Weblink 9.2 The structure of solid Rb₂O and Cs₂O

Metal ions are shown grey and the oxygen ions in red. Rb₂O has the anti-fluorite structure in which each O²⁻ ion is coordinated to eight Rb⁺ ions, and each Rb⁺ ion is coordinated to four O²⁻ ions; the green cube picks out the unit cell in this structure.

Cs₂O adopts the anti-cadmium iodide structure in which each O²⁻ ion is coordinated to six Cs⁺ ions, and each Cs⁺ ion is coordinated to just three O²⁻ ions.

• Click and drag to rotate the structure; hold down shift, then click and drag to zoom.
• Use the drop-down menu to select Rb₂O or Cs₂O
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