Metal-rich suboxides

The molar volumes of the metal-rich suboxides are nearly equal to the sum of the cluster volumes taken from the compounds Rb902 and CS11O3 (396 and 573.5 cm mol , respectively) and the atomic volumes of the additional metal taken from the... 

The more metal rich suboxides may be interpreted as intermetallic phases of the duster metals [Rb902] and [C nOj] with excess Rb and Cs, [4] as in [Rb902]Rbj, [Cs 03]Cs,o, and [Csu03]C. The molar volumes of these phases closely correspond to the sum of the molar volumes of Rl>902 or Csi]03 and the atomic volumes of Rb and Cs respectively. To take an example, the molar volumes of Cs 03Cs and Cs,i03Cs,o exceed the molar volume of Csn03 by 69.9 and 696.5 cm mol" respectively, and can be compared with the 69.4 cm mol volume of elemental Cs at 223 K. Qearly, the Cs atoms in these suboxides form purely metallic bonds to the [Cs 03] cluster. 

In the metal-rich suboxides the metal is concentrated in purely metallic regions. In Fig. 4.8, a scheme of the structure of the phase Rb60 is reproduced. There the Rb902 clusters are arranged in layers that alternate with others of metallic rubidium atoms. In the case of the CS7O as illustrated in Fig. 4.9 the CS11O3 clusters are arranged to form columns which are in turn surrounded by purely metallic cesium atoms. 

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