The reaction of elemental gold and selenic acid in Teflon-lined steel autoclaves leads to orange-yellow single crystals of Au2(SeO3)2(SeO4) (orthorhombic, Z = 4, Cmc2(1) (No. 36), a = 1689.1(3) pm, b = 630.13(8) pm, c = 832.7(1) pm, V = 886.2(2) angstroms3, Rall = 0.0452). In the crystal structure, Au3+ is surrounded by four oxygen atoms of just as many monodentate SeO3(2-) ions in a square planar manner. The linkage of the polyhedra leads to double chains in the [001] direction which are connected to puckered layers by SeO4(2-) groups. The noncentrosymmetric space group could be proved by the observation of an SHG effect upon irridation at 1064 nm that shows an efficiency of about 43% compared to a KDP reference. Upon heating, Au2(SeO3)2(SeO4) decomposes at about 370 degrees C in one step yielding elemental gold. The presence of selenite and selenate groups in the compounds is also obvious from the IR and Raman spectra which show the characteristic bands of both species. Furthermore, solid-state NMR spectra reveal the different surroundings of the selenium atoms in the compound.

Yellow single crystals of (NO 2 )[Au(NO 3 ) 4 ] (monoclinic, P2 1 /n, Z ) 2, a ) 775.1(2) pm, b ) 810.2(2) pm, c ) 898.7(2) pm, β ) 112.67(3)°, wR2 ) 0.0622) were obtained from the reaction of elemental gold with N 2 O 5 . In the crystal structure complex [Au(NO 3 ) 4 ]ions are present with the Au 3+ ions being in square planar coordination of four oxygen atoms of just as many monodentate nitrate groups. Charge compensation is achieved by linear NO 2 + ions. (NO 2 )[Au(NO 3 ) 4 ] decomposes between 363 and 423 K in a complex process yielding elemental gold. Solutions of (NO 2 )[Au(NO 3 ) 4 ] in N 2 O 5 were used to build contamination free structures of elemental gold onto a silica surface by electron beam initiated decomposition of the compound.

Gelbe Einkristalle von (H5O2)[Au(NO3)4]·H2O bilden sich beim Abkühlen einer Lösung von Au(OH)3 in konz. Salpetersäure. In der Kristallstruktur (monoklin, C2/c, Z = 4, a = 1214, 5(2), b = 854, 4(1), c = 1225, 7(2) pm, β = 117, 75(1)°, Rall = 0, 0331) wird Au3+ von vier einzähnig angreifenden NO3—‐Ionen umgeben. Die [Au(NO3)4]—‐Einheiten werden von H5O2+‐Ionen zusammengehalten, die mit den H2O‐Molekülen über starke Wasserstoffbrückenbindungen verknüpft sind. Die thermische Analyse läßt auf einen fünfstufigen Abbau schließen und führt zu elementarem Gold.

The evaporation of a solution of Au(OH)3 and Na2SC>4 in conc. sulfuric acid led to yellow single crystals of NaAu(S04)2 (monoclinic, P2\/n, Z = 2, a = 469.1, b = 845.9, c = 831.2 pm, ß = 95.7°). Analogous procedures with K2SO4 or Rb2SC>4 instead of Na2SC>4 yielded single crystals of KAu(SC>4)2 (monoclinic, Cite, Z = 4, a = 1109.8, b = 724.2, c = 941.1 pm, ß = 118.4°) and RbAu(S04)2, respectively, (triclinic, PI, Z -1, a = 423.6, b -497.5, c = 889.0 pm, a = 76.4°, ß = 88.4°, 7 = 73.5°). Although the crystal structures of the three sulfates are not isotypic they show similar structural features: The gold atoms are coordinated by four oxygen atoms in a square planar manner. These oxygen atoms belong to four SC>42_ ions which link the [AUO4] units to infinite chains according to c^,[Au(S04)4/ 2]_ . These chains are connected via the monovalent cations which show coordination respectively.