Tin mining Tin mining Tin mining began early in the Bronze Age, as bronze is a copper-tin alloy. Tin is a relatively rare element in the Earth’s crust, with approximately 2 ppm (parts per million), compared to iron with 50,000 ppm. Tin extraction and use can be dated to the beginnings of the Bronze Age around 3000 BCE, when it was observed that copper objects formed of polymetallic ores with different metal contents had different physical properties. The earliest bronze objects had tin or arsenic content of less than 2% and are therefore believed to be the result of unintentional alloying due
Tin(II) chloride to maintain the equilibrium towards the left-hand side (using Le Chatelier's principle). Solutions of SnCl are also unstable towards oxidation by the air: This can be prevented by storing the solution over lumps of tin metal. There are many such cases where tin(II) chloride acts as a reducing agent, reducing silver and gold salts to the metal, and iron(III) salts to iron(II), for example: It also reduces copper(II) to copper(I). Solutions of tin(II) chloride can also serve simply as a source of Sn ions, which can form other tin(II) compounds via precipitation reactions. For example, reaction with sodium sulfide produces