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Structural studies on Ca 3 Al 4 MgO 10 (C 3 A 2 M)—A ternary phase in the system CaO–Al 2 O 3 –MgO
Author(s) -
Kahlenberg Volker,
Albrecht Richard,
Schmidmair Daniela,
Krüger Hannes,
Krüger Biljana,
Tribus Martina,
Pauluhn Anuschka
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16001
Subject(s) - orthorhombic crystal system , crystallography , crystal structure , ternary operation , phase (matter) , powder diffraction , materials science , phase diagram , diffraction , chemistry , physics , organic chemistry , computer science , optics , programming language
In a sequence of temperature‐dependent solid‐state reactions in the system CaO–Al 2 O 3 –MgO the formation of the ternary phase Ca 3 Al 4 MgO 10 or C 3 A 2 M has been studied. Whereas the compound could not be prepared at 1200°C, a yield of 85 wt.‐% of Ca 3 Al 4 MgO 10 was obtained at 1320°C (incongruent melting point: 1330°C). Powder diffraction data compare well with results of previous investigations from the 1960s. Single crystals of Ca 3 Al 4 MgO 10 could be retrieved from the sinter‐pellets. Basic crystallographic data are as follows: orthorhombic symmetry, space group Pbcm , a = 5.14073(8), b = 16.7576(2), c = 10.70977(16) Å, V = 922.61(2) Å 3 , Z = 4. Using synchrotron diffraction data it was possible to solve the crystal structure. Least‐squares refinements resulted in a residual of R(|F|) = 0.021 for 1000 independent observed reflections with I > 2σ(I) and 97 parameters. The structure contains [ TO 4 ]‐tetrahedra (T=Al,Mg) forming a three‐dimensional (3‐D) framework whose topological characteristics have been determined. Al‐Mg distributions on the different T‐sites have been studied. The calcium cations are located in voids of the network. More than 50 years after its first observation our investigation clarifies the crystal structure of a compound belonging to a system that is of relevance for several fields of materials science.