Ag^IISO₄: A Genuine Sulfate of Divalent Silver with Anomalously Strong One‐Dimensional Antiferromagnetic Interactions

Abstract

Schwarzes AgSO4, das erstmals durch eine Austauschreaktion synthetisiert wurde, unterscheidet sich erheblich von den wasserfreien Sulfaten anderer Elemente der Gruppe 11: Es hat eine sehr schmale elektronische Bandlücke (ca. 0.2 eV) und eine außergewöhnlich starke eindimensionale antiferromagnetische Ordnung (J≈10 meV pro Ag), die bis zum Beginn der thermischen Zersetzung bei etwa 120 °C erhalten bleibt. Ag grau, O rot, S gelb.

Unusual Thermal Decomposition of AgIISO4 Yielding AgI2S2O7: Bending Hammond’s Rule

“…Clearly, sulfates of divalent Ag and Cu do not share many important physicochemical features. [4] The analysis of literature data for over 50 different sulfates and oxo-sulfates of the main group and transition metals (see the Supporting Information) reveals that Ag II SO 4 is unique as far as thermal decomposition is considered. Although other sulfates decompose by desulfation, AgSO 4 undergoes low-temperature "reductive decomposition" (i.e., a process in which the metal cation is reduced while O 2 is eliminated).…”

“…We show, based on literature about thermal decomposition for over 50 different sulfates and oxo-sulfates (see the Supporting Information), that solely AgSO 4 s low-temperature thermal decomposition is associated with the reduction of a metal cation ("reductive decomposition"). We consider the reaction pathway for decomposition and we point out structural links between Ag II SO 4 and crystalline product of its decomposition, AgSO 3. [4] 4Ag II SO 4 !…”

“…We consider the reaction pathway for decomposition and we point out structural links between Ag II SO 4 and crystalline product of its decomposition, AgSO 3. [4] 4Ag II SO 4 ! 2Ag…”

“…Thus Ag II is stabilized in connections with fluoride ligands, [2] whereas its oxo and aza compounds are rare and are quite unstable thermodynamically and thermally. [3,4,5,6,7,8] Here we investigate in detail the thermal decomposition of recently synthesized Ag II sulfate, AgSO 4 . [4] The activation energy for decomposition turns out to be substantial (%127 kJ mol…”

“…[3,4,5,6,7,8] Here we investigate in detail the thermal decomposition of recently synthesized Ag II sulfate, AgSO 4 . [4] The activation energy for decomposition turns out to be substantial (%127 kJ mol…”