FLUX SYNTHESIS OF LIAUS AND NAAUS - CHICKEN-WIRE-LIKE LAYER FORMATIONBY INTERWEAVING OF (AUS)(N)(N-) THREADS - COMPARISON WITH ALPHA-HGS AND AAUS (A = K, RB)

From the reaction of Au with alkali metal polysulfide liquids, LiAuS a nd NaAuS were discovered. Orange crystals of LiAuS crystallize in the monoclinic space group C2/c, (no. 15), with a = 8.994(2) Angstrom, b = 8.956(2) Angstrom, c = 7.201(3) Angstrom, beta = 128.68(1)degrees, an d Z = 8. Light-yellow planks of NaAuS crystallize in the orthorhombic space group Ccca, (no. 68), with a = 14.658(5) Angstrom, b = 21.043(7) Angstrom, c = 7.118(4) Angstrom, and Z = 32. Both compounds contain i nfinite one-dimensional (AuS)(n)(n-) chains, featuring alternating sul fide anions and linear coordinated Au centers. In LiAuS, the chains ar e zigzag and fully extended and they pack in two mutually perpendicula r sets. In NaAuS, the same chains coil in an unusual fashion so that t hey become interwoven to form layers reminiscent of ''chicken-wire''. This novel coiling mode allows Au-Au contacts to form, which help to s tabilize the structure. The structural relationships between LiAuS, Na AuS, Na7Au5S6, AAuQ (A = K, Rb, Cs; Q = S, Se), and alpha-HgS are expl ored.