CALORIMETRIC STUDIES AND CRYSTAL STRUCTURE OF
[C
2
H
10
N
2
]
5
(Sb
2
Br
11
)
2
4H
2
O
S. Chaabouni
1
*, S. Kamoun
1
, and J. Jaud
2
1
Laboratoire de Cristallochimie du Solide, Ecole Nationale d’Inge ´nieurs de Sfax,
3038, Sfax, Tunisia
2
Centre d’Elaboration de Mate ´riaux et d’Etudes Structurales, CNRS, BP 4347,
31055 Toulouse Cedex, France
(Refereed)
Received June 11, 1997; Accepted June 18, 1997
ABSTRACT
The chemical preparation and the main crystallographic, calorimetric, and struc-
tural features are given for a new alkyldiammonium antimony halogenide.
[NH
3
(CH
2
)
2
NH
3
]
5
(Sb
2
Br
11
)
2
4H
2
O salt is monoclinic P2
1
/a with unit-cell dimen-
sions a = 14.346(2), b = 13.206(1), c = 17.027(2) Å, = 113.05(1)°, Z = 2;
D
m
= 2.985 M g
-3
;D
x
= 2.941 M g
-3
; = 127.3 cm
-1
; F(000) = 2388; T =
298 K; R = 0.052 and R
w
= 0.057 for 4136 observed reflections. The exami-
nation of the structure shows a layer arrangement parallel to the b axis: planes of
(Sb
2
Br
11
)
5-
bioctahedra alternate with planes of [(CH
2
)
2
(NH
3
)
2
]
2+
. The
(Sb
2
Br
11
)
5-
bioctahedra are connected through O(W)–H…Br hydrogen bonds, so
that infinite chains of the composition [Sb
2
Br
11
(H
2
O)]
n
5n-
are formed in the
structure parallel to the b axis. The structure of this compound is built from
(Sb
2
Br
11
)
5-
anions, [(CH
2
)
2
(NH
3
)
2
]
2+
cations, and zeolitic water molecules con-
nected by hydrogen bonds. The thermogravimetric analysis and differential scan-
ning calorimetric studies show that the dehydration of this salt occurs in two steps:
at 377 and 391 K, respectively, with a loss of two water molecules per step. The
anhydrous salt starts to decompose at 490 K. © 1998 Elsevier Science Ltd
KEYWORDS: C. differential scanning calorimetry, C. thermogravimetric
analysis, D. crystal structure
*To whom correspondence should be addressed.
Materials Research Bulletin, Vol. 33, No. 3, pp. 377–388, 1998
Copyright © 1998 Elsevier Science Ltd
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