Gismondine from Montalto di Castro, Italy [Ca3.91AIT.77Sis.22032.17.57 H20], a = 10.0199(4), b = 10.6373(5), c = 9.8316(5) A, [3 = 92.561 (6) °, space group P211c, dehydrated in vacuum for 1 and 24 h and transformed into two new phases, here called gismondine (1 h) and gismondine (24 h), respectively. Gismondine (1 h) is characterized by 9.5% water loss and by a small decrease in the cell volume (AV = 0.6%); cell parameters are a = 9.989(3), b = 10.616(3), c = 9.820(3)/~, and [3 = 92.57(2) °. The framework is almost undistorted, but a rearrangement of water molecules causes a change in space group to P21, with formation of a more regular 6-coordinated Ca polyhedron. The final Rw value (isotropic displacement factors) is 7.6%. Gismondine (24 h) is characterized by the orthorhombic space group P2~2121 and a unit cell doubled with respect to the nondehydrated sample; cell parameters are a = 13.902(9), b = 8.892(4), and c = 13.952(5) ,~. More than 50% of water is lost, the framework is highly distorted, and the channels are strongly squashed. Residual water sites are fully occupied. Ca polyhedra are seven-fold coordinated and are linked by vertices to form infinite chains. The final Rw value (isotropic displacement factors) is 7.6%.

Structural modifications induced by dehydration in the zeolite gismondine.

QUARTIERI, Simona;
1993-01-01

Abstract

Gismondine from Montalto di Castro, Italy [Ca3.91AIT.77Sis.22032.17.57 H20], a = 10.0199(4), b = 10.6373(5), c = 9.8316(5) A, [3 = 92.561 (6) °, space group P211c, dehydrated in vacuum for 1 and 24 h and transformed into two new phases, here called gismondine (1 h) and gismondine (24 h), respectively. Gismondine (1 h) is characterized by 9.5% water loss and by a small decrease in the cell volume (AV = 0.6%); cell parameters are a = 9.989(3), b = 10.616(3), c = 9.820(3)/~, and [3 = 92.57(2) °. The framework is almost undistorted, but a rearrangement of water molecules causes a change in space group to P21, with formation of a more regular 6-coordinated Ca polyhedron. The final Rw value (isotropic displacement factors) is 7.6%. Gismondine (24 h) is characterized by the orthorhombic space group P2~2121 and a unit cell doubled with respect to the nondehydrated sample; cell parameters are a = 13.902(9), b = 8.892(4), and c = 13.952(5) ,~. More than 50% of water is lost, the framework is highly distorted, and the channels are strongly squashed. Residual water sites are fully occupied. Ca polyhedra are seven-fold coordinated and are linked by vertices to form infinite chains. The final Rw value (isotropic displacement factors) is 7.6%.
1993
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/2012022
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 44
  • ???jsp.display-item.citation.isi??? 45
social impact