Titelbild: Ag^IISO₄: A Genuine Sulfate of Divalent Silver with Anomalously Strong One‐Dimensional Antiferromagnetic Interactions (Angew. Chem. 9/2010)

Abstract

Tiefschwarzes AgSO4 (Mr. Hyde) ist ein Halbleiter mit schmaler Bandlücke und ein extrem starkes Oxidationsmittel. W. Grochala und Mitarbeiter zeigen in ihrer Zuschrift auf dass AgSO4 in praktisch allen physikochemischen Eigenschaften von seinem leichteren Verwandten, dem unreaktiven und farblosen CuSO4 (Dr. Jekyll), abweicht. Die ungewöhnlich starke antiferromagnetische Kopplung bleibt bis zur Zersetzungstemperatur (ca. 120 °C) erhalten, wodurch es sich auch von allen anderen Übergangsmetallsulfaten unterscheidet.

Silver(II) Fluorosulfate: A Thermally Fragile Ferromagnetic Derivative of Divalent Silver in an Oxa‐Ligand Environment

“…The short Ag-O separations are close to those found for other oxo compounds of divalent silver, such as Ag II (AgO 2 ) 2 (2.052-2.086 Å) [4] or Ag II SO 4 (2.094-2.198 Å). [7] Regretfully, the crystal structure of related Cu(SO 3 F) 2 is not available for comparison.…”

“…In consequence, Ag II -[Ag III O 2 ] 2 is supposedly metallic [4] whereas AgSO 4 shows an unusually strong antiferromagnetic (AFM) coupling, which persists up to the temperature of thermal decomposition of this compound. [7] The remaining Ag II (SO 3 F) 2 [5] and Ag II (SO 3 CF 3 ) 2 [6] were only partially characterized in the previous literature reports: (i) limited data is available on the positions of IR bands; (ii) the value of the Curie temperature for ferromagnetic Ag II (SO 3 F) 2 was initially given as 20 K [5] but was then inconsistently reported as 40 K elsewhere. [9] Crystal structures and other important properties of this compound were not studied.…”

“…Due to the paucity of Ag II complexes as well as to extend our previous work on compounds of silver(II) with oxa ligands, [7,10] we explored various synthetic pathways and thoroughly characterized the chemical reactivity and physical properties of pseudobinary fluorosulfate and triflate derivatives of Ag II . In the current work we report the crystal structure of Ag II (SO 3 F) 2 , full vibrational (IR and Raman) and electron spin resonance (ESR) spectra, characterize its magnetic and thermal properties and interpret our findings with the help of periodic DFT calculations.…”

“…Indeed, theoretical DFT calculations predict that Ag II is capable of transferring the hole from its 4d 9 set to the 2p band of oxygen in many pseudobinary inorganic connections in the gas phase. [3] Nevertheless, several thermodynamically metastable derivatives of Ag II in the solid state with oxygen in the first coordination sphere of a metal have been reported, notably Ag II [Ag III O 2 ] 2 , [4] Ag II (SO 3 F) 2 , [5] Ag II -(SO 3 CF 3 ) 2 , [6] AgSO 4 [7] and Ag II (pz) 2 (S 2 O 8 ), in which pz = pyrazine. [8] The electronic and magnetic properties of oxa derivatives of Ag II are often surprising due to substantial 4d(Ag)-2p(O) orbital mixing, which vastly exceeds the one seen for analogous Cu II oxide derivatives.…”

Stark antiferromagnetische eindimensionale Wechselwirkungen von Silber(II)‐Ionen in AgSO4

“…B. Cs 2 AgF 4 , [4] das kürzlich großes Interesse hervorgerufen hat, da es bei tiefen Temperaturen ferromagnetische Ordnung zeigt. [5] In [10] Nun berichteten Malinowski et al [11] über die Synthese von schwarzem AgSO 4 [12] wie man es für ein vierfach von O-Atomen koordiniertes Ag 2+ erwartet, [9] und somit ist AgSO 4 [15] ergibt für den magnetischen Superaustausch einen sehr hohen J-Wert von 217 K, ähnlich dem, der für verschiedene eindimensionale Verbindungen mit Cu 2+ [16] und für das zweidimensionale quadratische antiferromagnetische Heisenberg-Gitter in [Ag(pyz) 2 (S 2 O 8 )] [17] gefunden wurde. Wasserfreies CuSO 4 ordnet ebenfalls antiferromagnetisch, allerdings bei vergleichsweise niedrigen 36 K, wobei in diesem Fall die Ordnung nicht niedrigdimensional ist.…”