Observable as tetra- +‎ pylon. tetrapylon (plural tetrapyla) (architecture) A Roman-style cubic structure with a gate on each of its four sides. Translations GeSe. It exists as black crystalline ...

Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland ...

Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, Aachen, 52074, Germany ...