Skip to main content

A New Investigation of the Cl–CO3 2− Substitution in AFm Phases

Buy Article:

$51.00 plus tax (Refund Policy)


Chloride to carbonate substitution in AFm phase of general formulae [Ca2Al(OH)6]·[Cl1−x ·(CO3) x/2·(2+x/2)H2O] (or 3CaO·Al2O3·(CaCl2)1−x ·(CaCO3) x ·(10+x)H2O written in cement notation) has been characterized by studying 12 powdered samples synthesized at 25° and at 85°C. The existence of a solid solution has been highlighted. It forms one stable rhombohedral [Ca2Al(OH)6]·[Cl1−x ·(CO3) x/2·(2+x/2)H2O] solid solution with 0.25≤x≤0.95, isotypic with the recently described chloro-carboaluminate of [Ca2Al(OH)6]·[Cl0.5·(CO3)0.25· 2.25H2O] composition. A second metastable monoclinic [Ca2Al(OH)6]·[Cl1−x ·(CO3) x/2·(2+x/2)H2O] solid solution has also been identified in a less extended x domain. The structural relationship between these two stable and metastable chloro-carboaluminate polymorphs shows similarities with the structural transition of the Friedel's salt (from rhombohedral high-temperature-structure to monoclinic low-temperature-structure at about 35°C). The two [Ca2Al(OH)6]· [Cl1−x ·(CO3) x/2·(2+x/2)H2O] solid solutions are simultaneously present, in quite equivalent weight amounts, in samples synthesized at room temperature, whereas only the stable rhombohedral polymorph is observed for samples synthesized at 85°C. Raman spectroscopy has been successfully used to locate carbonate in the structure. The [CO3] symmetric stretching mode is observed at 1068 cm−1 for monocarboaluminate (x=1) for carbonate directly bonded to main layer, while it is observed at 1086 cm−1 for both chloro-carboaluminate polymorphs, which is characteristic of interlayer carbonate.

Document Type: Research Article


Affiliations: 1: Commissariat à l'Energie Atomique et aux énergies alternatives, CEA DEN/DTCD/SPDE, F-30207 Bagnols sur Cèze, France 2: Institut de Chimie Séparative de Marcoule, UMR 5257 CEA/CNRS/UM2/ENSCM, F-30207 Bagnols-sur-Cèze, France

Publication date: June 1, 2011


Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more