Citation stating the maximum conductivity or resistivity of water

Hi

Over the past week the has been so excellent feedback(threads) on my question of water conductivity. In a few thread the value of 18.3MR (0.055uS) was mentioned, forgive me for being pedantic but could somebody help by quoting a reference that cites this figure (either in ohms, mhos or Siemens)?

Cheers

Wayne

Hi Can anyone send me a pdf of a paper (recent) to mail-nospam-@wlawson. Remove -nospam-

Thanks again

That's only at 25 deg C... in fact the actual value is both temperature and pressure dependent.

Some relevant references:

Eigen, M. & de Maeyer, L. (1955) Untersuchungen über die Kinetik der Neutralisation I. Z. Elektrochem. 59 986.

Geissler, P. L.; Dellago, C.; Chandler, D.; Hutter, J. & Parrinello, M. (2001) Autoionization in liquid water. Science 291 2121-2124.

Stillinger, F. H. (1975) Adv. Chem. Phys. 31 1.

Rapaport, D. C. (1983) Mol. Phys. 50 1151. Chen, S.-H. & Teixeira, J. (1986) Adv. Chem. Phys 64 1.

Tim.

Wouldn't it be easier for the reader if there was *one* such thread rather than you starting a new one every few days?

You still aren't specifying a temperature or a pressure. s long as fail to do that you will be unable to make use of any answer you get.

Also, it has been explained to you that for your stated application ultrapure water would be a very poor choice and would give you a different reading every time you ran the experiment. Ultrapure water with no dissolved gasses is one of the *least* likely things that you might find as a contaminant of standard electrical equipment. Pick another liquid. This is good advice. I strongly suggest that you not ignore it.

That being said, here are your references. It would be a Good Thing if you were to use them wisely:

Why you shouldn't ask for E-mail responses on Usenet:

Hi

I am writting a paper and it is fround upon to include web address or usenet ref. It need it to be a printed publication.

Wayne

[reaches up to book shelf above desk, aha!] Yes: Aylward & Finlay, "SI Chemical Data", p. 125 in the 2nd Ed., under Ionic Properties of Water. Note the SI units though, m, not cm.

I suspect the CRC "rubber bible" would also have it, but I have only some rather old editions on the shelf.

--
Dieter Britz,   Kemisk Institut, Aarhus Universitet, Danmark.

In giving you the Aylward & Finlay reference, I didn't mention that it provides figures for a number of temperatures. It should be an easily accessible book, even in your apparently church-mousy situation.

Good luck with the paper. When you write it, make sure you turn spell- checking ON...

--
Dieter Britz,   Kemisk Institut, Aarhus Universitet, Danmark.

The fact that you are writing a paper and that papers require references is irrelevant. The fact remains that the basic assumption behind your paper (that ultrapure water with no dissolved gasses is something that one is likely to find as a contaminant of standard electrical equipment) is flawed.

I suggest that you write a paper analysing what happens when boysenberry jam contaminates electrical equipment. That would be far more likely, and the jam would stay jam long enough for you to take a resistivity measurement.

You seem determined to ignore the above advice. Care to tell us why?

Vested interest. Whilst I believe in the freedom of information the people who pay for my research would like to be the first to know about it. Thus one should not bite the hand that feed you. I guess you may call it a balancing act. I will share as much as I feel I can. Thanks for you help.

Cheers

Wayne

Nonresponsive answer noted. I still have no idea why you seem determined to ignore the above advice.

I call writing a paper about contaminants in electrical equipment that assumes a contaminant (gas-free ultrapure water) that will never, ever be found in any electrical equipment to be quite a good example of biting the hand that feeds you. But, if you insist on screwing your customer with a bad analysis, who am I to stand in your way?

Followups set. I am not interested in further discussion.

Correct; the CRC is stating the *SI* units. BUT. In the trade, the commonly used terminology (like i said) is

*megohms*.

Sure. I just pointed that out, not as a criticism of your "Megohms" but to avoid Wayne's getting confused by the figure in Aylward & FInlay, of 5.5, rather than 0.055. The units for 5.5 are microS/m, and the resistivity figure of 18.3 must be MOhm.cm. If Wayne is writing a paper, he must be more pedantic than trade jargon.

--
Dieter Britz,   Kemisk Institut, Aarhus Universitet, Danmark.

Check.