Bravais lattices materials having

In positronium forming materials without optical phonons much longer Ps slowing-down times should be found. This may be tested by AMOC measurements in solid rare gases, crystallizing in the face centered cubic (fee) structure which, being a Bravais lattice, does not have optical phonon branches. 

The recent discoveries of an efficient synthesis [1] of Cfto and superconductivity in K3C60 and Rb3C6o [2] have generated great interest in the structural and electronic properties of these materials. It is known that at room temperature C o molecules are centered at fee Bravais lattice sites in both solid Cm and K3C60 (3l. Recently it was reported [4] that solid Cm undergoes a structural phase transition around 250 K from fee to the simple cubic Pa3 structure at low temperature. Both x-ray and NMR measurements [3] indicate that this transition is related to the orientational order of the Cm molecules. 

The most common form of crystalline alumina is corundum, which has a rhombohedral Bravais lattice with a space group R-3c. These materials have been used in energy storage, alkali metal thermal-to-electric conversion cells, and gas sensors. In recent years, it has been reported that alumina can also reduce heat, humidity, light, ozone and gamma radiation, flame resistance, and the crack growth in NR. ... 

The crystal structures of all extended solids are comprised of a Bravais lattice, which is a periodic arrangement of points in space, and a basis, which is the atom or atoms associated with each lattice point [1]. While a single-atom basis is sufficient for some crystal structures, including body-centered cubic (BCC) or face-centered cubic (FCC), many materials have multiple-atom bases. Most semiconductors, including those illustrated in Fig. 1, fall into the latter class of materials and are briefly summarized below. The structure of bulk crystals are described here, but note that synthesis method or nanoscale confinement can yield alternatives [4—6]. 

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