RE: I don't know where you get your figure of an average silver particle being 15 nanometers.
A. This was intended as a baseline for metal particles. Though not as a measure for the size of nano-particles accomplished in any given process.
RE: The diameter of a silver ion is 0.252 nanometers ...
A: I think we could proceed with such a figure.
RE: ...Utopia-Silver or Mesosilver, whose particles have been measured to be as small as 0.65 nanometers and below in diameter and which average far less than 15 nanometers in diameter...
A: I think we could also proceed with these figures as well.
RE: thus putting to rest your contention that it is impossible to produce particles that small, since they have done exactly that. 0.65 nanometer is not at all "essentially the same size as a silver atom". A particle with a diameter near the size of 0.65 would actually hold a cluster of several silver atoms.
A: I don't know what just happened here, but it would appear that you are now in agreement with my initial point. That is to say, that silver particles(elemental) cannot be equal-to, or less than the size of a silver ion(see).
With all that being said, it would appear that there was some confusion between the initial statement regarding particle size, and my proposed criticism. Whereas it would now appear(based on your closing paragraph), that you are in agreement with my initial statement.
PS. I can appreciate time constraints, and would like to thank-you for taking the time to follow through on this particular matter.