Estanho: um metal estratégico ontem e hoje

Abstract

Tin chemistry sometimes is considered boring, colourless and with irrelevant applications. Archaeological, historical and technological facts show otherwise. These facts demonstrate that tin became vital for man in a distant past and its importance lasts thereafter. In this paper, it is introduced some historical arguments that reveal the significance of tin or cassiterite as strategic materials in ancient tools, beginning from the Bronze Age. This paper shows as well the importance of this metal in current times. It also describes the importance of Brazil in this scenario, given the large reserves of cassiterite and its crucial participation in the world market. In addition, it provides a revision of the main classes of tin compounds {Sn (IV) and Sn (II), among other oxidation states}. Additionally, it summarises some main applications of tin compounds, such as PVC stabilizers, antifouling paint and in the manufacturing of foams and polymers, discussing its strategic role in modern technologies. Finally, it highlights the importance of tin in the preparation of Nb3Sn, a superconducting alloy with niobium, and in the synthesis of new materials, for example, a two-dimensional polymer, structurally similar to graphene.