Crystal frames problem, what actually asking?

[frostysh]

Homework Statement

The problem from Sterway, Jewett book.

The Attempt at a Solution

The answer in the book is something like 0,141 nm, as I remembered but I cannot achieve such answer coz' I cannot understand what actually asking, d is looks like a distance between two centers of the atomic spheres, but I don't think that it can be 0,141 nm, probably due to my English language, so can somebody clarify for little bit, what the hell I need to find in this problem. I am stucked for now, and my brain will start to melt soon. And imho - this book have too much of unnecessary problem, 70 problem for the first chapter is too much... Thanx.

 

[BvU]

In the same way as the distance between vertical or horizontal planes is L, the distance between the 45 degree planes is ${1\over 2}\sqrt 2$ L. Easiest seen in a side view:

 

[frostysh]

In the same way as the distance between vertical or horizontal planes is L, the distance between the 45 degree planes is ${1\over 2}\sqrt 2$ L. Easiest seen in a side view:
View attachment 198771

Or this picture in the book is distracting, or frostysh is just too dull :), anyway I have solved the problem on my new cool self-made school-board, and now I am very happy ^^. Thanx again, Solved.