[jdurg]

My iridium button arrived today so I was finally able to take a picture of it.  (Soon I'll be able to take a real good picture of it and update the Periodic Table with it).  After taking it out of the packaging I was AMAZED at how dense it is.  This is incredible.  I am so happy to finally have over one troy ounce of 99.98% pure Ir metal.  Thank god for football pools.    Anyway, when I took a quick picture of it I put a one troy ounce silver coin right next to it.  The thickness of the two items are vitually identical, and the Ir is maybe 1-2 mm thicker at the high spot.  The Ir weighs 35 grams and the Ag weighs 31 grams (maybe 32 with the holder included).  As you can see, the Ir is MUCH smaller than the Ag is.  Simply amazing.  Also, in the bigger size it's a bit easier to see the yellow tinge that Ir has.  When I put the Ir near the Os and Pd samples I have, the blueness of the Os really shines, the yellow tinge the Ir has shows through, and the blazingly whiteness of the Pd shows itself.  THIS is why I collect the elements.  

[movies]

That's a beautiful sample you have there.

Is palladium really white?

[jdurg]

Pretty much.  I had always heard the term 'white-metal' before but never really paid much attention to it.  However, if you have a nice chunk of palladium and put it near a sample of something like silver or tin, the palladium just appears much brighter and 'whiter' than the other metals.  It's kind of hard to explain.  Platinum and rhodium are nice and 'white' as well too.

[movies]

That's interesting.  I work on a lot of palladium catalysis and we often see elemental palladium precipitate out of failed reactions.  It always appears as either a dark black powder (like ash) or as a shiny film on the sides of the vial or flask, the so-called "palladium mirror."  The mirror is certainly nice to look at, but of course it usually means your reaction failed.

Do you keep your palladium in an inert atmosphere all the time?  We have a fair amount of trouble when we use palladium(0) sources in the air since they oxidize pretty readily to palladium(II).

[Mitch]

Jdurg: Nice sample.

movies: Our Palladium reaction junk might be an other allotrope of Pd.

[jdurg]

My Pd is sealed inside of the assay card it came in, so I'm not sure if that atmosphere is "inert".  When you have any metal ppt-ing out of solution, it will always appear much different than the bulk metal does.  Take gold for example.  When gold is precipitated out of solution during the refining process, it's a dark brown/purple/black sludge that looks nothing like the gold we all know and love.  This is because of the very small particle size and how it is optically different than the bulk metal.