Copper in architecture used in residential and commercial building structures. Variations in color stem primarily from differences in the alloy chemical composition. Some of the more popular copper alloys and their associated Unified Numbering System (UNS) numbers developed by ASTM and SAE are as follows: In practice, the term ‘bronze’ may be used for a variety of copper alloys with little or no tin if they resemble true bronzes in color. Further information on architectural copper alloys is available. The criteria by which copper and copper alloys are selected for architectural projects include color, strength, hardness, resistance to fatigue and corrosion, electrical and
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