Analogues of two minerals: scottyite BaCu ₂ Si ₂ O ₇ and colinowensite BaCuSi ₂ O ₆ , have been synthesized by hydrothermal method. According to the single crystal X-ray diffraction, synthetic analogue of scottyite is orthorhombic, space group Pnma, a = 6.8805(15), b = 13.190(3), c = 6.8903(17) A; analogue of colinowensite is tetragonal, I4 ₁ /acd, a = 9.9811(2), c = 22.3369(6) A. The high-temperature (HT) X-ray powder diffraction study has shown that both phases are stable within the range of temperature from 26 to 900 °C. Calculated thermal expansion coefficients for scottyite are α _a = = 9 10 ^-6 , α _b = 5 10 ^-6 , α _c = 8 10 ^-6 °C ^-1 at T = 200 °C; α _a = 10 10 ^-6 , α _b = 6 10 ^-6 , α _c = 12 10 ^-6 °C ^-1 at T = 400 °C; α _a = = 10 10 ^-6 , α _b = 8 10 ^-6 , α _c = 16 10 ^-6 °C ^-1 at T = 600 °C, and the main HT deformation of the structure is associated with straightening of chains, built by copper squares, along the c axis. Calculated thermal expansion coefficients for colinowensite are α _a = = 10 10 ^-6 °C ^-1 , α _c = = -5 10 ^-6 °C ^-1 at T = 200 °C; α _a = 9 10 ^-6 °C ^-1 , α _c = 5 10 ^-6 °C ^-1 at T = 400 °C; α _a = 9 10 ^-6 °C ^-1 , α _c = 15 10 ^-6 °C ^-1 at T = 600 °C. The thermal behavior of colinowensite is characterized by contraction of c parameter in the 25-400 °C range of temperature, while in the region 400-900 °C the phase becomes expanded. This high-temperature behavior is interpreted as a stretching of barium polyhedra chains.