Existence of Au- in compound KAu 5

The alkali-metal-gold compounds were formerly regarded as alloys and then they were generally named intermetallics. Their characteristics regularly change with the ratio of alkali-metal to gold and the increase of alkali-metal’s atomic number. However, on the basis of electrochemistry, M(?)ssbauer and X-ray photoelectron spectroscopic studies on alka-li-metal (K, Rb, Cs)-gold solutions of liquid ammonia and ethylenediamine and on the (2,