GEOSCAN Search Results: Fastlink


TitleCrystal structure of the mineral strontiodresserite from laboratory powder diffraction data
AuthorWhitfield, P S; Mitchell, L D; Le Page, Y; Margeson, J; Roberts, A CORCID logo
SourcePowder Diffraction vol. 25, no. 4, 2010 p. 322-328, Open Access logo Open Access
Alt SeriesEarth Sciences Sector, Contribution Series 20100371
PublisherCambridge University Press (CUP)
Mediapaper; on-line; digital
File formatpdf
AreaMontreal Island; Saint-Michel
Lat/Long WENS-74.0000 -73.5000 45.7500 45.5000
Subjectsmineralogy; crystallography; x-ray diffraction; powder diffraction; electron microscopy; morphology, crystal; strontiodresserite; calcium; strontium; aluminum; carbonates; mineral occurrences; optical properties; chemical analysis; thermal analyses; mineral associations; Francon Quarry
Illustrationstables; spectra; photomicrographs
Released2012 02 29
AbstractThe crystal structure of the mineral strontiodresserite, (Sr,Ca)Al2(CO3)2(OH)4·H2O, from the Francon Quarry, Montreal, Quebec, Canada, has been solved from laboratory powder diffraction data using a combination of charge-flipping and simulated annealing methods. The structure is orthorhombic in space group Pnma with a = 16.0990(7), b = 5.6133(3) and c = 9.1804(4) Å (Z = 4) and the framework of the mineral is isostructural with that of dundasite. The strontium has a coordination number of 9 and the carbonate anions form a bridge between the SrO9 polyhedra and AlO6 octahedra. The water molecule lies in a channel that runs parallel to the b-axis. An ordered network of hydrogen atoms could be uniquely determined from crystal-chemical principles in the channels of strontiodresserite. Ab initio DFT energy minimization of the whole structure gave results in full agreement with X-ray refinement results for non-hydrogen atoms. The stability of this model (as well as that of the corresponding model of dundasite) in the proposed Pnma space group was tested by DFT optimization in space group P1 of random small distortions of this structure. This test confirms that both minerals are isostructural, including their hydrogen-bond networks.

Date modified: