Metal–organic frameworks (MOFs) are composed of metal nodes connected by organic linkers. With the massive amount of possible metal and linker combinations, it is critical to develop structure-property relationships. However,...

1007mesons and the nucleons to survive longer than the electrons, hence to arrive in the lower atmosphere accompanied by ionizing particles with extremely low densities. On the other hand, evidence has been found 7 that an appreciable fraction of the penetrating showers do not contain any electro-magnetic radiation. If this kind of process is possible at high energies, part of the penetrating component could be created without the accompanying electrons of the extensive showers.Support for the hypothesis that all particles observed in the lower atmosphere are generated in extensive showers, is provided by the facts that, whenever three or more coherent penetrating particles coming from the air have been recorded, an extensive shower accompanying them has been recorded too; and that the probability of recording an extensive shower accompanying the iV-component increases when the energy of the iV-component increases. 8 1 We disregard here the tail of primary radiation which may cross the atmosphere without interacting with any nucleus of the air.2 B. Rossi, Rev. Mod.