Synthesis and characterization of NH4(Al0.64Ga0.36)(HPO4)2; a three dimensional anionic tunnel structure with charge balancing NH4+

Abstract

NH₄(Al_0.64Ga_0.36)(HPO₄)₂ was prepared hydrothermally and examined by single crystal X-ray diffraction. It consists of corner-sharing MO₆ octahedra and PO₄ tetrahedra and is structurally related to NH₄Fe(HPO₄)₂ but distinct from H₃O·Fe(HPO₄)₂ . The ammonium ions lie in a 3D connected network of tunnels with dimensions smaller than those found in zeolite A: a=7.109(4), b=8.695(4), c=9.252(6) Å, alpha;=65.01(4), beta;=70.25(5), gamma;=69.01(4)°, V=472.1(4) ų , space group P, Z=3, D_m=2.63 g cm^–3 , D_c=2.66 g cm^–3 , 168 parameters, 1916 reflections, R_F=0.056 (all data).