The structural flexibility of the antiaromatic 1,4-dihydropyrazine system. The crystal and molecular structure of organometallic derivatives. Journal of Organometallic Chemistry, (296)3:321--337, 1985. [PUMA: antiarom conformation dihydropyrazine dihydropyrazine;crystal dihydropyrazine;mol dihydropyrazine;pyrazine flexibility germyl hydro silyl silyl;structural structure]