At my school today, i was doing some Halogen Halide reactions, and also, the reaction of a Halogen with Silver Nitrate. I spilt some of the solution containing Ag+ and Cl- ions on the edge of a test tube (i presume), but didn't notice, and must have come into contact with it. Upon getting home tonight i now have a silver/grey looking patch on my little finger (about the area of a british 5 pence coin), has the Silver Chloride, produced silver due to light exposure, some how in my skin? Is this dangerous?

 

Thanks Alex

Yes, you are correct. Silver halides are very light sensitive and decompose into their silver salt, and the free halogen. (Though the free halogen typically binds VERY rapidly with something else to become fairly innocuous). The grayish/brown color you see are minute silver and silver sulfide (from the reaction with silver and sulfur-containing compounds in your skin) deposits in your skin.

 

Unless you rapidly poured a LOT of the silver solution on your skin (which would be fairly pricey) you aren't going to have any ill effects. Silver ions are a VERY good disinfectant, and there are my "high-tech" products that have a fine silver thread woven into them to provide disinfectant/deodorizing abilities. (I've heard of boxer shorts having silver linings to disinfect and get rid of stench).

 

AgNO3 (silver nitrate) was widely used to treat nosebleeds many years ago. It helped the wound heal, and disinfected it. The downside was that it left the silver/brown stain on your upper lip/nose and it eventually become too expensive compared to other disinfectants.

Ok thankyou for reassuring me.

don`t worry about it, I get that all the time in Photography and it`s quite harmless.

if you Know you have a spill on you and where it is, you can dab some Hypo (sodium thiosulphate) on the area and that will stop the black (silver particles) marking your skin, once it reacts and changes color though it`s too late and you have to wait a week or 2 for the stain to come out.

 

Gold in the form of Chloride is another such chem, only that gives you a Purple/black stain instead.

Ok, its no longer greyish it's gone completley black now, lol so looks like im stuck with a partially black finger for a while lol