Study on the System CoSeO 4 NiSeO 4 H 2 O at 30°C Crystal Structure of CoSeO 4 · 5 H 2 O

A study of the system CoSeO 4 NiSeO 4 H 2 O at 30°C has been carried out. Crystals were obtained by slow evaporation from a water solution. The identified phases were CoSeO 4 · 5 H 2 O and NiSeO 4 · 6 H 2 O, but CoSeO 4 · 6 H 2 O is identified when the crystallization of Co compound is carried out in presence of Ni. The three phases show a limited replacement of metal according to X‐ray powder results. The crystal structure of CoSeO 4 · 5 H 2 O has been solved, the come pound is triclinic, a = 6.435(1), b = 10.703(2), c = 6.220(1) Å, α = 98.71(1), β = 109.60(2), γ = 75.54(1)°, P 1 , Z = 2. Refinement was terminated at R = 0.035 for all observed reflections. The crystal structure is isostructural to CuSO 4 · 5 H 2 O and consists of Co(H 2 O) 4 ions chains parallel to [1 1 0] μ‐linked by the SeO 4 . The fifth water molecule acts as buffer.