To help your readers, may I ask you to shortly explain the concept of optical basicity (I have never heard of that) and to give precise references to those pieces of literature where you found the diverse formulations. This will facilitate finding the formulae.

Hi. It is actually not hard. First you have to convert your analyses into molecular proportion (wt%/molecular weight), then you have to multiply the result by the number of oxygens present in each oxide (2 for SiO2, 1 for K2O, and so on). Sum up everything and reserve the value. Then the same molecular proportion should be multiplied by the optical basicity of the oxide (see Ottonello et al, 2001 for the values of several oxides).

Sum up these and divide for the sum you calculated previously. So... it is Wt%/Mol.Weight x n. of Oxygens x optical basicity of the oxide divided by the sum Wt%/Mol.Weight x n. of Oxygens. It is a bit late, but I just started working with this, sorry...

Hi Adriana Alves, Thanks a lot for your response, I think its never late to learn anything. Here is another thing that I want to ask,  to calculate optical basicity of an individual oxide, moderating parameter is taken into account, which further depends on electronegativity of the metal part of the oxide. In the literature I came across the reports where sometimes electronegativity of metal "atom" is considered and sometimes that of the metal "ion". Can you kindly comment something on that?

 Dear Adriana and Satwinder,

The article "The Influence of Structure on the Physico-chemical Properties of Slags" by Mills (2003) has an appendix which shows how to calculate the Optical Basicity!

Best regards,

Felipe

Hello Kai Fauth,

Slag Basicity is a measure of the acidic-basic character of the oxides, widely used by the glass scientists, slag metallurgists and some geologists as well. You will get the details from the article "A review of optical basicity and its applications to oxidic systems " by John A. Duffy, who is the pioneer of the concept. Recently, we published an article discussing the arguments related to the use of different scales of basicity in " Slag Basicity: What Does It Mean?".

Article A Review of Optical Basicity and Its Applications to Oxidic Systems

https://link.springer.com/chapter/10.1007/978-3-030-05955-2_28

How can we use optical basicity for CaF2 and CaS environment.?

I can able to find out the theoretical values for these two but how can I take number of oxygen atoms present?

It doesn't have oxygen atoms present in it....