Va. Blatov et al., Analysis of the environment of beryllium, magnesium and alkaline earth atoms in oxygen-containing compounds, ACT CRYST B, 55, 1999, pp. 139-146
About 2100 inorganic and organometallic compounds containing beryllium, mag
nesium and alkaline earth atoms (M) were investigated with Voronoi-Dirichle
t polyhedra (VDPs). It is shown that the coordination numbers (CNs) of the
M atoms in MOn coordination polyhedra can be determined by means of VDPs wi
thout crystal-chemical radii. The distributions of the M-O distances in the
coordination spheres of the M atoms are bimodal for M = Be or Mg and monom
odal for the other alkaline earth metals. Beryllium and magnesium coordinat
ion polyhedra containing weak M-O contacts were classified by variants of t
heir distortions. It is found that the volume of the domains of the Mg, Ca,
Sr and Ba atoms is independent of their CNs at CN greater than or equal to
6 (up to 16 for barium). The possibility of using the model of deformable
spheres to describe the crystal structure of the compounds investigated is
suggested.