Darstellung,Kristallstruktur und IR‐Spektren von BeSeO3 · H2O – Wasserstoffbrücken und Korrelation von IR‐ und Strukturdaten in den Monohydraten MSeO3 · H2O (M = Be,Ca, Mn,Co, Ni,Zn, Cd)

Preparation, Crystal Structure and IR Spectra of BeSeO₃ · H₂O – Hydrogen Bonds and Correlation of IR and Structure Data in the Monohydrates MSeO₃ · H₂O (M = Be, Ca, Mn, Co, Ni, Zn, Cd) BeSeO₃ · H₂O (oP32) has been obtained by treating amorphous BeSeO₃ · 4 H₂O precipitated from Be(HSeO₃)₂ solutions hydrothermally at 150 °C. The crystal structure (P2₁2₁2₁, a = 560.59(4), b = 755.25(5), c = 781.14(5) pm, Z = 4, D_X = 3.092 gcm^–3, R = 0.018 for the 2034 reflections with I > 2σ_I of the enantiomer investigated) contains BeO₃(H₂O) tetrahedra built up from three selenite and one water oxygen atoms. The BeO₃(H₂O) tetrahedra are 3 D‐connected via Se atoms of trigonal pyramidal SeO₃^2– ions. The Be–O distances are 161.8 to 164.4 pm. The Se–O bond lenghts (169.2–170.3 pm) and the O–Se–O bond angles (98.1–101.4°) are normal. The water molecules of crystallization form together with the SeO₃^2– ions screw‐like hydrogen bond systems along 100]. Despite the strong synergetic effect of the Be²⁺ ions, the hydrogen bonds (d(OH…O) = 267.4 and 276.4 pm, respectively; ν_OD of matrix isolated HDO molecules: 2244 and 2405 cm^–1, respectively) are normal compared to other neutral selenite hydrates. Together with the hitherto known monohydrates M^IISeO₃ · H₂O and other beryllium salt hydrates, the hydrogen bonds of BeSeO₃ · H₂O are discussed with regard to their geometry and IR spectroscopy.