Crystal Structure of Cesium-Sodium Molybdate Dihydrate

Structure of CsNaMoO₄ · 2H₂O crystals formed in Cs₂MoO₄–Na₂MoO₄–H₂O system is determined by X-ray diffraction study. The unit cell parameters a = 6.379(2) Å, b = 8.631(2) Å, c = 13.670(2) Å, V = 752.6(3) ų, Z = 4, M = 351.87, (calcd) = 3.105 g/cm³, space group P2₁2₁2₁. The isle crystal structure is built of MoO₄ ^2-, Cs⁺, and Na⁺ ions. The Mo–O bond lengths lie within 1.756(2)–1.769(3) Å range. The OMoO bond angle is 109.45° on average. Three oxygen atoms of MoO₄ ^2- anion are involved in hydrogen bonds with water molecules., while the fourth O atom participates in the formation of Na polyhedra only. The octahedral environment of Cs⁺ ions is formed by oxygen atoms of MoO₄ ^2- anions, without participation of water molecules. The structure contains two crystallographically independent water molecules, whose tetrahedral coordination consists of two Na⁺ ions and two MoO₄ ^2- anions.