The crystal structure of diaquobis(acetylacetonato)magnesium(II)

BaA1204 single crystals are hexagonal with a= 10.444 + 0.002, c= 8"793 + 0"002 A, the a axis being doubled compared with the previously reported value.Single crystals of BaAlzO4 were grown from a barium borate flux.The starting materials were melted in a platinum crucible which was heated to 1275°C in a globar furnace.The crystals were grown by slow cooling of the melt at a rate of 2 °C per hour.Single crystals grew in the shape of clear hexagonal rods (3 mm long x 0.5 mm diameter) parallel to the c axis and bounded by {10i0} and {0001 } faces.Single-crystal X-ray photographs showed very weak additional reflections which required a doubling of the hexagonal a axis compared with the unit cell reported by previous workers on polycrystalline material (Wallmark & Westgren, 1937; Do Dinh & Bertaut, 1965)*.A similar doubling of the a axis in this structure type has been found in single crystals of BaGa204 (Hoppe & Schepers, 1960).Lattice constants a= 10.444+ 0.002 A, c= 8.793 + 0.002 A * These authors reported space group P6322.The structure is described (Strukturbericht, 1937) as type H28.were obtained by a least-squares fit of the back reflection powder diffraction lines.The authors wish to thank P. G. Herkart and F. S. Stofko for their assistance in growing the crystals and R.J.Paff for the X-ray powder diffraction data.