Bacillus pumilus SAFR-032: A model for planetary protection

A silicon clathrate compound of the following composition:(Li4)xAe6Si46wherein (Li4) represents a Li4 cluster; Ae is an alkaline earth metal element selected from the group consisting of Ba, Sr and Ca; and x is the number ratio of the Li4 complex to the other elements and 0structural units of crystals, Si46 clusters, each of which consists of Si20 clusters and Si24 clusters with cage structures formed by silicon atoms as the framework of the crystal and at least part of said Si24 clusters encapsulate alkaline earth metal atoms inside the cage, and at least part of the Si20 clusters encapsulate Li4 inside the cage.