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Hexavalent Chromium (Cr+6)

Restriction of hazardous substances (RoHS) and 'waste electrical and electronic equipment' (WEEE) directives on the lead, mercury, cadmium and hexavalent chromium content of stainless steels

he European directive 2002/95/EC was originally published on 27th January 2003 and came into force on 13th February 2003. It required that EC member states transpose the directive into their national law by 13th August 2004 so that new electrical and electronic equipment ('which is dependant on an electric current in order to work properly'), put on the market from 1st July 2006 did not contain ANY lead, mercury, cadmium, hexavalent chromium, poly-brominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE).

Does the chromium in stainless steel contain 'chrome 6' (Cr6+ ) and is this a potential health hazard

The valency (oxidation state) of chromium metal as an alloying constituent of stainless steels is 0 (zero). Chromium atoms are present in stainless steels in 'substitutional' lattice positions, replacing iron atoms. This is the same as other 'large' atoms from elements such nickel. The atoms are held together in the lattice structure by the 'metallic bond'. This involves the sharing of electrons between atoms with no loss or gain of electrons from atom to atom. The valency state is therefore taken as 0 (zero).

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