Structurally ferroelectric SrMgF4.

The crystal structure of 0.06% Ce-doped SrMgF4, strontium magnesium tetrafluoride, reported by Ishizawa et al. [(2001), Acta Cryst. C57, 784-786] is shown to satisfy the structural criteria for ferroelectricity and to have a predicted Curie temperature T(c) approximately l450 K. The estimated spontaneous polarization P(s) approximately 11 x 10(-2) C x m(-2) is consistent with classification as a two-dimensional ferroelectric in which minor Delta(x) and major Delta(y), Delta(z) atomic coordinate component displacements are required for ferroelectric switching.