Hydrothermal synthesis, structure, and sorption properties of Cs(H 3O)[Mo 2O 2(PO 4) 2(HPO 4)

Abstract

Yellow plates of Cs(H 3O)[Mo 2O 2(PO 4) 2(HPO 4)], (1), obtained in 60% yield from the reaction of Cs 2MoO 4, Mo, H 3PO 4, and H 2O in a mole ratio of 5:1:30:57 for 24 hrs at 200°C, crystallize in the monoclinic space group P2 1 a with a = 9.166(4), b = 9.073(2), c = 15.808(3)Å, β = 96.85°, V = 1305(1)Å 3, Z = 4, and R( R w ) = 0.087(0.085). The structure has MoOPO 4-like layers held together with HPO 4 groups and is structurally similar to (VO) 2(SO 4) 2(H 2SO 4). The interlamellar space is compartmentalized into tunnels containing one-dimensional H-bonded strings of HPO 4 groups alternating with strings of Cs + and H 3O + cations. It is possible to remove water from the structure in a reversible manner as shown from water absorption isotherms. This same composition framework was prepared in a different crystal system and with a different cation by Clearfield and Peascoe (see J. Solid State Chem. 95(1), 83 (1991)).