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.

Graphical abstractA survey of more than 1000 of oxygen polyhedrons around caesium ions shows bond lengths ranging from 2.46 to 3.60 Å with 32% of the shortest bonds in the polyhedrons less than 3.00 Å. Coordination numbers from 1 to 12 are observed, in which the average bond lengths increase from 2.714 to 3.323 Å with the coordination, and with a preference for 8, 9 and 10-fold surrounding.Figure optionsDownload full-size imageDownload as PowerPoint slide