Around the Cs at fractional (0,0,0), determine separately (a) the closest Cl shell and (b) the closest noncentral Cs shell. Report each distance and population, identify the first-shell coordination polyhedron and its full set of distinct neighbor-neighbor angles about the central Cs, and explain why counting only the two atoms in the displayed primitive cell cannot give either population.

Use the supplied periodic primitive cubic cell, not an isolated XYZ cluster. Cartesian XYZ coordinates are in angstrom; 1 nm=10 angstrom. XYZ atom rows start at one after the two header lines. Fractional positions below are exact; each listed basis atom has occupancy 1. Cell vectors are (a,0,0),(0,a,0),(0,0,a); all angles 90 degrees. Crystal images are r_j+a*(n_x,n_y,n_z) for integer n. No relaxation, defects, thermal motion or finite crystallite envelope is supplied. This primitive cell holds only 2 atoms (Z=1 formula unit), unlike the 8-atom conventional cells used elsewhere in this project. 
CsCl S0011: a=4.12300 angstrom. Row / element / fractional x,y,z:
1 Cs 0 0 0
2 Cl 1/2 1/2 1/2

Search translations n_x,n_y,n_z in {-1,0,1}, excluding the central Cs itself. Treat distinct periodic images as distinct neighbors; use 0.00001 angstrom shell tolerance. Report distances in nm to four decimals and angles in degrees to two decimals.

Attachments:
S0011: item-0002-asset-1.xyz