Theoretical study of ternary silver fluorides AgMF (M = Cu, Ni, Co) formation at pressures up to 20 GPa

Only several compounds bearing the Ag( ii ) cation and other paramagnetic transition metal cations are known experimentally. Herein, we predict in silico stability and crystal structures of hypothetical ternary silver( ii ) fluorides with copper, nickel and cobalt in 1 : 1 stoichiometry at a pressure range from 0 GPa up to 20 GPa employing the evolutionary algorithm in combination with DFT calculations. The calculations show that AgCoF 4 could be synthesized already at ambient conditions but this compound would host diamagnetic Ag( i ) and high-spin Co( iii ). Although none of the compounds bearing Ag( ii ) could be preferred over binary substrates at ambient conditions, at increased pressure ternary fluorides of Ag( ii ) featuring Cu( ii ) and Ni( ii ) could be synthesized, in the pressure windows of 7-14 and 8-15 GPa, respectively. All title compounds would be semiconducting and demonstrate magnetic ordering. Compounds featuring Ni( ii ) and particularly Co( ii ) should exhibit fundamental band gaps much reduced with respect to pristine AgF 2 . The presence of Cu( ii ) and Ni( ii ) does not lead to electronic doping to AgF 2 layers, while Co( ii ) tends to reduce Ag( ii ) entirely to Ag( i ). Only several compounds bearing the Ag( ii ) cation and other paramagnetic transition metal cations are known experimentally. Here, we predict as yet unknown AgMF 4 phases and their stability in function of pressure.