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High-pressure synchrotron X-ray diffraction study of tremolite and actinolite in various fluids
공미혜,Thomas Vogt,이용재 한국물리학회 2018 Current Applied Physics Vol.18 No.11
Pressure-dependent structural and morphological changes of two amphibole minerals, tremolite and actinolite, were investigated up to 7.0 GPa using synchrotron X-ray powder diffraction underthree different pressure transmission media (PTM): water (W), CO2 and silicone oil (SI). The elastic response of tremolite and actinolite are found to be dependent on the PTM used. When using water (W) as PTM, tremolite and actinolite show normal volume contractions with bulk moduli of 74(1) and 78(1) GPa, respectively. When using CO2 as PTM, we observe the formation of calcite from tremolite above 3.8(1) GPa, whereas actinolite did not show any carbonation reaction. Under silicone oil PTM, we observe modulated volume contraction behaviors in both samples, compared to water and CO2 PTM, with bulk moduli in the order of 90(1) and 94(4) GPa for tremolite and actinolite, respectively.
Natrolites with different Fe<sup>2+/</sup>Fe<sup>3+</sup> cation ratios
Lee, Yongmoon,Vogt, Thomas,Lee, Yongjae Elsevier 2017 Microporous and mesoporous materials Vol.244 No.-
<P><B>Abstract</B></P> <P>We report the synthesis and structural characterization of two iron-exchanged natrolites, Fe<SUP>2+</SUP> <SUB>4.0</SUB>Fe<SUP>3+</SUP> <SUB>2.7</SUB>Al<SUB>16</SUB>Si<SUB>24</SUB>O<SUB>80</SUB>·29(1)H<SUB>2</SUB>O (Fe-NAT4951) and Fe<SUP>2+</SUP> <SUB>6.4</SUB>Fe<SUP>3+</SUP> <SUB>1.1</SUB>Al<SUB>16</SUB>Si<SUB>24</SUB>O<SUB>80</SUB>·24H<SUB>2</SUB>O (Fe-NAT8119) at different pressures and temperatures using ambient, high-temperature and in-situ high-pressure synchrotron powder X-ray diffraction, Mössbauer spectroscopy and extended X-ray absorption fine structure (EXAFS). At ambient conditions, Fe-NAT4951 crystallizes in an orthorhombic structure with space group <B>F</B> <I>dd2</I> whereas the structure of Fe-NAT8119 is monoclinic with <B>C</B> <I>c</I> symmetry. Due to the presence of more H<SUB>2</SUB>O molecules in Fe-NAT4951 the channels are more circular as indicated by a T<SUB>5</SUB>O<SUB>10</SUB> (T = Si,Al) chain rotation angle of 12.6(1)° compared to 20.4(1)° in Fe-NAT8119. The coordination number of the Fe<SUP>2+</SUP> and Fe<SUP>3+</SUP> cations in the channels of Fe-NAT4951 is 3 and 4, whereas Fe-NAT8119 has 7- and 4-fold coordination, respectively. The two materials behave differently under hydrostatic pressures: due to a discontinuous pressure-induced hydration the volume of Fe-NAT8119 expands by 14.1(1) % near 1.0(1) GPa, whereas the volume of Fe-NAT4951 gradually decreases with pressure. Under increasing temperature and as a result of abrupt dehydration, the unit cell volume of Fe-NAT4951 contracts by ca. 8.3(1) % near 125(1) °C whereas Fe-NAT8119 contracts only by ca. 5.0(1) % near 225(5) °C.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Comparative structural study of Fe-NATs at (non-) ambient conditions. </LI> <LI> Mössbauer spectroscopy, Rietveld refinement and EXAFS were examined to characterize Fe-NATs. </LI> <LI> Structural evolutions of Fe-NATs at (non-) ambient conditions were related to distributions of Fe2+ and Fe3+. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kim, Yonghwi,Choi, Jinhyuk,Vogt, Thomas,Lee, Yongjae Mineralogical Society of America 2018 The American mineralogist Vol.103 No.1
<P><B>Abstract</B></P><P>In situ high-pressure single-crystal X-ray diffraction studies of mesolite, an aluminosilicate composed of stacks of Na<SUP>+</SUP>-containing natrolite and Ca<SUP>2+</SUP>-containing scolecite layers in the ratio of 1:2, showed two discrete steps of pressure-induced hydration (PIH): first H<SUB>2</SUB>O molecules are inserted into the natrolite layers between ∼0.5 and ∼1.5 GPa and subsequently into the scolecite layers. During the PIH in the natrolite layers, the coordination environment of Na<SUP>+</SUP>changes from six to seven, the same as that of Ca<SUP>2+</SUP>in the scolecite layers. While the natrolite layers behave as in the mineral natrolite, the scolecite layers show a different behavior from the mineral scolecite by adopting the super-hydrated natrolite-type structure at higher pressure, as a larger distortion is not favorable in the 1:2 layered framework. This spatial separation of inserted H<SUB>2</SUB>O during PIH and the growing structural similarity of the two layers result in a weakening of<I>k</I>≠ 3<I>n</I>reflections maintaining the 1:2 layer configuration. Our study of this unique behavior of mesolite provides a simple model of structuration under pressure, and the implications of our experimental findings are discussed.</P>
Seoung, Donghoon,Lee, Yongmoon,Kao, Chi-Chang,Vogt, Thomas,Lee, Yongjae American Chemical Society 2015 Chemistry of materials Vol.27 No.11
<P>In situ high pressure X-ray powder diffraction studies of natrolite (NAT) containing the divalent extra-framework cations (EFC) Sr<SUP>2+</SUP>, Ca<SUP>2+</SUP>, Pb<SUP>2+</SUP>, and Cd<SUP>2+</SUP> reveal that they can be superhydrated in the presence of water. In the case of Ca-NAT, Sr-NAT, and Pb-NAT pressure-induced hydration (PIH) inserts 40 H<SUB>2</SUB>O/unit cell into the zeolite compared to 32 in superhydrated natrolites containing monovalent EFC. Cd-NAT is superhydrated in one step to a zeolite containing 32 H<SUB>2</SUB>O/unit cell. PIH of Ca-NAT and Sr-NAT occurs in two steps. During PIH of Pb-NAT three distinct steps have been observed. The excess H<SUB>2</SUB>O in natrolites with divalent EFC are accommodated on sites no longer required for charge compensation. Two distinct families with ordered and disordered EFC–water topologies have been found. Our work established the importance of both size and charge of the EFC in PIH.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2015/cmatex.2015.27.issue-11/acs.chemmater.5b00506/production/images/medium/cm-2015-00506p_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm5b00506'>ACS Electronic Supporting Info</A></P>
Im, Junhyuck,Yim, Narae,Kim, Jaheon,Vogt, Thomas,Lee, Yongjae American Chemical Society 2016 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.138 No.36
<P>Pressure-dependent structural and chemical changes of the zeolitic imidazolate framework compound ZIF-8 have been investigated using different pressure transmitting media (PTM) up to 4 GPa. The unit cell of ZIF-8 expands and contracts under hydrostatic pressure depending on the solvent molecules used as PTM. When pressurized in water up to 2.2(1) GPa, the unit cell of ZIF-8 reveals a gradual contraction. In contrast, when alcohols are used as PTM, the ZIF-8 unit cell volume initially expands by 1.2% up to 0.3(1) GPa in methanol, and by 1.7% up to 0.6(1) GPa in ethanol. Further pressure increase then leads to a discontinuous second volume expansion by 1.9% at 1.4(1) GPa in methanol and by 0.3% at 2.3(1) GPa in ethanol. The continuous uptake of molecules under pressure, modeled by the residual electron density derived from Rietveld refinements of Xray powder diffraction, reveals a saturation pressure near 2 GPa. In non-penetrating PTM (silicone oil), ZIF-8 becomes amorphous at 0.9(1) GPa. The structural changes observed in the ZIF-8-PTM system under pressure point to distinct molecular interactions within the pores.</P>
Im, Junhyuck,Lee, Yongmoon,Blom, Douglas A.,Vogt, Thomas,Lee, Yongjae Royal Society of Chemistry 2016 Dalton Transactions Vol.45 No.4
<P>We report on high-pressure and high-temperature chemical transformations of Pb2+-exchanged natrolite (Pb-NAT, Pb8Al16Si24O80.16H(2)O) using a combination of in situ synchrotron X-ray powder diffraction and ex situ HAADF-STEM real space imaging. Three high-pressure polymorphs of natrolites (Pb-NAT-I, II, III) are observed via step-wise pressure-induced hydrations (PIH) up to 4.5 GPa, during which the number of H2O molecules located inside the natrolite channel increases from 16 to 40 H2O per unit-cell. At 4.5 GPa after heating the high-pressure Pb-NAT-III phase at 200 degrees C a reconstructive phase transits into a lawsonite phase (Pb-LAW, Pb4Al8Si8O28(OH)8.4H(2)O) with an orthorhombic space group Pbnm and a = 5.8216(9), b = 9.114(1) and c = 13.320(1) angstrom is obseed. The structure of the recovered Pb-LAW phase was characterized using Rietveld refinement of the in situ synchrotron X-ray powder diffraction data and HAADF-STEM real space imaging. In the recovered Pb-LAW phase the Pb2+ content is close to 42 wt% and as bond valence approximations reveal the Pb2+ cations are more tightly coordinated to the framework oxygen atoms than originally in the natrolite phase.</P>