On the Tetragonal Forms of KMo4O6

A reexamination of the X-ray diffraction data for the tetragonal form of KMo_4O_6 prepared by fused salt electrolysis leads to the conclusion that the crystal structure is better described by using space group P 4/mbm and not P4 as previously reported. However, refinement in the new space group does not result in any significant changes in the atomic arrangement. Possible reasons for the significant difference between the c lattice parameter of this form of KMo_4O_6 and that prepared at high pressures are also discussed.