Phase relations in the Zn2V2O7-Cu2V2O7 system from room temperature to melting

High-Temperature Heat Capacity of Zn2V2O7–Cu2V2O7 Solid Solutions

“…It can be noted that all vanadates synthesized in this work have space group C2/c at room temperature (at low temperatures, Cu 2 V 2 O 7 is characterized by space group Fdd2 [8]), and the unit cell parameters in the Zn 2 V 2 O 7 -Cu 2 V 2 O 7 system are changed as follows: a and V increase, b ans β decrease, and c is changed complicatedly. Similar tendency of to changes in the unit cell parameters in this system was also observed at temperatures 823 and 903 K [9].…”

“…According to [9], no new intermediate compounds form in the Zn 2 V 2 O 7 -Cu 2 V 2 O 7 system, and the phase proportions are determined by the structural transformations in the solid solutions based on the crystal structures of various modifications of Zn 2 V 2 O 7 and Cu 2 V 2 O 7 . According to [6], at room temperature, the α-Zn 2 V 2 O 7 structure exists at the contents of Cu 2 V 2 O 7 from 2.5 to 30 mol %, whereas the region of homogeneity of the β-Cu 2 V 2 O 7 -based solid solution extends from 35 to 92.5 mol % Cu 2 V 2 O 7 .…”

“…It is seen that dependence C p = f(T) has a clear extreme with the maximum value at temperature T max = 840.8 K. In the heating and cooling curves of Zn 2 V 2 O 7 measured by the differential thermal analysis method, we detected the existence of a reversible effect, the temperature of which coincides with the maximum in C p = f(T). There is an opinion that zinc pyrovanadate undergoes a first-order phase transition at 893 K [9]. The peak of the heat capacity of Zn 2 V 2 O 7 observed in curve C p = f(T) has most likely symmetric, not a λ-shape, form.…”

“…It can be suggested that the attention to solid solutions based on Cu 2 -x Zn x V 2 O 7 is also related to these properties. There are data on the structure [8], the phase relationships in the temperature range from room temperature to the melting temperature [9], and magnetic properties of these materials at low temperatures [10][11][12]. However, their properties are scantily known, despite such an interest in them.…”

Magnetic structure and Dzyaloshinskii-Moriya interaction in theS=12helical-honeycomb antiferromagnetα−Cu2V2Gitgeatpong1, Zhao2, Avdeev3 et al. 2015Phys. Rev. B513210View full textAdd to dashboardCite

“…[14][15][16] The α-phase of Cu 2 V 2 O 7 crystallizes in the orthorhombic system of space group Fdd2 with a = 20.645(2)Å, b = 8.383(7)Å, and c = 6.442(1)Å. 17,18 Structurally, Cu 2+ ions that are surrounded by five oxygen ions appear to form a chain of edge sharing CuO 5 polyhedra while the nonmagnetic V 5+ ions, each of which is surrounded by four oxygen ions to form V 2 O 7 double corner-sharing tetrahedra, are intercalated between the chains as shown in Fig.…”