Structural Features of Ag[AuF₄] and Ag[AuF₆] and the Stuctural Relationship of Ag[AgF₄]₂\nand Au[AuF₄]₂ to Ag[AuF₄]₂

Abstract

Synchrotron radiation X-ray powder diffraction data (SPDD) have been obtained for Ag[AgF₄]₂, Au[AuF₄]₂,\nAg[AuF₄], and Ag[AuF₆]. Ag[AgF₄]₂ and Au[AuF₄]₂ are isostructural with Ag[AuF₄]₂, space group (SG) <i>P</i>2₁/<i>n</i>,\n<i>Z</i> = 2, with the following: for Ag[AgF₄]₂ <i>a</i> = 5.04664(8), <i>b</i> = 11.0542(2), <i>c</i> = 5.44914(9) Å, β = 97.170(2)°;\nfor Au[AuF₄]₂ <i>a</i> = 5.203(2), <i>b</i> = 11.186(3), <i>c</i> = 5.531(2) Å, β = 90.55(2)°. The structure of Ag[AgF₄]₂ was\nrefined successfully (SPDD) applying the Rietveld method, yielding the following interatomic distances (Å): \nAg^II−F = 2.056(12), 2.200(13), 2.558(13); Ag^III−F = two at 1.846(12), others = 1.887(12), 1.909(13), 2.786(12), 2.796(12), 2.855(12). AgAuF₄, like other AA‘F₄ salts (A = Na−Rb; A‘ = Ag, Au), crystallizes in the\nKBrF₄ structure type, SG <i>I</i>4/<i>mcm</i> (140), <i>Z</i> = 4 with <i>a</i> = 5.79109(6), <i>c</i> = 10.81676(7) Å. SPDD gave (in Å) four\nAu^III−F = 1.89(1) and eight Ag^I−F = 2.577(7). SPDD for AgAuF₆ confirmed that it has the LiSbF₆ structure,\nSG <i>R</i>3̄, <i>Z</i> = 3, with <i>a</i> = 5.2840(2), <i>c</i> = 15.0451(6) Å.