The paper presents the differential thermal analysis, compared with th
e Ag2HgI4, Cu2HgI4.III, Tl2HgI4, PbHgI4, CdHgI4 combinations electric
conductibility. The results thus obtained lead to the idea of using th
e differential thermal, analysis (DTA) and the electric conductibility
(EC) as the methods for assessing the thermochromic transitions in th
e MXHgI4 type inorganic combinations.