Marshall <[email protected]> wrote: > >On 9/15/2011 11:56 PM, Mike Monett wrote: >> Marshall, I would really like for you to do the thermal >> decomposition experiment for silver hydroxide. It is one of the >> easiest of all to perform, since it occurs at such a low temperature >> - barely enough to cook hamburger, if you can wait that long:) >> >> But there is something magic when you see the black deposit turn >> gray right in front of your eyes. It reaches somewhere deep down >> inside and you suddenly realize that what these people are saying >> could actually harm you. So you begin to wonder what other mistakes >> they have made, and what is the real truth about what is happening. >> >I am not questioning that you have seen the effect. I am however >questioning your interpretation of it. First I cannot find any >reference anywhere to silver hydroxide. It is not even in my CRC >handbook, and every reference I can find says that it can only exist in >a hydrated form. Thus I am unable to find anywhere that tells its color, >if it does exist. You are claiming that the black stuff is silver >hydroxide, I think it is silver oxide Ag2O, which my book says is black >or brown-black. The crystalline form shifts when it is heated. Silver >oxide is normal a cubic crystal, but when deposited on an electrode I >would expect most of it to be amorphous. If it is amorphous, it would >almost certainly be black. As is normal with amorphous materials that >are normally crystalline, they will form crystals when they are heated >sufficiently. So that goes right along with the idea that a black >amorphous compound crystallizes and changes color when heated. > >Is there any test data to support either of these possibilities. In fact >there is. There is a paper that shows that when formed by an >electrolytic cell and deposited on an electrode, Ag2O is indeed laid >down as a mixture of amorphous and cubic forms. This can be viewed at >http://web.mit.edu/dsadoway/www/134.pdf > >I am unable to find at what temperature you said this action takes >place. Another possibility is that the precipitate contains both AgO >and Ag2O. AgO decomposes at about 100 C lower temperature than Ag2O. >This is given in the paper at >http://www.iupac.org/publications/pac/2/1/0211/pdf/ which also shows >that various forms of Ag2O, specifically the the 220 and 331, >spontaneously form the cubic 111 form at temperatures no higher than 150 >C, which is the temperature they did the annealing at. > >Marshall
1. In your 134.pdf, sodium acetate and AgNO3 have nothing to do with silver ions combining with hydroxide ions in the Nenst Diffusion layer in distilled water and forming AgOH. 2. Ag2O decomposes at 280C. If AgO decomposed 100C lower, it would still be 180C. 3. AgOH decomposes between 60C to 80C. That is lower than any other compound of silver, and 100C lower than AgO. 4. If AgOH were soluble, or if it changed spontaneously to Ag2O, you would never see yellow cs. Everything would be ions, which are not visible to the eye. 5. If the material that forms on the elecrodes were Ag2O, it would dissolve. You would never see the black deposit. 6. What other compound of silver meets all of the above? Only AgOH. Mike -- The Silver List is a moderated forum for discussing Colloidal Silver. Rules and Instructions: http://www.silverlist.org Unsubscribe: <mailto:[email protected]?subject=unsubscribe> Archives: http://www.mail-archive.com/[email protected]/maillist.html Off-Topic discussions: <mailto:[email protected]> List Owner: Mike Devour <mailto:[email protected]>
