Bond-bending isomerism and metallophilicity in metal-halogen anions (Cu,Ag,Au) 2 X 3 - , X = F, Cl, Br, I, At.

In the framework of DFT (ABINIT package), we have performed atomic relaxations on the (Cu,Ag,Au)X , X = F, Cl, Br, I, At anion series. Opposite to linear (MX) anions, all (MX) systems are triangular ( symmetry). According to the system, we classified these anions in three categories according to the relative strength of electronegativity, chemical hardness, metallophilicity and van der Waals interaction. We found two bond-bending isomers: (AuI) and (AuAt).