Extended Frameworks Encapsulating Facial {MoO3} Units: Syntheses and Structural Characterizations of Ba3(MoO3)3(H2O)(AsO4)2, SrMoO3HAsO4·H2O, and Sr(MoO2AsO4)2

Abstract

Three new alkaline earth metal molybdenum(VI) arsenates, Ba3(MoO3)3(H2O)(AsO4)2 (1), SrMoO3HAsO4·H2O (2), and Sr(MoO2AsO4)2 (3), have been prepared and structurally characterized by single-crystal X-ray diffraction and thermogravimetric analysis. Crystal data: 1, monoclinic, P21/c, a = 10.1814(2) A, b = 17.5553(1) A, c = 17.0799(1) A, β = 90.349(1)°, V = 3052.75(7) A3, and Z = 8; 2, monoclinic, C2/c, a = 15.1927(11) A, b = 10.2590(8) A, c = 9.6550(7) A, β = 121.877(1)°, V = 1277.9(3) A3, and Z = 8; 3, monoclinic, P21/c, a = 6.5904(3) A, b = 6.8592(3) A, c = 10.4472(5) A, β = 92.106(2)°, V = 471.94(6) A3, and Z = 2. Crystal 1 adopts a novel open-framework structure which is composed of isolated MoO6 and Mo(H2O)O5 octahedra linked by AsO4 tetrahedra, resulting in intersecting tunnels where Ba2+ cations reside. Crystal 2 has a layer structure in which MoO6 octahedra are corner-shared with HAsO4 tetrahedra forming infinite sheets parallel to the (100) planes. The Sr2+ cations and water molecules are between ...