TY - JOUR
T1 - Anisotropic compression of edingtonite and thomsonite to 6GPa at room temperature
AU - Hriljac, Joseph
AU - Lee, Y
AU - Vogt, T
AU - Studer, A
PY - 2004/2/1
Y1 - 2004/2/1
N2 - Polycrystalline samples of natural edingtonite (New Brunswick, Canada) and thomsonite (Oregon, USA) were studied up to 6 GPa using monochromatic synchrotron X-ray powder diffraction and a diamond-anvil cell with a methanol:ethanol:water mixture as a penetrating pressure-transmitting fluid. Unlike natrolite, previously studied under the same conditions, edingtonite and thomsonite do not show any apparent pressure-induced hydration (PIH) or phase transitions. All these fibrous zeolites are characterized by their anisotropic compressibilities, with the linear compressibilities of the fibrous chains (c-axis) being as small as one third of those perpendicular to the chains (a-, b-axes); for edingtonite, beta(0)(a)=0.0050(3) GPa(-1), beta(0)(b)=0.0054(2) GPa(-1), beta(0)(c)=0.0034(1) GPa(-1); for thomsonite, beta(0)(a)= 0.0080(2) GPa(-1), beta(0)(b)=0.0084(2) GPa(-1), beta(0)(c)=0.0032(1) GPa(-1). The pressure-volume data were fitted to a second-order Birch-Murnaghan equation of state using a fixed pressure derivative of 4. As a result of the 0000-type connectivity of the chains, the bulk modulus of edingtonite is found to be about 40% larger than that of thomsonite; K-0(EDI)=73(3) GPa, K-0(THO)=52(1) GPa. Distance least-squares refinements were used to model the expected framework, following the observed linear compression behaviors. The chain-bridging T-O-T angle is proposed to be correlated with the different compressibilities across the chains in each framework type.
AB - Polycrystalline samples of natural edingtonite (New Brunswick, Canada) and thomsonite (Oregon, USA) were studied up to 6 GPa using monochromatic synchrotron X-ray powder diffraction and a diamond-anvil cell with a methanol:ethanol:water mixture as a penetrating pressure-transmitting fluid. Unlike natrolite, previously studied under the same conditions, edingtonite and thomsonite do not show any apparent pressure-induced hydration (PIH) or phase transitions. All these fibrous zeolites are characterized by their anisotropic compressibilities, with the linear compressibilities of the fibrous chains (c-axis) being as small as one third of those perpendicular to the chains (a-, b-axes); for edingtonite, beta(0)(a)=0.0050(3) GPa(-1), beta(0)(b)=0.0054(2) GPa(-1), beta(0)(c)=0.0034(1) GPa(-1); for thomsonite, beta(0)(a)= 0.0080(2) GPa(-1), beta(0)(b)=0.0084(2) GPa(-1), beta(0)(c)=0.0032(1) GPa(-1). The pressure-volume data were fitted to a second-order Birch-Murnaghan equation of state using a fixed pressure derivative of 4. As a result of the 0000-type connectivity of the chains, the bulk modulus of edingtonite is found to be about 40% larger than that of thomsonite; K-0(EDI)=73(3) GPa, K-0(THO)=52(1) GPa. Distance least-squares refinements were used to model the expected framework, following the observed linear compression behaviors. The chain-bridging T-O-T angle is proposed to be correlated with the different compressibilities across the chains in each framework type.
KW - thomsonite
KW - distance least-squares
KW - anisotropic compression
KW - edingtonite
KW - bulk modulus
KW - high pressure
UR - http://www.scopus.com/inward/record.url?scp=1542320657&partnerID=8YFLogxK
U2 - 10.1007/s00269-003-0330-6
DO - 10.1007/s00269-003-0330-6
M3 - Article
SN - 1432-2021
SN - 1432-2021
VL - 31
SP - 22
EP - 27
JO - Physics and Chemistry of Minerals
JF - Physics and Chemistry of Minerals
ER -