I already have determined interplane distances and corresponded crystallographic directions for the b-FeSi2. I'm interesting in b-FeSi2 [010] or [001] direction which is in the line with Si [111] one as can be seen on FFT images (b). So, I'll be very grateful for the help with correct writing of the relationship. Current version is: b-FeSi2 [010] or [001] // Si [111]; b-FeSi2 (101) or (110) // Si (111) but I'm not an expert in crystallography and indexing.