I think the closest comprehensive analogical literature source for solid state materials to the aforementioned series like Elsevier's Comprehensive Coordination Chemistry II, Elsevier's Comprehensive Organic Synthesis or Wiliey's Inorganic Syntheses would be Springer's Springer Series in Solid-State Sciences currently consisting of 223 titles:
As shown in figure, if we divide a FCC unit cell into 8 small cubes, then each small cube has 1 Tetrahedral void at its own body centre.
Thus, there are total 8 Tetrahedral voids in one unit cell.
It can also be seen from the figure that the nearest distance between two Tetrahedral voids is a/2.
This picture is from How are the number of tetrahedral voids twice the number of octahedral voids in a CCP structure?:
Let's say the red circles represent a layer of atoms above, and the pink circles a layer of atoms below. The T's and O's represent voids with tetrahedral and octahedral coordination located between layers.
My visualisation: In the image, ...