Now I am writing a scientific paper, and I want to write a sentence as follows:
A has a chemical composition so similar to that of B that it also has a high potential.
As you can see, the first 'that' is used to substitute for 'chemical composition', and the second 'that' is used to introduce the following clause.
However, I am so worried because it seems to confusing due to the repetition of 'that'. (Because I am not a native, I cannot make a sentence with assurance...)
So, I tried to use a comma before the second 'that', but I don't know if it will be a correct sentence.