(NH4)Ga(HAsO4)2 and TlAl(HAsO4)2 - two new RbFe(HPO4)2-type M+M3+ arsenates

• Main Authors: Karolina Schwendtner, Uwe Kolitsch
• Format: Article
• Language: English
• Published: International Union of Crystallography 2018-10-01
• Series: Acta Crystallographica Section E: Crystallographic Communications
• Subjects: crystal structure; (NH4)Ga(HAsO4)2; TlAl(HAsO4)2
• Online Access: http://scripts.iucr.org/cgi-bin/paper?S2056989018013567

The crystal structures of hydrothermally synthesized (T = 493 K, 7–9 d) ammonium gallium bis[hydrogen arsenate(V)], (NH4)Ga(HAsO4)2, and thallium aluminium bis[hydrogen arsenate(V)], TlAl(HAsO4)2, were solved by single-crystal X-ray diffraction. Both compounds crystallize in the common RbFe(HPO4)2 structure type (R\overline{3}c) and share the same tetrahedral–octahedral framework topology that houses the M+ cations in its channels. One of the two Tl sites is slightly offset from its ideal position. Strong O—H...O hydrogen bonds strengthen the network.