Montasserasadi Dariush, Granier Mark W, Spinu Leonard, Rai Satish Chandra, Zhou Weilie, Wiley John B
Department of Chemistry, University of New Orleans, New Orleans, LA 70148-2820, USA.
Dalton Trans. 2015 Jun 21;44(23):10654-60. doi: 10.1039/c4dt03882g. Epub 2015 Jan 26.
The new double-layered perovskites, APrNb(2)O(7) (A = Rb, Cs) have been prepared by a high temperature ceramic method. Rietveld refinement of X-ray powder diffraction data confirmed the orthorhombic and tetragonal structures, respectively; RbPrNb(2)O(7) was refined in space group Imma (a = 5.4534(7) Å, b = 22.012(1) Å, c = 5.4549(7) Å) and CsPrNb(2)O(7) in P4/mmm (a = 3.8668(2) Å, c = 11.163(1) Å). (CuCl)PrNb(2)O(7), topochemically prepared by replacement of Rb(+)/Cs(+) with CuCl(+), contains a 2D Cu-Cl network between the PrNb(2)O(7) slabs (orthorhombic space group Pbam, a = 7.7328(6) Å, b = 7.7113(4) Å and c = 11.6706(3) Å). The parent compounds both show paramagnetic behavior μ(eff) (Rb) = 3.34(1)μ(B) and μ(eff) (Cs) = 3.60(2)μ(B) while the (CuCl)PrNb(2)O(7), paramagnetic (μ(eff) = 4.020(8)μ(B)) down to 20 K, exhibits antiferromagnet-like behavior below 20 K.
新型双层钙钛矿APrNb₂O₇（A = Rb、Cs）已通过高温陶瓷法制备。对X射线粉末衍射数据进行的Rietveld精修分别证实了其正交结构和四方结构；RbPrNb₂O₇在空间群Imma（a = 5.4534(7) Å，b = 22.012(1) Å，c = 5.4549(7) Å）中精修，CsPrNb₂O₇在P4/mmm（a = 3.8668(2) Å，c = 11.163(1) Å）中精修。通过用CuCl⁺取代Rb⁺/Cs⁺拓扑化学制备的(CuCl)PrNb₂O₇在PrNb₂O₇板层之间包含二维Cu-Cl网络（正交空间群Pbam，a = 7.7328(6) Å，b = 7.7113(4) Å，c = 11.6706(3) Å）。母体化合物均表现出顺磁行为，μ(eff) (Rb) = 3.34(1)μ(B) 且μ(eff) (Cs) = 3.60(2)μ(B)，而(CuCl)PrNb₂O₇在20 K以下呈顺磁性（μ(eff) = 4.020(8)μ(B)），在20 K以下表现出类反铁磁行为。
