Aggie - please.
There is no chromium in benzene rings, not does chromium form 6-atom rings. A benzene ring is a ring of six carbon atoms with a special type of bonds between them. No other element than carbon can form these bonds. There are other 6-atom carbon rings too which are not benzene, due to the lack of covalent bonds.
Let's count the charges: Potassium dichromate is K2Cr2O7. Each K is 1+, each O is 2-. That's 14- + 2+ = 12- . So each of the two Cr must be 6+ to balance the charges. Hexavalent = 6+!
I'm tempted to suggest you retake your college level chemistry...
Yep that is what I get for being over tired, and on migraine meds. You guys are right. I only thought quickly instead of grabbing my books and looking up. I didn't think past di vs. hex. I know better, but failed miserably.
Ok so in pentinence here is the Merck Index summation:
Human Toxicity: Internal a corrosive Poison. Industrial (rmember exposure level) may result in ulcerations of hands, destruction of mucous membranes and perforation of nasal septum. See E Browning, Toxicity of Industrial Metals (Appleton-Century Crofts, New York, 2nd ed., 1969) pp 119-131 See also Chromium.
Use: In tanning leather, dyeing, painting, decorating porcelain, printing, photolithography, pigment-prints, staining wood, pyrotechnics safety matches: for bleaching palm oil, wax nd sponges: waterproofing fabrics: as oxidizer manufacture of organic chemicals: in electric batteries: as depolarizer for dry cells. As corrosive inhibitor in preference to sodium dichromate where lower soly is advantageous. Pharmaceutic aid (oxidizing agent)
If you look at the list of uses, we come in contact with it in minimal amounts in various forms. The last on the list is interesting in that in what would be minute amounts it is used int he pharmacuetical industry, or in other words at some point we are putting it in our bodies. Again I want to stress know what you are reading. The industrial useage is a massive exposure. And don't do like I do and make stupid mistakes with chemistry.