Good stuff Ivan... Could you direct me to basic info on "The electrophoretic method may be a better way to determine particle size,..." I have seen the term but cannot recall how it works. How does the price compare with TEMs?---tests, of course, not the instrument.
Also, Bob Berger said that one method of determining particle size is to measure absorption in the UV range with a Spectrophotometer. Are you familiar with that technique? If I can get TEM pix of my size, I might be able to correlate that with UV Spec. readings in some rough sort of way...enough to verify that I am producing a good sol. Perhaps. Of course that means buying a new tube and filter for the old Spectronics 20. Sometimes I think it would be easier to have a non-antibiotic drug habit... 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]>
