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Synthesis and crystal structure determination of hydrated potassium dawsonite from powder diffraction data

Lucia Fernandez-Carrasco and Jordi Rius
Synthesis and crystal structure determination of hydrated potassium dawsonite from powder diffraction data
European Journal of Mineralogy (February 2006) 18 (1): 99-104

Abstract

A new hydrated phase, closely related to a compound recently shown to be involved in the alkaline hydrolysis of cacium aluminate cement (CAC), appeared at below 25 degrees C and was detected by XRD. This new phase was synthesized in a pure form and its crystal structure determined from powder XRD. It has a 8.3312, b 11.2670, c 5.661 Aa, space group Pna2 (sub 1) , Z = 4, the chemical formula being KAl(CO (sub 3) )(OH) (sub 2) . H (sub 2) O. The unit cell contains two carboaluminate chains formed from the basic unit [Al (sub 2) (OH) (sub 4) (CO (sub 3) ) (sub 2) ] (super 2- ) propagating along the c axis and being stabilized by a complex H-bond network. The arrangement of these chains is similar to that found in dawsonite, so that the atomic positions of K (super +) and Na (super +) in both structures are also similar. Hydrated potassium dawsonite slowly transforms into the non-hydrated form at room temperature. Due to the most favourable formation conditions, i.e., lower temperature and higher humidity, this hydrated phase could eventually be found in AC pastes or mortars.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 18
Serial Issue: 1
Title: Synthesis and crystal structure determination of hydrated potassium dawsonite from powder diffraction data
Affiliation: CSIC, Institut de Ciencia de Materials, Barcelona, Spain
Pages: 99-104
Published: 200602
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 15
Accession Number: 2006-036664
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 5 tables
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 200620
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