|
|
|
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Dipartimento di Scienze della Terra, Largo S. Eufemia, 19, I-41100 Modena, Italy
2 Dipartimento di Scienze della Terra, Salita Sperone 31, I-98166 Messina-S.Agata, Italy
3 Dipartimento di Scienze Chimiche, Fisiche e Matematiche, Università dellInsubria, via Lucini 3, I-22100, Como, Italy
Correspondence: * E-mail: simonaq{at}unimo.it
Pressure-induced structural modifications in the zeolite bikitaite are studied by means of in situ synchrotron X-ray powder diffraction and ab initio molecular dynamics. The experimental cell parameters were refined up to 9 GPa, at which pressure we found reductions of 4.5, 4.5, 6.3, and 15% in a, b, c, and V, respectively. Minor variations were observed for the cell angles. Complete X-ray amorphization is not achieved in the investigated P range, moreover the P-induced effects on the bikitaite structure are completely reversible. Because it was possible to extract only the cell parameters from the powder patterns, the atomic coordinates at 5.7 and 9.0 GPa were obtained by means of Car-Parrinello simulations using the unit-cell parameters experimentally determined at these pressures. Analysis of the computational results for increasing pressures showed that the volume contraction is essentially due to rotations of the tetrahedra; the 8-ring channels become more circular; the pyroxene chain becomes more corrugated in the b-c plane; and the mean Li-O bond distances and coordination polyhedral volumes decrease with increasing pressure without significant distortion of the internal angles. The peculiar aspect of the bikitaite structure, i.e., the presence in the channels of a "floating" one-dimensional water chain, is only partially maintained at high pressure; the compression brings framework O atoms close enough to water hydrogen atoms to allow the formation of host-guest hydrogen bonds, without, however, destroying the one-dimensional chain.
This article has been cited by other articles:
![]() |
S. Ori, S. Quartieri, G. Vezzalini, and V. Dmitriev Pressure-induced structural deformation and elastic behavior of wairakite American Mineralogist, January 1, 2008; 93(1): 53 - 62. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Xu, J. Zhang, Y. Zhao, G. D. Guthrie, D. D. Hickmott, and A. Navrotsky Compressibility and pressure-induced amorphization of guest-free melanophlogite: An in-situ synchrotron X-ray diffraction study American Mineralogist, January 1, 2007; 92(1): 166 - 173. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. D. GATTA A comparative study of fibrous zeolites under pressure European Journal of Mineralogy, June 1, 2005; 17(3): 411 - 421. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. V. GORYAINOV Amorphization of natrolite and edingtonite at high pressure European Journal of Mineralogy, April 1, 2005; 17(2): 201 - 206. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Fois, A. Gamba, G. Tabacchi, R. Arletti, S. Quartieri, and G. Vezzalini The "template" effect of the extra-framework content on zeolite compression: The case of yugawaralite American Mineralogist, January 1, 2005; 90(1): 28 - 35. [Abstract] [Full Text] [PDF] |
||||
![]() |
O. Ferro, O. Ferro, S. Quartieri, G. Vezzalini, C. Ceriani, E. Fois, A. Gamba, and G. Cruciani Dehydration dynamics of bikitaite: Part I. In situ synchrotron powder X-ray diffraction study American Mineralogist, January 1, 2004; 89(1): 94 - 101. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Ceriani, C. Ceriani, E. Fois, A. Gamba, G. Tabacchi, O. Ferro, S. Quartieri, and G. Vezzalini Dehydration dynamics of bikitaite: Part II. Ab initio molecular dynamics study American Mineralogist, January 1, 2004; 89(1): 102 - 109. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Arletti, R. Arletti, O. Ferro, S. Quartieri, A. Sani, G. Tabacchi, and G. Vezzalini Structural deformation mechanisms of zeolites under pressure American Mineralogist, October 1, 2003; 88(10): 1416 - 1422. [Abstract] [Full Text] [PDF] |
||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |