A group of new compounds belonging to hauyne type structure could be synthesized by means of substitution of the components of hauyne, Ca
2Na
6Al
6Si
6O
24(SO
4)
2, i.e. all of Ca and Na by Ca, Sr or Cd, Al by Be, and all of Al and Si by Al, moreover SO
4 by CrO
4, MoO
4 or WO
4.
As the representatives of these compounds, Ca
8Al
12O
24(SO
4)
2, Ca
8Al
12O
24(WO
4)
2, Sr
8Al
12O
24(SO
4)
2 and Sr
8Al
12O
24(WO
4)
2 were chosen and the crystal structure was examined in comparison with hauyne, in which the space group was selected as I 23.
The values of reliability
R=∑||
F0|-|
Fc||/∑|
F0| for each compound were all obtained as below as 0.20, if a set of suitable parameteres was given for the atoms in each compound.
It was confirmed that these compounds crystallized as hauyne type structure, therefore AlO
4 tetrahedra linked each other, irrespective of the absence of SiO
4, to form 3-dimensional framework. The strain of each tetrahedron of SiO
4 or AlO
4 in hauyne and calcium containing compounds was found as that the 2 edges were longer than 4 edges, contrary to the result obtained by Machatschki on hauyne. In the case of strontium containing compounds, however, the 2 edges were shorter than the 4 edges.
In relation to the fact that these aluminate double salts possessed hydraulic property, the existence of 4-fold coordinated Al, asymmetrically coordinated cation such as Ca, and isolated complex anion such as SO
4 in the structure was characteristic.
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