[Big-Daddy]

Could someone explain the parameters of the Pitzer equation to me?

So far, I have a version of the equation (found here: http://www.cord.edu/faculty/ulnessd/legacy/fall06/prerna/prerna.pdf), it is the second half of the right-hand side I cannot understand - in the first half, most of the terms are clear (e.g. z is the integer charge on the ion for which this is the activity equation), but on the second half I understand nothing. I can suppose that the summation means that these terms will be operated for each ion - that's fine, but what do the terms mean? B(i,j)m_j means what? And what quantities would I need to know to calculate it?

Thanks for any help.

[Borek]

If memory serves me well B_i,j is an experimentally determined coefficient specific for i^th and j^th ion interaction. m_j is the molality of j^th ion.

Good luck finding these coefficients. You will need it.

[Big-Daddy]

If memory serves me well B_i,j is an experimentally determined coefficient specific for i^th and j^th ion interaction. m_j is the molality of j^th ion.

Good luck finding these coefficients. You will need it.

Ah I see, they are that specific! This explains why we aren't taught this stuff. If B_i,j is determined experimentally for a given couple of ions then there is no point in trying to find a general method applicable to all such cases, so I'll go with the extended Debye-Huckel equation instead for activity effects.