The reaction kinetics and Sn isotope fractionation of Sn(IV) chloride hydrolysis

• Published in: Applied geochemistry Vol. 158; p. 105793
• Main Authors: She, Jia-Xin, Li, Weiqiang, Cai, Yuanfeng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2023
• Subjects: Activation energy; Cassiterite; chlorides; equations; geochemistry; Hydrolysis; ionic strength; isotope fractionation; isotopes; Kinetics; mineralization; reaction kinetics; reaction mechanisms; Sn isotopes; Sn(IV) chloride; temperature; Hydrolysis; Sn isotopes; Kinetics; Cassiterite; Activation energy; Sn(IV) chloride
• ISSN: 0883-2927; 1872-9134
• DOI: 10.1016/j.apgeochem.2023.105793

Hydrolysis of Sn is a pivotal step during the precipitation of cassiterite, the primary Sn-bearing mineral and thermodynamically stable Sn-oxide on Earth's surface. In this contribution, we investigated the reaction kinetics of Sn(IV) chloride hydrolysis by systematic experiments at temperatures of 6.4 °C to 28.6 °C. Experimental results show that the hydrolysis reactions of Sn(IV) chloride follow a first-order kinetics model, with rate constants (0.12 h−1 to 5.5 h−1) strongly controlled by temperature. Based on the obtained reaction constants at different temperatures and the Arrhenius equation, the activation energy of the Sn(IV) chloride hydrolysis reaction is calculated to be 26.05 ± 2.25 kcal/mol, indicating a surface-controlled reaction mechanism. Additionally, the Sn(IV) chloride hydrolysis rate increases with the ionic strength. No significant Sn isotope fractionation between aqueous Sn(IV) and the solid hydrolysis product was observed during the Sn(IV) hydrolysis experiments in this study. The activation energy data and Sn isotope behavior associated with Sn(IV) chloride hydrolysis may be used to better understand the behavior of Sn during various mineralization and weathering processes. •Determined Sn(Ⅵ) chloride hydrolysis rates under various temperatures and ionic strengths.•First report of activation energy for the Sn hydrolysis reaction.•Nanoparticles of Sn hydrolysis product for enhanced Sn transport in fluids.•Sn isotope fractionation during the Sn hydrolysis process is insignificant.