Hi Ivan, I concur with you on these issues, though I feel that my opinion is only marginally qualified. I am getting a sense that the net effect of attractive and repulsive forces are a function of particle proximity, which is a function of concentration and particle size---when originally separated from the electrode. Among many other factors, of course.
I think we need to give careful attention to noting if the dimension is given as diameter or radius. I think I may have compared one with the other at various times. Those simple little details give you a 100% error in a blink. What does Brooks Bradley know that causes him to prefer 5 PPM? Has anyone ever asked? Brooks, if you see this, please comment. If ions come off the electrode, how do they get together in larger groups if they all have a + charge? If an ion already has a + charge, as a valence, then what is the effect of the electron which gives a cluster a + charge on a group of neutral atoms? A +2 charge? Ah, to spend a day with a very experienced electrochemist... I am going to get a flick of my silver bits as soon as I can get the process a little more standardized and a wad of FRNs to pay for the scope. Probably sometime this century. James Osbourne, Holmes [email protected] -----Original Message----- From: Ivan Anderson [SMTP:[email protected]] Sent: Saturday, August 28, 1999 10:57 PM To: [email protected] Subject: Re: CS>Ion size was buying CS ----- Original Message ----- From: James Osbourne, Holmes <[email protected]> To: <[email protected]> Sent: Sunday, 29 August 1999 07:16 Subject: RE: CS>buying CS > Covalent radius is still larger than 1.26 A., at 1.34. If the size is > 1.26, that could be one atom only of ionic silver; not a cluster of > atoms with a charge---regardless of the consequences of that. And, 1.26 > may be smaller than one silver ion. I use web elements for reference: http://www.webelements.com/ who note that the covalent radius is 153 pm (1.53 A). Yes, silver ions (Pauling radius of silver ion 1.26 A). The electrophoretic method may be a better way to determine particle size, due to the fact that samples for electron microscopy must be dried before scanning, which possibly leads to changes in particle structure. The electrophoretic method measures the speed of particles under the influence of a potential in a liquid medium (water). Then applies some equations, to calculate the effective radius of the particle. The size of the silver ion is found to have a radius of 0.145nm (1.45 A) by this method. > When I made sol with 3 9V batts, a lot of it fell out of solution, so some > of it must be quite a bit larger than 1.26 A. There's the rub, whilst silver leaves the anode and enters the sol as single ions, how long they stay discrete and in what form they ultimately find equalibrium depends on the configuration of the generating parameters. These are the very variables we struggle with daily on the list. It can be assumed (in my opinion) however, that few if any silver sols contain single ions but rather particles of two or more ions. Of course there are other particles which may enter the sol via the cathode build up. > I want to see a picture of the stuff with a nm scale in it. Does anyone > have one? I think there will be a wide range of sizes present; and that > could be a good thing. You're not going to get one are you ;-) > James Osbourne, Holmes Ivan -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]> -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
