A STUDY ON THE PREPARATION AND PHYSICAL PROPERTY DETERMINATION OF NAVO2
A STUDY ON THE PREPARATION AND PHYSICAL PROPERTY DETERMINATION OF NAVO2
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DOI：
10.1016/0022-4596(88)90124-7
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发表时间：
1988-04-01
影响因子：
3.3
通讯作者：
PORTER, SK
中科院分区：
文献类型：
--
作者：
CHAMBERLAND, BL;PORTER, SK
在650 ° C下，通过氢还原NaVO3或Na2CO3和V2O5的混合物制备了化学计量和近化学计量的NaVO2相。黑色还原产物立即与空气反应，生成非化学计量的NaxVO 2相，并形成NaOH。化合物的化学计量可以通过在吸气氩气气氛下在干燥箱中工作来保持。纯NaVO2，其特征在于通过X-射线衍射研究，热分析方法，和磁性测量。通过差示扫描量热法实验在115 ° C下注意到半可逆晶体学转变。然而，这种转变非常微弱，而且相当广泛。在室温下，NaVO2呈正交晶系，但在相变温度以上，NaVO2呈α-NaFeO2结构。磁性表明钒中心之间存在适度的相互作用，这将总磁矩降低到约1.2 μ B的值，该磁矩远低于三价钒的自旋磁矩。
Stoichiometric and near-stoichiometric NaVO2phases have been prepared by the hydrogen reduction of NaVO3or mixtures of Na2CO3and V2O5at 650°C. The black reduction products react instantly with air to generate nonstoichiometric NaxVO2phases with the formation of NaOH. Stoichiometry of the compound could be maintained by working in a dry box under a gettered argon atmosphere. Pure NaVO2was characterized by X-ray diffraction studies, thermoanalytical methods, and magnetic measurements. The semireversible crystallographic transition was noted at 115°C by means of a differential scanning calorimetry experiment. This transition, however, is very weak and quite broad. At room temperature, NaVO2appears to be orthorhombic, but above the transition temperature, it adopts the α-NaFeO2structure. The magnetic properties indicate a moderate interaction between vanadium centers which reduces the overall magnetic moment to a value of approx 1.2 μB, a moment which is much lower than that expected for the spin-only moment for trivalent vanadium.