Perhaps what needs to be explained in
simple terms is that both metal ions ( for example Cr+6, Cr+3, etc
) or a metals (valance=0, for example Cr ) may formcompounds.
For example, Cr+6 could be in the form
of an acidic chrome salt in solution or a solid component of a compound
such as a pigment or chromate coating on copper, steel, etc.
Chrome metal could be an element or
a compound such as an alloy such as stainless steel (generally containing
Fe, Ni, Cr, C, etc).
As Lu mentions, valance state
or existent state are different property descriptions and
are neither exclusive or inclusive.
Practical
If anyone needs a comprehensive listing
of Cr+6 (or other RHoS) compounds, I have compiled one and will share with
TGA members, but you must e-mail to me since we can't attach documents
on TGA server.
Regards,
C.B. Katzko, CTO
Meadville Group
e-mail [log in to unmask]
tel +86 21 3774 7528
fax +86 21 3774 7590
mobile +86 13817362590
As far as I'm concerned, there is no connection between the chemical valence
and the exsitent state of element. They are totally different concepts.
Cr6+ can be exist by the state of compound or positive ion
Best Regards,
Lucas Yao
R&D Electronic Engineering Design Section
Emerson Network Power Co., Ltd.
Tel: 86-755-8601-1568 Fax: 86-755-8601-0261
Website: www.emersonnetworkpower.com.cn
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Cr6+ 應該是以化合物的形式存在吧, 生成化合物後是不是還算離子狀態就不肯定了!
Hermus Leung
Technical Service Engineer, 3M Hong Kong
Victoria Centre, 5/F., 15, Watson Road, Hong Kong
Fax : (852) 2969-5758
Tel : (852) 2806-6407
eMail : [log in to unmask]
Ziyi Li
<liziyi@DAREWINCH
IP.COM>
To
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Subject
01/02/2008 05:00 [TGA] RoHS管制+6价的Cr，为何是离子
PM
态的管制？
Please respond to
Asia Committe
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Please respond to
liziyi@DAREWINCHI
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Dear All：
为什么RoHS管制+6价的Cr?在我认为：固态的产品（电镀层）如何出现离子态，很
另人困惑~,恳请各位支招!
谢谢!
Best Regards
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