The caesium oxygen interactions in the crystalline solids

Through the study of the Cs–O bonds registered in the literature one observes that: (i) the bond lengths range from 2.46 to 3.60 Å; (ii) the preferential coordination numbers adopted by the caesium ions are 8, 9 and 10 but values from 1 to 12 also exist; (iii) the average bond lengths increase with the coordination (CN) of the caesium ions with the following values: 2.714 Å (CN=1), 2.98 Å (CN=2), 3.057 Å (CN=3), 3.104 Å (CN=4), 3.149 Å (CN=5), 3.188 Å (CN=6), 3.224 Å (CN=7), 3.245 Å (CN=8), 3.261 Å (CN=9), 3.269 Å (CN=10), 3.293 Å (CN=11) and 3.323 Å (CN=12). A new Rij=2.469 constant is determined with all the caesium coordination polyhedra to compute electrostatic bond valence sums. The Ueq values of caesium in crystal structure are about 0.03 and generally less than 0.06 similar to those of the oxygen atoms and often bigger.