Crystal structure of ytterbiym formate dihydrate. Morphotropy in the series of Ln(HCOO)3x2H2O

Crystals of Yb(HCOO)3x2H2O and two modifications of (Tm(HCOO)3x2H2O (Tm1) relating to an earlier investigated isostructural series and Tm2) are prepared from formic acid solutions of anhydrous formates X-ray diffraction analysis of Yb(HCOO)3x2H2O is carried out (least square fit in an anisotropic approximation, R=0.081 for 1920 reflections). Three formate groups comprise one bidentate-bridge- and two bidentate cyclic groups. In the crystal the bridge formate groups built up the chains along the [001], joined by the H-bonds into layers. The isostructural nature6f Tm2- and Yb formate dehydrates is established and thus morphotropic trarsition on Tm in the Zn(HCOO)3x2H2O series with Zn=Tb-Yb is observed