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<p>[QUOTE=&quot;Tom B, post: 871593, member: 11854&quot;]<b>No. This is incorrect.</b></p><p>&nbsp;</p><p>Look, your intentions are <i>good, </i>but you don&#039;t have the details correct. I&#039;ll go through a bit of this for you, but if you don&#039;t understand what I am writing please send me a PM instead of muddying up the forums with misinformation.</p><p>&nbsp;</p><p>PVC and verdigris are two different things and the presence of one does not require the presence or influence of the other. They are compounds independent of one another. As you already know, PVC is a repeating monomer of vinyl chloride, which can be written as [-CH(2)-CHCl-] or alternatively C(2)H(3)Cl where the parentheses indicate subscripts. PVC is fairly stable in a cool, dark and relatively dry environment, but when random chlorine atoms dissociate from the PVC chain and react with compounds such as hydronium ions they can form tiny quantities of strong acids. It&#039;s this localized production of acid that can attack the surface of a coin to etch it and deposit the familiar PVC slime. This PVC slime has previously been characterized as copper phthalate. The reaction rate is quite slow, but one must realize that within each PVC chain there are generally from 950 to 2,500 atoms of chlorine (one for each vinyl group).</p><p>&nbsp;</p><p>Verdigris, on the other hand, is a mixed bag of copper salts including copper acetate, copper chloride, copper carbonate and other materials. The list is not entirely consistent and will change depending on the environment or other factors, I would assume. The chlorine that is present in some forms of verdigris need not come from PVC and I would imagine that nearly any ancient site that has evidence of verdigris had this compound form in the absence of PVC.</p><p>&nbsp;</p><p>I realize you have some experience handling these compounds and that we don&#039;t know who you are or what you&#039;ve done. That&#039;s fine, but I know my experience and training and I know that I understand this field to a depth that is not for everyone. If you want to know more and have questions, please send me a PM.[/QUOTE]</p><p><br /></p>

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