| Abstract: | We describe chemical preparations and give crystal data for two new arsenatochromates: (NH4)3AsCr4O16 and K3AsCr4O16 isotypic with K3PCr4O16. Both are monoclinic (Cc) with the following unit cells: a = 9.724(5), b = 11.98(5), c = 14.88(5)Å, β 105.82(5)º for the ammonium salt and a = 9.323(5), b = 12.03(5), c = 14.62(5) Å, β 105.25 (5)º for the potassium salt. The main feature of these salts is the geometrical configuration of the finite AsCr4O16 anion: a central AsO4 tetrahedron sharing its four corners with CrO4 tetrahedra. Up to now, these salts are the first example of a quaternary arsenic in a finite anion. |
