Crystal growth experiments in the systems Ni 2 M SbO 6 ( M = Sc, In) using chemical vapour transport reactions: Ni 2 InSbO 6 and NiSb 2 O 6 crystals in the millimetre range

Endothermic chemical vapour transport (CVT) reactions of Ni 2 M SbO 6 ( M = Sc, In), using a temperature gradient T ¯ of 1313 → 1233 K and HgCl 2 , HgBr 2 , PtCl 2 or TeCl 4 as transport agents, led to growth of Ni 2 InSbO 6 single crystals in the millimetre range, whereas in the case of Ni 2 ScSbO 6 an incongruent dissolution of the solid in the source region was observed, leading to the formation of single crystals of the ternary phase NiSb 2 O 6 in the sink region. The crystal structures of the obtained crystals were refined from single crystal X‐ray data with high precision [Ni 2 InSbO 6 : R 3, Z = 3, a = 5.21640(10) Å, c = 14.0142(3) Å, 1279 structure factors, 33 parameters, R [ F 2 > 2 σ ( F 2 )] = 0.0189; NiSb 2 O 6 : P 4 2 / mnm, Z = 2, a = 4.63910(10) Å, c = 9.2182(2) Å, 500 structure factors, 19 parameters, R [ F 2 > 2 σ ( F 2 )] = 0.0145]. Ni 2 InSbO 6 crystallizes in a corundum‐related structure, NiSb 2 O 6 in the trirutile structure type. Spontaneous polarization and the ferroelectric transition temperature were estimated from the atomic arrangement and cation displacement along the polar axis in Ni 2 InSbO 6 . Magnetic measurements on Ni 2 InSbO 6 evidence an antiferromagnetic transition near T N = 74 K, with significant magnetic frustration.