The isobaric heat capacity of double thulium tellurites is studied via dynamic calorimetry in the range of 298.15–673 K. It is used as the basis for deriving the equation C p o ∼ f(T) and determining the thermodynamic functions. Dependences C p o ∼ f(T) are found to have second-order phase λ-transitions.

The isobaric heat capacity of double magnesium tellurite is studied in the range of 298.15-673 K and used as a basis for deriving dependences C-p(o)similar to f(T) and determining their thermodynamic functions. Dependences C-p(o)similar to f (T) are found to have abnormally sharp lambda-like peaks, due probably to second-order phase transitions.

A possibility of solid-phase synthesis of new cerium double tellurites with s -elements from the oxides of cerium(IV), tellurium(IV) and magnesium (calcium, strontium) carbonates was demonstrated. It was determined by the X-ray diffraction method that the magnesium-cerium tellurite crystallizes in a cubic system, while calcium-cerium and strontium-cerium tellurites crystallize in the tetragonal crystal system.The temperature dependence of the electrical resistance of these compounds in the range of 300–600 K was measured. The plots include sharp anomalous jumps due probably to the phase transitions of type II.

This article demonstrates the possibility of obtaining of new double tellurites of cerium with s-elements from dioxides of cerium, tellurium and carbonates of magnesium (calcium and strontium) by solid-phase method. It was determined by X-ray-phase analysis that tellurite of magnesium-cerium crystallizes in cube, and tellurites of calcium-cerium and strontium-cerium crystallize in tetragonal singony correspondingly. The parameters of their elementary cell, X-ray and picnometric density have been determined as well. The temperature-dependence of electrical-resistance of these compounds has been studied at the temperature range 300-600 K. Sudden changes which are likely connected with the 2nd type phase transitions have been observed on dependence-curves.

Models of geometrical structure of new double zinc and cadmium tellurites with s- elements on the basis of quant- chemical calculations on length of communication and valent corner in structures of investigated connections were offered.

Double zinc and cadmium tellurites with s- elements have been synthesised for the first time from oxides of tellurium ( IV), zinc, cadmium and carbonates of s- elements by solid- phase method. Types of singony, parametres of connection unit cell, roentgen and picknometric densities were determined by the method of X- ray analysis.