CRYSTAL STRUCTURE OF THE MIXED COMPOUND K_2.54(NH₄)_1.46Hg₃Cl₁₀.2H₂O

A. Kabadou, R. Ben Hassen and A. Ben Salah

Laboratoire de L'Etat solide, Faculté des sciences de Sfax-3038 TUNISIE

The present work intends to study the solid state phase diagram with the border compounds NH₄HgCl₃ and K₂HgCl₄.H₂0.

Single crystals of K_2.54(NH₄)_1.46Hg₃Cl₁₀·2H₂O were grown by slow evaporation from a mixture of water and acetone containing stoichiometric KCl- NH₄Cl-HgCl₂ at room temperature in the ratio 1 / 1 /2.

The formula is determined by reňnement of the crystal structure and confirmed by chemical analysis. The structure consists of infinite alternated layers perpendicular to the b axis and chains parallel to the a axis and built up from HgCl₆ octahedra. Ammonium(or K⁺) cations and water molecules are sandwiched between the layers and the chains. The structure seems to be a superposition of the structure of the border compounds NH₄HgCl₃ and K₂HgCl₄.H₂O. The real formula is therefore that of the double-salt 4[K_0.635(NH₄)_0.365Cl]. 3HgCl₂. 2H₂O.

Perspective view of the structure K_2.54(NH₄)_1.46Hg₃Cl₁₀·2H₂O