화학공학소재연구정보센터
Inorganic Chemistry, Vol.48, No.19, 9147-9154, 2009
Investigation of the New P' 3-Na0.60VO2 Phase: Structural and Physical Properties
A new layered phase Na0.60VO2 was synthesized by chemical deintercalation of sodium from the pristine compound O3-NaVO2. The Na0.60VO2 compound exhibits a distorted P'3-type oxygen stacking (AABBCC) with an average monoclinic unit cell containing a = 4.9862(14) angstrom, b = 2.8708(8) angstrom, c = 5.917(2) angstrom, and beta = 104.36(3)degrees. A modulated structure was observed by transmission electron microscopy and X-ray diffraction (XRD) measurements. Indexation of the XRD pattern was achieved by using the q vector equal to 0.44b(star), and the 4D superspace group C2/m (0 beta 0) s0 was then deduced. The specific heat measurement showed a strong correlated system with a gamma value of around 20 mJ . mol(-1) . K-2. The electrical conductivity shows a semiconductor-like behavior with an activation energy of 0.52 eV. A paramagnetic behavior of the susceptibility is observed below room temperature with a Curie constant equal to C = 0.076 emu . K-1 . mol(-1) . Oe(-1). To explain this small value, a model of pseudotriangular clusters of vanadium with a random distribution of V3+ and V4+ was considered.