The crystal structure and changes of (NH4)1.4[Cu(NH3)2]0.3Br2 composition

Abstract

Abstract The crystal stucture of (NH4)1.4[Cu(NH3)2]0.3 · Br2 is composed from a NH4Br structure where part of NH4 + ions was replaced with NH3 groups. The Cu atoms statistically occupy the centre of a cubic unit cell, with Br− ions in its apexes resulting in the creation of linear [H3N–Cu–NH3]2+ units. The statistical weight of the cationic units is 0.13(1). The Cu–N and Cu–Br− bond distances are 2.0293(4) (2 ×) and 2.8699(5) (4 ×) Å, respectively. Microcrystalline preparations having the composition of (NH4)2(1 − x)[Cu(NH3)2] x Br2 (x = 0.0 to 0.92) show continuous logarithmic normal x vs. density dependence. The formula for calculation of x from density (Dm ) of crystalline and microcrystalline preparations was derived.