Summary

Calcium, carbon and oxygen atoms for construction of Calcite ball-and-stick model.
Model sizes (diameters):
Calcium - 21.4 mm; Titanium - 14.7 mm; Oxygen - 13.4 mm;
Holes - 2.1 mm.

Example of final constructed model see on: https://skfb.ly/p9U69

There are 48 Ca-O bonds and 12 Ti-O bonds.
The bond lengths: Ca-O - 37 mm; Ti-O - 28 mm.