Syntheses and Structures of Two Ammonium Zinc Gallophosphates: Analcime and Paracelsian analogs

Two ammonium zinc gallophosphates (I) (NH 4 ) 16 [Zn 16 Ga 8 P 24 O 96 ] and (II) (NH 4 ) 4 [Zn 4 Ga 4 P 8 O 32 ] were hydrothermally synthesized and characterized using single crystal X-ray diffraction. The (I) (NH 4 ) 16 [Zn 16 Ga 8 P 24 O 96 ] crystallizes in a cubic I 2 1 3 space group ( a =13.456(1) A, V =2436.5(5) A 3 , R (on F )=2.47%, R w (on F )=2.48%). It has a zeolite analcime topology with distorted eight-member ring channels. Zn and Ga atoms share the same crystallographic site with a partial occupancy of Zn/Ga=0.67/0.33. Ammonium ions lie on the three-fold crystallographic axes and compensate for a negatively charged framework. The second compound (II) (NH 4 ) 4 [Zn 4 Ga 4 P 8 O 32 ] has a monoclinic symmetry ( P 2 1 /a, a =9.406(1) A, b =9.881(1) A, c =8.612(1) A, β =90.58(1)°, R (on F )=2.7%, R w (on F )=3.0%). It is isostructural with a feldspar paracelsian. Zinc and gallium occupy two crystallographic sites with a partial occupancy of Zn(1)/Ga(1) =0.53(6)/0.47(6) and Zn(2)/Ga(2)=0.47(6)/0.53(6). Ammonium ions lie in the elliptical eight-member ring openings of the three-dimensional framework.