Gold halide

Monohalides AuCl, AuBr, AuI are all crystalline solids with a structure containing linear zig-zag chains: ..-X-Au-X-Au-X-Au-X-... The X-Au-X angle is 180^o.

Trihalides The triiodide does not exist. AuCl₃ readily forms out of the elements at temperatures below 254^oC. It is a volatile red solid. The volatile species is the dimmer Au₂Cl₆.