Exactly 20 years have passed since the surprising discovery of the first quasicrystal by Shechtman [1]. Centuries of prior research in crystallography had led to the development of a beautiful and well-established science of crystals [2]. Modern crystallography was born in the 17 th century thanks to the brilliant idea – – attributed to such great scientists as Kepler and Hooke– –that the obser...

Reactions of equemolar amounts of lead (II) nitrate and 2,2'- bipyridine o r l , 10- phenanthroline in aqueous methanolicsolution yield crystals of Pb (bipy)(H O)(NO ) (1) or Pb (phen) (H O) (NO ) (2) respectively. Their structures were determined by X-ray crystallography. The method and structure determination is described