Structural phase transitions in Co(II) and Ni(II) phosphate octahydrates in the temperature range 100–300 K

Investigation of structural phase transitions in M3(PO4)2 · 8H2O, where M = Co(II) and Ni(II), was carried out by the method of determining temperature dependence of relative dielectric permittivity, dielectric losses and magnetic susceptibility in the temperature range 100–300 K. This investigation made it possible to establish the fact that both compounds undergo three structural phase transitions each in the mentioned temperature range that have not yet been described in the literature.