itchyfruit
Hazard to Others
Posts: 231
Registered: 15-6-2009
Member Is Offline
Mood: No Mood
|
|
Bismuth carbonate
I have a few(3) small containers of white powder,i believe one of them is Bi co3 (theirs a label that's about the right size for the jars) is their a
sure way of analysing these to identify which one is the Bi co3. none react with 5%acetic acid and theirs no obvious change in flame colour when held
in a flame.
|
|
|
ammonium isocyanate
Hazard to Others
Posts: 124
Registered: 13-7-2009
Location: USA - Midwest
Member Is Offline
Mood: sick 
|
|
You could try a thermite reaction with aluminium (I think this step would work but I'm not certain) and then dissolve the resulting metal in hot
nitric acid (careful!). Addition of sodium hydroxide would produce a yellow precipitate of bismuth trioxide if the starting material was bismuth
subcarbonate.
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
Any idea what the other possible compounds are? I feel it may be easier to work out which is BiCO3 by process of elimination.
|
|
|
itchyfruit
Hazard to Others
Posts: 231
Registered: 15-6-2009
Member Is Offline
Mood: No Mood
|
|
I'll try some Naoh now. thanks
sorry no idea what the others might be,the only label was for Bico3. I thought if i could work out which one is Bico3 that will narrow down the
possibility's for the others to just a million or so 
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
If you have NO idea what the others are then be VERY careful. They could be very nasty chemicals indeed.
|
|
|
itchyfruit
Hazard to Others
Posts: 231
Registered: 15-6-2009
Member Is Offline
Mood: No Mood
|
|
I'm fairly sure they were brought from a chemist shop (in the 60's) they came in what i would describe as a extended childs chemistry set.
The most dangerous chemicals i've found in it so far are ammonium bichromate, potassium permanganate, litharge, and lead carbonate.
Their is a packet of Sepia toner but wiki doesn't seem to have much info on that!!
But yes i will be careful.
|
|
|
The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
Member Is Offline
Mood: .
|
|
Perhaps just try to calcine to Bi2O3 which is a yellow powder. Not totally indicative of course, but it is a start.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
1) Google for mineralogy charcoal tests bismuth you will get links for several old books from Google books and the Internet
Archives. Download one or more, you find a number of simple tests that can be useful for quickly identifying stuff like bismuth compounds.
2) dissolve a small bit of the carbonate in HNO3 or HCl, then dropwise add some solution of NaI or KI, dark grey/black/reddish BiI3 and/or BiOI will
precipitate. BiO is more red than BiI3, which you gets depends on concentrations and pH. There's not a lot that a soluble iodide will precipitate,
AgI is pale yellow and darkens in strong light, PbI2 is clearly yellow.
|
|
|
woelen
Super Administrator
Posts: 8027
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
A very sensitive test for bismuth is making the tetra-iodo complex of this. Try to dissolve some of the so-called bismuth carbonate in nitric acid
(25%) or in 30% HCl. Then add a small amount of KI. At once a black precipitate of BiI3 is formed. If you add more KI, then a beautiful intensely
colored orange complex is formed, BI4(-). If you dilute the liquid (making the acid more dilute), then the complex hydrolyzes and a precipitate of
hydrous Bi2O3 is formed. From my experience I know this reaction is quite sensitive and if there is bismuth in the sample, then it definitely works.
This set of pages may be interesting for you: http://woelen.homescience.net/science/chem/exps/Bi+halogen/i...
|
|
|
ammonium isocyanate
Hazard to Others
Posts: 124
Registered: 13-7-2009
Location: USA - Midwest
Member Is Offline
Mood: sick
|
|
Just so you know, that whole post of mine was one process. I don't think direct addition of NaOH to BiCO3 (if that's what you thought I meant) would
do anything.
|
|
|
itchyfruit
Hazard to Others
Posts: 231
Registered: 15-6-2009
Member Is Offline
Mood: No Mood
|
|
Thanks guys,
I'll try some of your suggestions tomorrow!!
Ammonium isocyanate, yes nothing happened when added to naoh. (now i've read the post properly i'll give it another go)
I heated the tube containing acetic acid and (bico3?) and before it even started to boil everything just blew out the end of the tube ??
Woelen, That's a great site, i don't know how you find the time to do it, but i'm well glad you do 'nice one'
|
|
|
JohnWW
International Hazard
Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
I doubt that its stoichiometric formula could be BiCO3, unless it contains a 1:1 mixture of Bi(I) and Bi(III). It is more likely to be either
Bi2(CO3)3, or more likely (BiO)2CO3 in view of how susceptible Bi(III) salts are to alkaline hydrolysis. Bi(II) compounds, which would contain
unpaired p electrons are unheard of. The only other way in such there could be such a stoichiometry is if there are Bi-Bi bonds, which is somewhat
unlikely.
|
|
|
itchyfruit
Hazard to Others
Posts: 231
Registered: 15-6-2009
Member Is Offline
Mood: No Mood
|
|
I consider myself 'blinded by science' that was way above my head, but it only said Bismuth carbonate on the label and i just wrote it in the
simplest formula!!
Off topic but is their a band in NZ that has the name/word Shem in it? My son wants a t-shirt. !!!
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
