Hirhurim recently posted another post about talking in shul. The issue, this time, is whether the sanctity of the synagogue precludes talking in shul even where it would otherwise be permitted to talk. E.g. after davening, or perhaps bein gavra legavra, and so on.
Rabbi Student made reference to a few sources, but two of them I can assemble quite easily from sources already available online. Here is the Aruch haShulchan, siman 151:1-5, and then Igros Moshe, Orach Chaim 1:45.
I do not attempt any translation or summarization here in this post. Perhaps in a later post, it I get around to it.