vano
National Hazard
![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif)
Posts: 661
Registered: 22-3-2019
Location: Georgia
Member Is Offline
|
|
Potassium triiodoplumbate - K[PbI3]
I'm new hear. Hi everyone. Today i made Potassium triiodoplumbate K [PbI3]. It is a light yellow crystals, soluble in water, forms a crystalline
hydrate. I have dihydrate which begins to lose water at 30 ° C. There are some reactions:
I used lead acetate trihydrate.
1) Pb(CH3COO)2 + KI → PbI2 + CH3COOK
I dried it and mixed it with concentrate KI solution.
2)PbI2 + KI → K [PbI3]
![received_218112553033232.jpeg - 295kB](https://www.sciencemadness.org/whisper/files.php?pid=650488&aid=84999)
[Edited on 4-12-2020 by vano.kavt]
[Edited on 4-12-2020 by vano.kavt]
[Edited on 4-12-2020 by vano.kavt]
[Edited on 4-12-2020 by vano.kavt]
|
|
Lion850
National Hazard
![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif)
Posts: 517
Registered: 7-10-2019
Location: Australia
Member Is Offline
Mood: Great
|
|
Hi Vano very interesting, first time I hear about this compound.
|
|
woelen
Super Administrator
![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif)
Posts: 7998
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
Interesting, this one also is new to me. I know of the mercury variation: HgI2 + 2I(-) --> HgI4(2-), but did not know that PbI2 also has a
iodo-complex. I have made the beautiful bright yellow precipitate of PbI2 many times, but never went so far that I added so much KI, that it
redissolves again.
How do you know that there is not excess KI in your pale yellow compound? My experience with the mercury compound is, that adding a stoichiometric
amount of KI to a suspension of HgI2 in water is not enough to get all of it dissolved easily. You need to add excess KI to get all of it dissolved.
Simply evaporating the solution then is not enough to get pure K2HgI4, you get a mix of K2HgI4 and KI instead.
If you add some of the pale yellow solid to water, does all of it dissolve easily?
|
|
vano
National Hazard
![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif)
Posts: 661
Registered: 22-3-2019
Location: Georgia
Member Is Offline
|
|
Tetraiodomercurates are great compounds. But lead also can produce tetraiodosalts, for example:
K [PbI3] + KI ⇌ K2 [PbI4]
I have never seen it.
|
|
vano
National Hazard
![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif)
Posts: 661
Registered: 22-3-2019
Location: Georgia
Member Is Offline
|
|
Yes it is unstable in dilute solution. It produce lead iodide and potassium iodide.
|
|
vano
National Hazard
![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif)
Posts: 661
Registered: 22-3-2019
Location: Georgia
Member Is Offline
|
|
Quote: Originally posted by woelen ![](images/xpblue/lastpost.gif) | Interesting, this one also is new to me. I know of the mercury variation: HgI2 + 2I(-) --> HgI4(2-), but did not know that PbI2 also has a
iodo-complex. I have made the beautiful bright yellow precipitate of PbI2 many times, but never went so far that I added so much KI, that it
redissolves again.
How do you know that there is not excess KI in your pale yellow compound? My experience with the mercury compound is, that adding a stoichiometric
amount of KI to a suspension of HgI2 in water is not enough to get all of it dissolved easily. You need to add excess KI to get all of it dissolved.
Simply evaporating the solution then is not enough to get pure K2HgI4, you get a mix of K2HgI4 and KI instead.
If you add some of the pale yellow solid to water, does all of it dissolve easily? |
I think it is not excess KI in my pale yellow compound. I read about that in encyclopedia.
|
|
woelen
Super Administrator
![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif)
Posts: 7998
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
Interesting experiment, which I will try myself. I have Pb(NO3)2 and KI, so should be easy for me to try.
|
|
vano
National Hazard
![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif) ![*](images/xpblue/star.gif)
Posts: 661
Registered: 22-3-2019
Location: Georgia
Member Is Offline
|
|
Quote: Originally posted by woelen ![](images/xpblue/lastpost.gif) | Interesting experiment, which I will try myself. I have Pb(NO3)2 and KI, so should be easy for me to try. |
good luck
|
|