X-ray diffraction study of ceramic samples of SrCu1/3Nb1/3O3

Emerging cool white light emission from Dy3+ doped single phase alkaline earth niobate phosphors for indoor lighting applications

“…Fig. 1 33 The unit cell parameters were determined and are found to be a = 7.8707 Å, b = 12.2096 Å, c = 10.2881 Å and cell volume (V) = 988.680 Å 3 , which are close to those reported by Sirotinkin et al 28 The refinement finally converges to goodness-of fit parameters (χ 2 ) = 4.2%, R wp = 31.0% and R p = 25.6%. Fig.…”

“…The crystal structure of the BaNb 2 O 6 compound was reported for the first time by Sirotinkin et al in 1990, and has an orthorhombic [space group C222 1 (20)] structure with cell parameters a = 7.880 Å, b = 12.215 Å, c = 10.292 Å and Z = 8. 28 The phase purity of the as-prepared phosphors was characterized using XRD.…”

Crystal structure analysis of tungsten bronzes β-SrTa2O6 and β′-SrTa2O6 by synchrotron X-ray and neutron powder diffraction

“…First, a-SrTa 2 O 6 is isostructural to the rynersonite CaTa 2 O 6 [22], and its structure refinement (Fig. 2) could be quickly achieved (R wp ¼0.1243, R p ¼0.0955, R F ¼0.0282, and w 2 ¼ 4.95) based on the single crystal data previously reported by Sirotinkin and Sirotinkin [8]. As summarized in Table 2, the refined structural parameters of a-SrTa 2 O 6 were essentially equivalent to those of the above cited work.…”

“…As is common for complex oxides containing d 0 tantalum, niobium, or titanium, the above Sr m Ta 2n O m þ 5n compounds have been popular choices for exploring photocatalysts or dielectrics [2][3][4][5][6][7]. One particular member, SrTa 2 O 6 , is known to form in three polymorphs designated as a-, b-, and b 0 -phases [8,9], whereas the formation of a metastable defect perovskite Sr 1/2 TaO 3 [10] has been also reported. The a-SrTa 2 O 6 , often denoted as the low-temperature form, is favored in preparations below E1100 1C, while the band b 0 -SrTa 2 O 6 form at higher temperatures, roughly above 1300 and 1500 1C, respectively.…”

“…Although the above three polymorphs of SrTa 2 O 6 have been identified more than three decades ago, their crystal structures have not yet been completely compiled. While the crystal symmetry and the atomic coordinates for a-SrTa 2 O 6 were established from a single crystal diffraction study [8], structural descriptions of the high temperature b-and b 0 -SrTa 2 O 6 phases were limited to the crystal system and the unit cell dimensions [9][10][11][12][13][14]. Moreover the reported cell parameters of band b 0 -SrTa 2 O 6 are somewhat inconsistent, as summarized in Table 1.…”