuki*; Machida, Shinichi*; Hattori, Takanori
Nature, 585(7825), p.E9 - E10, 2020/09
Pressure-induced structural transformations in deuterated crystalline ice-Ih were studied in-situ at 100 K using neutron diffraction. Very long relaxation time was allowed between small pressure increments to promote transformations to the thermodynamic stable high pressure crystalline phases. The results contradict a recent report in which measurements under similar temperature and pressure environment show successive crystal-to-crystal transformations (Tulk, et.al., Nature 2019). Instead, ice Ih was found to transform partially to an amorphous form (high density amorphous, HDA) at 1.0 GPa and then ice VII started to emerge at 1.5 GPa, a pressure substantially lower than all earlier studies. During this pressure interval, crystalline ice Ih or ice VII co-exist with HDA. The ice VII formed is stable upon pressure release down to 0.1 GPa. The very low compression rate has a profound effect on the crystallinity in the amorphous regime. Gathering all the existing experimental evidences allows an unambiguous description of the phenomenon of pressure induced amorphization. The onset of the phase transition is triggered by a shear instability of the ice lattice. The co-existence ice VII with HDA, instead of the equilibrium thermodynamic stable and proton-ordered ice-VIII under the same pressure-temperature condition reveals at low temperature there is insufficient thermal energy to overcome the substantial geometrical rearrangement from a single proton disordered H-bond network to an interpenetrating proton ordered H-bond crystalline network. Thus, leaving the proton disordered H-network intact. The analysis shows unequivocally that the structure obtained from the compression of ice is controlled by kinetics and dependent on the temperature.
Saito, Hiroyuki*; Machida, Akihiko*; Iizuka, Riko*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; Sato, Toyoto*; Orimo, Shinichi*; Aoki, Katsutoshi*
Scientific Reports (Internet), 10, p.9934_1 - 9934_8, 2020/06
Neutron powder diffraction profiles were collected for iron deuteride (FeDx) while the temperature decreased from 1023 to 300 K for a pressure range of 4-6 GPa. The ' deuteride with a double hexagonal close-packed (dhcp) structure, which coexisted with other stable or metastable deutrides at each temperature and pressure condition, formed solid solutions with a composition of FeD at 673 K and 6.1 GPa and FeD at 603 K and 4.8 GPa. Upon stepwise cooling to 300 K, the D-content x increased to a stoichiometric value of 1.0 to form monodeuteride FeD. In the dhcp FeD at 300 K and 4.2 GPa, dissolved D atoms fully occupied the octahedral interstitial sites, slightly displaced from the octahedral centers in the dhcp metal lattice, and the dhcp sequence of close-packed Fe planes contained hcp-stacking faults at 12%. Magnetic moments with 2.11 0.06 B/Fe-atom aligned ferromagnetically in parallel on the Fe planes.
Komatsu, Kazuki*; Klotz, S.*; Machida, Shinichi*; Sano, Asami; Hattori, Takanori; Kagi, Hiroyuki*
Proceedings of the National Academy of Sciences of the United States of America, 117(12), p.6356 - 6361, 2020/03
Above 2 GPa the phase diagram of water simplifies considerably and exhibits only two solid phases up to 60 GPa, ice VII and ice VIII. The two phases are related to each other by hydrogen ordering, with the oxygen sub-lattice being essentially the same. Here we present neutron diffraction data to 15 GPa which reveal that the rate of hydrogen-ordering at the ice VII-VIII transition decreases strongly with pressure to reach time scales of minutes at 10 GPa. Surprisingly, the ordering process becomes more rapid again upon further compression. We show that such an unusual change in transition rate can be explained by a slowing-down of the rotational dynamics of water molecules with a simultaneous increase of translational motion of hydrogen under pressure, as previously suspected. The observed crossover in the hydrogen dynamics in ice is likely the origin of various hitherto unexplained anomalies of ice VII in the 10-15 GPa range reported by Raman spectroscopy, X-ray diffraction, and proton conductivity.
Komatsu, Kazuki*; Klotz, S.*; Nakano, Satoshi*; Machida, Shinichi*; Hattori, Takanori; Sano, Asami; Yamashita, Keishiro*; Irifune, Tetsuo*
High Pressure Research, 40(1), p.184 - 193, 2020/02
A new high pressure cells for neutron diffraction experiments using nano-polycrystalline anvil is presented. The cell design, off-line pressure generation tests and a gas-loading procedure for this cell are described. The performance is illustrated by powder neutron diffraction patterns of ice VII to 82 GPa. We also demonstrate the feasibility of single crystal neutron diffraction experiments of FeO at ambient conditions using this cell and discuss the current limitation and future developments.
Komatsu, Kazuki*; Machida, Shinichi*; Noritake, Fumiya*; Hattori, Takanori; Sano, Asami; Yamane, Ryo*; Yamashita, Keishiro*; Kagi, Hiroyuki*
Nature Communications (Internet), 11(1), p.464_1 - 464_5, 2020/02
Water freezes below 0C at ambient pressure ordinarily to ice I, with hexagonal stacking sequence. Under certain conditions, ice with a cubic stacking sequence can also be formed, but ideal ice I without stacking-disorder has never been formed until recently. Here we demonstrate a route to obtain ice I without stacking-disorder by degassing hydrogen from the high-pressure form of hydrogen hydrate, C, which has a host framework isostructural with ice I. The stacking-disorder free ice I is formed from C via an intermediate amorphous or nano-crystalline form under decompression, unlike the direct transformations occurring in ice XVI from neon hydrate, or ice XVII from hydrogen hydrate. The obtained ice I shows remarkable thermal stability, until the phase transition to ice I at 250 K, originating from the lack of dislocations. This discovery of ideal ice I will promote understanding of the role of stacking-disorder on the physical properties of ice as a counter end-member of ice I.
Klotz, S.*; Komatsu, Kazuki*; Polian, A.*; Machida, Shinichi*; Sano, Asami; Iti, J.-P.*; Hattori, Takanori
Physical Review B, 101(6), p.064105_1 - 064105_6, 2020/02
Manganese oxide (MnO) is a prototype of an antiferromagnetic Mott-insulator. Here we investigate the interplay of magnetic ordering and lattice distortion across the Nel temperature under pressure using neutron and X-ray diffraction. We find an increase of with a rate of = +4.5(5) K/GPa, an increase of the rhombohedral distortion by = +0.018/GPa, as well as a volume striction which is insensitive to pressure. These results allow to retrieve the dependence of the coupling constants and on interatomic distances and compare it to first-principles predictions. Antiferromagnetic diffuse scattering was observed up to 1.2 , and long-range magnetic order appears at room temperature at 42 GPa.
Urakawa, Satoru*; Inoue, Toru*; Hattori, Takanori; Sano, Asami; Kohara, Shinji*; Wakabayashi, Daisuke*; Sato, Tomoko*; Funamori, Nobumasa*; Funakoshi, Kenichi*
Minerals (Internet), 10(1), p.84_1 - 84_13, 2020/01
The structure of hydrous amorphous SiO is fundamental to investigate the effects of water on the physicochemical properties of oxide glasses and magma. The hydrous SiO glass with 13 wt.% DO was synthesized under high-pressure and high-temperature conditions and its structure was investigated by small angle X-ray scattering, X-ray diffraction, and neutron diffraction experiments at pressures of up to 10 GPa and room temperature. This hydrous glass is separated into a SiO rich major phase and a DO rich minor phase. Medium-range order of the hydrous glass shrinks compared to the anhydrous SiO glass due to disruption of SiO linkage by formation of Si-OD deuterioxyl, while the pressure response is similar. Most of DO molecules are in the small domains and hardly penetrate into SiO major phase.
Yamashita, Keishiro*; Komatsu, Kazuki*; Hattori, Takanori; Machida, Shinichi*; Kagi, Hiroyuki*
Acta Crystallographica Section C; Structural Chemistry (Internet), 75(12), p.1605 - 1612, 2019/12
A crystal structure of a high-pressure phase of magnesium chloride hexahydrate (MgCl 6HO-II) and its deuterated counterpart (MgCl 6DO-II) have been identified for the first time by in-situ single-crystal X-ray and powder neutron diffraction. The crystal structure was analyzed by the Rietveld method for the neutron diffraction pattern based on the initial structure determined by single-crystal X-ray diffraction. This high-pressure phase has a similar framework to that in the known ambient-pressure phase, but exhibits some structural changes with symmetry reduction caused by a subtle modification in the hydrogen-bond network around the Mg(HO) octahedra. These structural features reflect the strain in the high-pressure phases of MgCl hydrates.
Machida, Akihiko*; Saito, Hiroyuki*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; Sato, Toyoto*; Orimo, Shinichi*; Aoki, Katsutoshi*
Scientific Reports (Internet), 9(1), p.12290_1 - 12290_9, 2019/08
Hexagonal close-packed iron hydride, hcp FeHx, is absent from the conventional phase diagram of the Fe-H system, although hcp metallic Fe exists stably over extensive temperature () and pressure () conditions, including those corresponding to the Earth's inner core. X-ray and neutron diffraction measurements at temperatures ranging from 298 to 1073 K and H pressures ranging from 4 to 7 GPa revealed that the hcp hydride was formed for FeH compositions when . Hydrogen atoms occupied the octahedral interstitial sites of the host metal lattice both partially and randomly. The hcp hydride exhibited a H-induced volume expansion of 2.48(5) /H-atom, which was larger than that of the face-centered cubic (fcc) hydride. The hcp hydride showed an increase in with , whereas the fcc hydride showed a corresponding decrease. The present study provides guidance for further investigations of the Fe-H system over an extensive -- region.
Klotz, S.*; Casula, M.*; Komatsu, Kazuki*; Machida, Shinichi*; Hattori, Takanori
Physical Review B, 100(2), p.020101_1 - 020101_5, 2019/07
Ytterbium dihydride (YbH) shows a well-known transition at 16 GPa from a CaH-type structure to a high-pressure (high-) phase with Yb at hcp sites and unknown H-positions. Here, we report its complete structure determination by neutron diffraction at 34 GPa. Hydrogen(deuterium) is located at 2 and 2 positions of space group , thus forming a high-symmetry "collapsed" close-packed lattice. The transition is sluggish and can be seen as a transfer of 1/2 of the hydrogen atoms from strongly corrugated H-layers to interstitial sites of the Yb-lattice. We demonstrate by first-principles calculations that the transition is related to a change from a completely filled -electron configuration to a fractional -hole (0.25 h) occupation in the high- phase. The charge transfer closes the gap at the transition and leads to a metallic ground state with sizeable electron-phonon interaction involving out-of-plane vibrational modes of interstitial hydrogen.
Hattori, Takanori; Sano, Asami; Machida, Shinichi*; Abe, Jun*; Funakoshi, Kenichi*; Arima, Hiroshi*; Okazaki, Nobuo*
High Pressure Research, 39(3), p.417 - 425, 2019/06
We have developed a technique for neutron diffraction experiments at pressures up to 40 GPa using a Paris-Edinburgh press at the PLANET beamline in J-PARC. To increase the maximum accessible pressure, the diameter of the dimple for sample chamber at the top of the sintered diamond anvils is sequentially reduced from 4.0 mm to 1.0 mm. As a result, the maximum pressure increased and finally reached 40 GPa. By combining this technique with the beam optics which defines the gauge volume, diffraction patterns sufficient for full-structure refinements are obtainable at such pressures.
Yamaguchi, Toshio*; Nishino, Masaaki*; Yoshida, Koji*; Takumi, Masaharu*; Nagata, Kiyofumi*; Hattori, Takanori
European Journal of Inorganic Chemistry, 2019(8), p.1170 - 1177, 2019/02
Neutron diffraction measurements of an aqueous 2 mol dm CaCl solutions in DO have been made at 1 GPa, 298 K as well as 0.1 MPa, 298 K. The experimental structure factors are subjected to Empirical Potential Structure Refinement (EPSR) modeling to reveal the ion hydration and association and solvent water at the atomic level. About seven water molecules surround Ca at the Ca-O and Ca-D distances of 2.44 and 3.70 , respectively, at both pressures, suggesting no significant pressure effect on the cation hydration. On the other hand, the Cl ion shows a drastic change in water oxygen coordination from 7 at 0.1 MPa to 14 at 1 GPa, accompanied by shortening of Cl-O distance from 3.18 to 3.15 . However, the number of water hydrogen atoms around Cl does not change significantly as 6.0 6.7 with shortening Cl-D distance from 2.22 to 2.18 on compression. The pressure effect on the solvent water structure is also drastic as an increase in water oxygen atoms of 4.7 at the O-O distance of 2.79 at 0.1 MPa to 10.3 at 2.85 at 1 GPa. The number of water hydrogen atoms, however, does not change as 1.2 at the O-D distance of 1.74 for both pressures, demonstrating the presence of the OD hydrogen bonds which are significantly bent at 1 GPa at 298 K. This change of hydrogen bonds in water with pressure probably causes the drastic increase in water oxygen atoms around Cl.
Terada, Noriki*; Qureshi, N.*; Chapon, L. C.*; Osakabe, Toyotaka
Nature Communications (Internet), 9, p.4368_1 - 4368_9, 2018/10
Sano, Asami; Hattori, Takanori; Komatsu, Kazuki*; Kagi, Hiroyuki*; Nagai, Takaya*; Molaison, J. J.*; Dos Santos, A. M.*; Tulk, C. A.*
Scientific Reports (Internet), 8(1), p.15520_1 - 15520_9, 2018/10
The pressure response of hydrogen bond in aluminous hydroxide -AlOOH, which is an important candidate for water carrier to the deep Earth in a subducting slab, was investigated using neutron diffraction under high pressure. The symmetrization of hydrogen bond in which hydrogen locates at the center between two oxygen atoms was observed directly for the first time. The present result indicates that the changes of mineral properties such as increase in bulk modulus and sound velocities, which were previously found, were induced by the symmetrization and disorder state that was also found at just below the symmetrization pressure. Even the symmetrization is a small change in the hydrogen location but it is playing an important role in determining the physical properties of minerals.
Soma, Yasutaka; Komatsu, Atsushi; Ueno, Fumiyoshi
Zairyo To Kankyo, 67(9), p.381 - 385, 2018/09
In-situ measurement of electrical conductivity of solution within crevice of SUS316L stainless steel in 288C water has been conducted with newly developed electrochemical sensor system. The sensor measures local electrical conductivity of crevice solution beneath the electrode () with electrochemical impedance method. The sensors were installed at different positions within tapered crevice of SUS316L stainless steel. The crevice specimen with the sensors were immerged into 288C, 8 MPa, pure oxygen saturated high purity water for 100 h. at a position with crevice gap of 59.3m was 8-11S/cm, least deviate from conductivity of 288C pure water (4.4S/cm) and no localized corrosion occurred. On the contrary, at a position with crevice gap of 4.4m increased with time and showed maximum value of 1600S/cm at 70 h. Localized corrosion occurred in the vicinity of this position. Thermodynamic equilibrium calculation showed of 1600S/cm being equivalent to pH of 3 to 3.7. It can be concluded that acidification occurred in tight crevice even under high purity bulk water and resulted in localized corrosion.
Soma, Yasutaka; Ueno, Fumiyoshi
Zairyo To Kankyo, 67(5), p.222 - 228, 2018/05
Localized corrosion in crevice of SUS316 stainless steel after immersion in 288C high purity water with dissolved oxygen concentration of 32 ppm for 100 h was analyzed. Two different types of localized corrosion initiated on grain boundary and inclusions. The former initiated on grain boundary and oxide grown into grain matrix. The oxidized area showed duplex structure composed of microcrystalline FeCrO and island-shaped residual metals. The latter initiated on inclusions containing Ca and S and microcrystalline FeCrO grown into metal matrix. These localized corrosion occurred selectively in oxygen depleted area indicated formation of macroscopic corrosion cell with the corroded area as anode and surrounding oxygenated area as cathode.
Physical Review B, 97(10), p.100101_1 - 100101_4, 2018/03
To verify the first-order liquid-liquid transition (LLT) in liquid Cs reported by Falconi [Phys. Rev. Lett. 125507 (2005)], the pressure dependence of liquid density was measured up to 5 GPa by an X-ray absorption method. The results showed that the density continuously increases over the entire pressure region investigated, without showing the previously reported large volume jump (/17%) at 3.9 GPa. No existence of the volume jump is also suggested from the slopes of the melting curve in the phase diagram. Although the electronic transition is one of the most promising candidates that may cause LLT, it is unlikely to occur in liquid Cs because of the gradual nature of the 6-5 electron transfer.
Hattori, Takanori; Sano, Asami; Machida, Shinichi*; Abe, Jun*; Funakoshi, Kenichi*; Okazaki, Nobuo*
Nippon Kessho Gakkai-Shi, 59(6), p.301 - 308, 2017/12
PLANET is a neutron beamline dedicated to high-pressure experiments. Combining the intense neutron source of J-PARC and high-pressure devices designed for time-of-flight powder neutron diffraction enables precise structure analysis of crystal, liquid and amorphous solids over wide pressure and temperature region of 0-20 GPa and 77-2000K. This beamline is effective for various studies in geophysics, planetary science, physics and chemistry. This paper overviews the beamline and introduces recent results obtained at PLANET.
Iizuka, Riko*; Yagi, Takehiko*; Goto, Hirotada*; Okuchi, Takuo*; Hattori, Takanori; Sano, Asami
Hamon, 27(3), p.104 - 108, 2017/08
Hydrogen is the most abundant element in the solar system and is considered to be one of the promising candidates of the light elements in the Earth's core. However, the amount of hydrogen dissolved in the core and its process are still unknown because hydrogen cannot be detected by X ray and easily escapes from iron at ambient conditions. In this study, we have conducted high-pressure and high-temperature in-situ neutron diffraction experiments on the iron-hydrous mineral system using PLANET in J-PARC. We observed that the water, which was dissociated from a hydrous mineral, reacted with iron to form both iron oxide and iron hydride at about 4 GPa. Iron hydride remained stable after further increase in temperature. This formation occurred at 1000K, where no materials melted. This suggests that hydrogen dissolved into iron before any other light elements dissolved in the very early stage of the Earth's evolution.