Synthesis, Crystal Structure and Thermal Behavior of Gadolinium Dicyanamide Dihydrate Gd[N(CN)₂]₃ · 2 H₂O

Gadolinium dicyanamide dihydrate Gd[N(CN) 2 ] 3 · 2 H 2 O was prepared by ion exchange in aqueous solution followed by evaporation of the solvent at room temperature. Gd[N(CN) 2 ] 3 · 2 H 2 O was characterized by single‐crystal structure analysis, FTIR spectroscopy and DSC analysis. In the crystal there are three crystallographically independent [N(CN) 2 ] − ions and Gd 3+ which are coordinated by six N atoms from six different [N(CN) 2 ] − ions and two O atoms from two water molecules forming an irregular quadratic antiprism. Four H bonds have been identified in the structure of Gd[N(CN) 2 ] 3 · 2 H 2 O, two of them running to terminal N atoms and two to the bridging N atoms of dicyanamide ions (Gd[N(CN) 2 ] 3 · 2 H 2 O: P 2 1 / n (no. 14), a = 7.4845(15) Å, b = 11.529(2) Å, c = 13.941(3) Å, β = 93.98(3)°, Z = 4, 1948 reflections, 175 parameters, R 1 = 0.0493). The DSC analysis indicates that Gd[N(CN) 2 ] 3 · 2 H 2 O looses the crystal water at temperatures around 130 – 140 °C forming anhydrous Gd[N(CN) 2 ] 3 , the structure of which has been refined by the Rietveld method based on X‐ray powder diffraction data. Gd[N(CN) 2 ] 3 was found to be isotypic with Ln[N(CN) 2 ] 3 (Ln = La, Ce, Pr, Nd, Sm and Eu) which previously have been described in the literature.