The Structural Model of Keggin and Miles

The imit cell shown in Fig. 1 is of the cubic face-centered t5q e and has a cell edge of about 10 A. This cell maybe thought of as divided into eight small cubes which will hereafter be referred to as octants. According to 

According to this description, the basic feature of the structure is a three-dimensional connection of M Ce and M- Ne octahedra. Whereas aU the ions M are in a weU defined coordination environment, the unit cell contains two different kinds of metal ions M-.  

The ions of the first kind are in the octahedral nitrogen holes (position 4 a) of the pol5nneric framework, whereas the ions of the second kind are assumed to be present as uncoordinated interstitial ions at the centers of the eight small cubes. Due to the postulated random distribution of 

For the four most frequently realized stoichiometries of Prussian blue analogs M [M (CN)6]i rHaO the model of K gin and Miles postulates the structural properties summarized in Table 1. 

---