Jor - 6-6-2008 at 05:15
I once order 500g zinc from a supplier in the UK. When I tried to zinc-plate a coin, it did not succeed.
So I wondered, what metal do I have here?
It looked about the same as my bismuth granules. The same form of granules.
However, I could not dissolve this metal in:
-concetrated nitric
-moderately concetrated nitric
-sodium hydroxide solution
-aqua regia
-hydrochloric acid concentrated.
In nitric it dissolved, but only very slowly. Same for aqua regia.
The metal is not shiny.
Today, I put some of the metal in 4mL 5% sodium hypochlorite solution. I made this alkali, by by adding approx 0,5mL 30% NaOH. After 30 seconds, a
bright orange suspension is obtained. So does anyone have an idea what metal I am having here? I first thought it was bismuth as well, because bismuth
trioxide is yellow/orange. However this can't be true, because I could hardly dissolve this metal in nitric acid, while my pure bismuth metal
dissolves quite easily in concetrated nitric acid.
Is it Mo or W maybe?
[Edited on 6-6-2008 by Jor]
not_important - 6-6-2008 at 05:25
Tried determining its specific gravity? Zn ~7,1 Bi ~9,8 Mo ~10,3 W~19,25 Ta ~16,7 Nb~8.6
woelen - 6-6-2008 at 11:29
It looks like very pure iron. The very pure metal dissolves in acid very slowly, this really is amazing. In a hypochlorite solution it is readily
oxidized, giving a brown/orange suspension of Fe2O3.nH2O in water.
Just to confirm it, add some of the liquid with the orange suspension to concentrated hydrochloric acid, such that the liquid becomes acidic. If the
liquid becomes bright yellow, then that is another piece of evidence that it is iron. If you add a solution of a thiocyanate, then it will turn deep
red if it is iron.
It is not Mo, Mo dissolves in moderately concentrated nitric acid, giving a strange red powder (I recently posted this as a riddle on sciencemadness).
The_Davster - 6-6-2008 at 16:36
Is it hard? Brittle? Does it shatter when hit with something?
Have any pictures?
Magpie - 6-6-2008 at 18:06
Is it magnetic?
Jor - 7-6-2008 at 03:13
The orange suspension became broen after 1 night, and all the solid had settled. After addition of some concentrated hydrochloric acid, a bright
yellow solution is obtained. Quite some chlorine gas evolved, wich indicates that not all hypochlorite, and maybe some chlorate (?), had reacted. I
think this is, because the brown solid effectively covered the remaining metal.
Addition of 2 small spatulas of potassium thiocyanate (2 minutes after adding HCl) gave no red color. Maybe this is, because chlorine wich is still in
solution, is oxidising the thiocyanate (no HCN evolution is hope? 
). I will try
again later.
5 minutes after KSCN adiition, the solution is shaken, and a white precitipate is observed, wich forms a white suspension.
I could not determe density. My scale is not precise.
The magnet my mother uses for keeping her needles together (you know, wich you use to repair clothes), did not 'attract' the metal.
The metal does not feel very dense.
This is a picture:
It's exactly the same form as my bismuth. Granular.
[Edited on 7-6-2008 by Jor]
Zinc - 7-6-2008 at 05:29
Try to melt it and see how hot does It have to be to melt.
not_important - 7-6-2008 at 06:00
Weight a fairly large amount, such as 50 grams, even a 10% accuracy on the specific gravity will tell you something.
Also consider it may be an alloy, and thus give confusing results if you are doing tests expecting a pure element.
Boil and then cool the solution before adding thiocyanate, the boiling should drive off chlorine. Add the thiocyanate as a concentrated solution,
small drop by drop, shaking after each addition.
try placing some on a bit of copper, and treating both with moderately strong HCl - 5 to 10 percent.
The_Davster - 7-6-2008 at 09:07
Try heating it in some conc. nitric, and if it dissolves add some bisulfite.