CHARACTERIZATION AND CRYSTAL STRUCTURE OF A NEW LAYERED CADMIUM DIPHOSPHATE: KCdHP2O7x2H2O
S. Kouass1, A. Selmi2,3, H. Chebbi4,5, A. Guesmi5,6
1Institut National de Recherche et d'Analyse Physico-chimique Sidi-Thabet, 2020 Tunis, Tunisia
2Universite de Gafsa, Sidi Ahmed Zarroug, 2112 Gafsa, Tunisia
3Universite de Carthage, 7021 Zarzouna, Bizerte, Tunisia
4Universite de Tunis, Rue Jawaher Lel Nehru, 1089 Montfleury, Tunis, Tunisia
chebhamouda@yahoo.fr
5Universite de Tunis El Manar, El Manar II, 2092 Tunis, Tunisia
6Al-Baha University, Al Mukhwah, Al Baha Region, Kingdom of Saudi Arabia
Ключевые слова: crystal structure, cadmium diphosphate, bond-valence-sum, FT-IR, Raman
Страницы: 717-721
Аннотация
A new potassium cadmium hydrogen diphosphate dihydrate, KCdHP2O7×2H2O (1), has been synthesized by slow evaporation at room temperature and characterized by FT-IR, Raman, TG-DTA, and single crystal X-ray diffraction. Compound (1) crystallizes in the orthorhombic Pcmn space group with the unit cell parameters a = 6.5814(8) Å, b = 7.9428(9) Å, c = 15.961(6) Å, V = 834.4(3) Å3 and Z = 4. Its structure consists of polyhedral layers parallel to the ab plane where each CdO6 octahedron ( m position) shares four edges with three different diphosphate groups. In the Cd octahedron, two oxygen atoms residing in ( m ) special positions belong to coordinated water molecules. These layers are joint by K+ cations (4 c Wyckoff position) and hydrogen bonds, leading thus to a two-dimensional framework. The structural model is supported by the bond-valence-sum validation tool as calculated valences are close to the formal oxidation numbers.
DOI: 10.15372/JSC20160407 |
