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In this study, the researchers focused on a MOF called ZIF-8, which consists of a lattice of tetrahedral units made up of a zinc ion attached to four molecules of imidazole, an organic compound.

"Synthetic anion binding is much more challenging because anions can be all kinds of shapes -- spherical, octahedral, even tetrahedral," Gong says.

Circular kite composed of smaller tetrahedral shapes that was built by Bell and his team.

Triangle-based kites had to be arranged in two sections connected by wood—deadweight that tetrahedral designs avoided.

Alexander Graham Bell’s designs for tetrahedral kites, which grew large enough to hold a human aloft.