The cover shows the crystal structure of the alanate NaAlH 4 , a new class of hydrogen storage material. Al atoms are red, Na atoms are green, and H atoms are blue. In this class of materials, hydrogen "encapsulates" Al to form a hydrogen-rich anion, AlH 4-, whose structure resembles that of methane, CH 4. The alanate structure differs from that of the metal hydrides like MgH 2 , where hydrogen is encapsulated by metal ions, and the hydrogen density is correspondingly lower. In the cover image, the diameter of the hydrogen atoms is enlarged to reflect the very high scattering cross section of neutrons for hydrogen and deuterium. This high sensitivity makes neutron scattering a natural tool for probing the interaction of hydrogen with materials. (In the report, see the sidebar, Using Neutrons to "See" Hydrogen, on page 38).
ChemInform Abstract The new title superconductor (space group Pnma, Z=4) is prepared in the same way as the recently prepared isostructural Br salt by electrocrystallization. The chloride salt has band dispersion relations and a Fermi surface practically identical with those of the bromide salt.
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