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6. Comparison of the thermal behavior of BaCsP3O9.2H2O with

The thermal behavior of BaNH4P3O9.2H2O and BaTlP3O9.2H2O [16] was studied (Laboratory of Physical Chemistry of Materials, Ben M'sik faculty of Sciences, Casablanca, Morocco). It would be useful to compare the thermal behavior of BaCsP3O9.2H2O with that of its isotypic

The thermal behavior of BaCsP3O9.2H2O is different from that obtained in the case of BaTlP3O9.2H2O [16], which leads to the anhydrous barium and thallium BaTlP3O9 cyclotriphosphate at 280�C. After amorphous X-ray state, BaTlP3O9 remains stable till its melting

BaTlP3O9:2H2<sup>O</sup> ! <sup>70</sup>�270�<sup>C</sup> Amorphous X � ray <sup>P</sup>hase <sup>þ</sup> <sup>2</sup>H2<sup>O</sup> ! <sup>300</sup>�<sup>C</sup> BaTlP3O<sup>9</sup>

The total dehydration of BaCsP3O9.2H2O, after passing through an amorphous X-ray state,

BaCsP3O9:2H2<sup>O</sup> ! <sup>100</sup>�250�<sup>C</sup> Amorphous X � ray Phase <sup>þ</sup> <sup>2</sup>H2<sup>O</sup> ! <sup>450</sup>�<sup>C</sup> <sup>¼</sup> BaCs4ð Þ PO<sup>3</sup> <sup>6</sup> crystallized

The cyclotriphosphate BaCsP3O9.2H2O was obtained as a monocrystal by the resin exchange method. It crystallizes in the monoclinic system, space group P21/n, Z = 4, and is an isotype of

The crystal structure of BaCsP3O9.2H2O was solved from 2448 independent reflections. The final value of the unweighted reliability factor is R = 0.0329. The unit cell of BaCsP3O9.2H2O

(1)O4, P(2)O4, and P(3)O4 tetrahedra. The three tetrahedra have no special characteristics. The P3O9 cycle observed in the structure of BaCsP3O9.2H2O has no internal symmetry. The cohe-

geometrical characteristics of the three P(1)O4, P(2)O4, and P(3)O4 tetrahedra of the P3O9 cycle

The thermogram (TG) of BaCsP3O9.2H2O shows that dehydration takes place in two distinct

The total removal of the water at 560�C is accompanied by a total destruction of the BaCsP3O9.2H2O structure, probably leading to a mixture of amorphous oxidesin X-ray diffraction BaO + 3/2 P2O5 + ½ Cs2O. The product resulting from calcinations of BaCsP3O9.2H2O

are quite similar to those observed generally in cyclotriphosphates.

between 300 and 560�C is the long chain polyphosphate BaCs4(PO3)6.

<sup>3</sup>� rings, each of them consists of three crystallographically independent P

<sup>3</sup>� is ensured via the associated cations Cs<sup>+</sup> and Ba2+. The main

<sup>∞</sup>ð Þ BaP2O6amorphous in X � ray diffraction :

leads to monobarium polyphosphate and tetracerium BaCs4(PO3)6 at 500�C [17, 18].

BaNH4P3O9.2H2O and BaTlP3O9.2H2O

compounds BaNH4P3O9.2H2O and BaTlP3O9.2H2O.

þ ¾ Ba PO ð Þ<sup>3</sup> <sup>2</sup>

BaNH4P3O9.2H2O and BaTlP3O9.2H2O.

point at 670�C.

108 Chalcogen Chemistry

7. Conclusion

contains four P3O9

sion between the cycles P3O9

steps between 70 and 560�C.

Soufiane Zerraf<sup>1</sup> \*, Mustafa Belhabra<sup>1</sup> , Aziz Kheireddine<sup>1</sup> , Malika Tridane1,2, Hicham Moutaabbid<sup>3</sup> , Mohammed Moutaabbid<sup>1</sup> and Said Belaaouad<sup>1</sup>

\*Address all correspondence to: soufiane.zerraf@gmail.com

1 Laboratory of Physical Chemistry of Materials, Ben M'sik Faculty of Sciences, Casablanca, Morocco

2 Regional Center for Education and Training Occupations Casablanca Anfa, Bd Bir Anzarane Casablanca, Morocco

3 Institute of Mineralogy, Physics of Materials, and Cosmochemistry (IMPMC) Sorbonne Universities—UPMC University Paris, Cedex, France
