  Antiferromagnetic PbMnTeO6, also known as mineral kuranakhite, has been
reported recently to have all three cations in trigonal prismatic coordination,
which is extremely unusual for both Mn(4+) and Te(6+). In this work, the phase
was reproduced with the same lattice parameters and N\'eel temperature TN = 20
K. However, powder neutron diffraction unambiguously determined octahedral
(trigonal antiprismatic) coordination for all cations within the chiral space
group P312. The same symmetry was proposed for SrMnTeO6 and PbGeTeO6, instead
of the reported space groups P-62m and P31m, respectively. PbMnTeO6 was found
to be a robust antiferromagnet with an assumingly substantial scale of exchange
interactions since the Neel temperature did not show any changes in external
magnetic fields up to 7 T. The determined effective magnetic moment meff = 3.78
mB was in excellent agreement with the numerical estimation using the effective
g-factor g = 1.95 directly measured here by electron spin resonance (ESR). Both
specific heat and ESR data indicated the two-dimensional character of magnetism
in the compound under study. The combination of chirality with magnetic order
makes PbMnTeO6 a promising material with possible multiferroic properties.
