Skutterudite structure

Fig. 3. Model of the filled skutterudite structure. The transition metal atoms (Fe, Ru, or Os - small light blue...

Fig. 4. Model of filled skutterudite structure that emphasizes the pnicogen-pnicogen bonding that results in nearly square pnicogen rings. The transition metal atoms (small white spheres) form a simple cubic lattice as shown. The lines connecting the transition metal atoms have been added for clarity and do not correspond to a chemical bond. The only chemical bonds shown in this model are those that form the pnicogen rings. The lanthanide atoms (large dark spheres) occupy the two voids without a pnicogen ring.

Figure 4.50. Crystal structures of an unfilled lrSb3 skutterudite (top - Sb atoms shown in black) and Type I/Type II clathrates (bottom). In the skutterudite structure, a void is present in the center of the unit cell, surrounded by 12 Sb atoms. For the clathrate structures, tetrahedrally bound framework atoms (e.g., Ge, Sn, Si) are illustrated in blue, and guest atoms within the various cages are shown in orange and pink. Reproduced with permission from (i) Nolas, G. S. Poon, J. Kanatzidis, M. MRS Bull. 2006, 31, 199, Copyright 2006 Materials Research Society and (ii) Chem. Mater. 2000, 12, 697. Copyright 2000 American Chemical Society.

The skutterudite structure is related in a rather simple way to the Re03 structure. The non-metal atoms in the Re03 structure situated on four parallel edges of the unit cell are displaced into the cell to form a square group, as shown for two adjacent cells in Fig. 6.20(a). From the directions in which the various sets... 

The diffraction patterns of the IrSbs reacted material taken from the two different regions were identical to each other as shown in Fig.2, and they agreed with the pattern of a skutterudite structure. It is confirmed that a homogenous skutterudite IrSb3 structure was formed by the liquid-solid phase sintering of Ir and Sb powder mixture. 

Fig. 3. Model of the filled skutterudite structure. The transition metal atoms (Fe, Ru, or Os - small light blue spheres) are at the center of distorted octahedra formed by the pnicogen atoms (P, As, Sb - green spheres). The lanthanide atoms (red spheres) are located at the center of a cage formed by 12 pnicogen atoms. The skut-terudile structure results if the lanthanide atoms are removed fiom the structure and the transition metals (Fe, Ru or Os) are replaced by transition metals with one more outer shell electron (Co, Rh or Ir).

Loevvik OM, Prytz O (2004) Density-functional band-structure calculations for La-, Y- and Sc-filled CoP3-based skutterudite structures. Phys Rev B 70 195119/1-195119/6... 

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