Unexpectedly Complex Crystalline Phases in the MSO sub(3)F-Ag(SO sub(3)F) sub(2) Phase Diagram (M = Na, K, Rb, Cs)

The syntheses and characterizations of mixed-cation fluorosulfates containing Ag super(II) ions are reported and add to the moderately well-known chemistry of Ag super(II) compounds. The compounds synthesized mostly show different structures and compositions. The mixed sodium-silver fluorosulfate is isostructural with Ag sub(3)(SO sub(3)F) sub(4 ) (monoclinic P2 sub(1)/c, a = 5.2812 Aa, b = 13.0473 Aa, c = 19.3557 Aa, and beta = 100.970 degree ) and has the composition (Ag sub(0.05)Na sub(0.95))(Ag sub(0.65)Na sub(0.35))Ag super( II)(SO sub(3)F) sub(4). The mixed potassium-silver fluorosulfate does not correspond to K super(I) sub(2)Ag super(II)(SO sub(3)F) sub(4) but rather to KAg super(I) sub(2)Ag super(II)(SO sub(3)F) sub(5) [orthorhombic P222 sub(1), a = 6.4736(3) Aa, b = 7.3915(4) Aa, and c = 17.7736(10) Aa]. Two rubidium-silver fluorosulfates form as a mixture, one corresponds to RbAg super(I) sub(2)Ag super(II)(SO sub(3)F) sub(5) [orthorhombic P222 sub(1), a = 6.4828(6) Aa, b = 7.3551(7) Aa, c = 18.0262(17) Aa], and the other corresponds to RbAg super(II)(SO sub(3)F) sub(3) [monoclinic P2 sub(1)/m, a = 15.8152(14) Aa, b = 15.4861(13) Aa, c = 17.0211(14) Aa, and beta = 101.513(5) degree ]. The cesium fluorosulfate/silver(II) fluorosulfate phase diagram is exemplified by the CsAg super(II)(SO sub(3)F) sub(3) salt [triclinic P $\bar {1}$[Imageomitted] , a = 14.9241(5) Aa, b = 9.7046(3) Aa, c = 17.8465(7) Aa, alpha = 109.116(2) degree , beta = 84.655(3) degree , and gamma = 119.171(3) degree ]. The IR and Raman spectra of the compounds were measured, and their thermal stability and magnetic properties have been determined. The MAg super(I) sub(2)Ag super(II)(SO sub(3)F) sub(5) systems show antiferromagnetic behavior with absolute superexchange constants of up to 19.1 meV for M = K, and ferromagnetism can be observed below 20-40 K for the MAg(SO sub(3)F) sub(3) derivatives (M = Rb, Cs). The ability of the fluorosulfate anion to form complex paramagnetic salts with alkali metal and Ag super(II) cations has been scrutinized. The SO sub(3)F super(-) anion efficiently transfers magnetic superexchange between Ag super(II) centers in complex MAg super(I) sub(2)Ag super(II)(SO sub(3)F) sub(5) antiferromagnets, and the superexchange constant reaches -19.1 meV for the K salt.