Single crystals of undoped LiWO and LiWMoO: formation enthalpies, heat capacity in the temperature range 320-997 K

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 5; no. 35; pp. 1213 - 12136
• Main Authors: Matskevich, Nata I, Shlegel, Vladimir N, Semerikova, Anna N, Samoshkin, Dmitrii A, Grigorieva, Veronika D, Stankus, Sergei V, Kuznetsov, Vitalii A, Ponomareva, Sofiya A, Zaitsev, Valerii P, Novikov, Andrei Yu
• Format: Journal Article
• Published: 14.09.2021
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d1dt01620b

The Li 2 WO 4 single crystal was first grown by applying the Czochralski technique with weight control and low-temperature-gradients. A single crystal of Li 2 WO 4 is one of the perspective materials for researching rare events. The heat capacity for a Li 2 W 1−0.0125 Mo 0.0125 O 4 single crystal has been determined by DSC calorimetry in the temperature range 320-997 K for the first time. No anomalies in the heat capacity associated with phase transitions were found. The standard formation enthalpy for the Li 2 WO 4 single crystal was studied using reaction calorimetry. It has been shown that the relation of standard formation enthalpies for Li 2 W 1− x Mo x O 4 ( x = 0.15-0) with function (1− x )W + x Mo are close to linear, which allows one to predict the thermodynamic properties for single crystals with isotopes Li 2 W 186 1−0.0125 Mo 100 0.0125 O 4 and Li 2 W 186 O 4 . It was shown that single crystals with isotopes are more thermodynamically stable than without isotopes. Li 2 WO 4 single crystal was grown using the low-temperature-gradient Czochralski technique. Formation enthalpy, lattice enthalpy of Li 2 WO 4 and heat capacity of Li 2 W 1−0.0125 Mo 0.0125 O 4 ( T = 320-997 K) were measured.