From Cs2Mo6Cl14 to Cs2Mo6Cl14·H2O and Vice Versa: Crystal Chemistry Investigations

International audienceWe report here the synthesis, the crystal structure and the luminescent properties of the new cluster compounds Cs2Mo6Cl14.H2O and Cs2Mo6Br14.H2O. Single-crystal X-ray diffraction performed on Cs2Mo6Cl14.H2O indicates that the compound crystallizes in the monoclinic space group C2/c with refined cell parameters a = 19.578 Å, b = 15.151 Å, c = 9.347 Å, and = 115.64°. The structure can be described from discrete [Mo6Cl i 8Cl a 6] 2-anionic cluster units arranged in a "A-A'-A-A'" pseudo prismatic stacking parallel to (b,c) plane with both Cs + cations and water molecules located between the layers. The centric character of the trigonal structure of Cs2Mo6Cl14 was also studied by combination of single-crystal X-ray diffraction and both X-ray and neutron powder diffraction. The results suggest an important influence of the sample preparation on the symmetry of the crystal structure. The crystal structure relationship between the [Mo6Cl i 8Cl a 6] 2-anionic cluster unit arrangements in Cs2Mo6Cl14 and Cs2Mo6Cl14.H2O is discussed. Finally, the characterization of the luminescent properties of Cs2Mo6X14 and Cs2Mo6X14.H2O (X = Cl, Br) indicates that emission profile is comparable regardless existence of water molecule in the crystal structure