ChemInform Abstract: The Periodate‐Based Double Perovskites M₂NaIO₆ (M: Ca, Sr, and Ba).

Abstract

The Periodate-Based Double Perovskites M 2 NaIO 6 (M: Ca, Sr, and Ba). -The title compounds are prepared from mixtures of MF2 (M: Ca, Sr, Ba) and NaI (Pt crucible, 650°C, 18 h, yield given in g). Ba2NaIO6 is also prepared from Ba(OH)2·8H2O and NaIO4 at 650°C (yield >85%). The samples are characterized by powder XRD, SEM, IR, and Raman spectroscopy. The Ba compound crystallizes in the cubic space group Fm3m with Z = 4, whereas the Sr and Ca compounds crystallize in the monoclinic space group P21/c with Z = 2. The crystal structures consists of symmetric (for Ba) or distorted (Sr and Ca) perovskite superstructures. Ba2NaIO6 contains the first perfectly octahedral [IO6] 5unit reported. -(KUBEL*, F.; WANDL, N.; PANTAZI, M.; D'ANNA, V.; HAGEMANN, H.; Z. Anorg. Allg. Chem. 639 (2013) 6, 892-898, http://dx.

Oxide Analogs of Halide Perovskites and the New Semiconductor Ba2AgIO6

“…The relaxed lattice constant is 8.41 Å, which is in good agreement with the measured value of 8.34 Å. 34 Next we proceed to replace Na with Ag and reoptimize the structure. The DFT-PBE lattice constant of Ba 2 AgIO 6 is found to be 8.56 Å.…”

Crystal and Electronic Structures of A2NaIO6 Periodate Double Perovskites (A = Sr, Ca, Ba): Candidate Wasteforms for I-129 Immobilization

“…These data were combined with experimental measurements in Figure 7, with Raman active frequencies and mode assignments given in Table 6. The modelled and experimental data are self-consistent within systematic calibration error and are consistent with those spectra previously reported 22 .…”

“…Subsequently, De Hair et al reported the compositions A2MIO6 (A = Ba, M = Ag, K, Na, Li; and A = Sr, M = Na), using similar methods, and reported the Raman and infra-red spectra 21 . Kubel et al reported the first crystal structure determinations for the periodate double perovskites, A2NaIO6 (A = Ba, Sr, Ca, Pb), in 2013, synthesised by: solid state reaction between AF2 and excess of NaI (A= Ba, Sr, Ca); reaction of A(OH)2•8H2O and NaIO4 (A = Ba, Sr), at 650 °C in air; or precipitation from a solution of nitrates with NaOH and NaIO4 (A = A = Ba, Sr, Ca, Pb) 22 . From Rietveld analysis of powder X-ray diffraction data, Ba2NaIO6 was reported to adopt the undistorted Fm-3m aristotype structure, whereas, Sr2NaIO6, Ca2NaIO6 and Pb2NaIO6 were reported to adopt the P21/c hettotype structure, with cooperative tilting of the rock-salt ordered B-site octahedra (Glazer notation, a + b − b − ) [22][23][24] .…”

“…Kubel et al reported the first crystal structure determinations for the periodate double perovskites, A2NaIO6 (A = Ba, Sr, Ca, Pb), in 2013, synthesised by: solid state reaction between AF2 and excess of NaI (A= Ba, Sr, Ca); reaction of A(OH)2•8H2O and NaIO4 (A = Ba, Sr), at 650 °C in air; or precipitation from a solution of nitrates with NaOH and NaIO4 (A = A = Ba, Sr, Ca, Pb) 22 . From Rietveld analysis of powder X-ray diffraction data, Ba2NaIO6 was reported to adopt the undistorted Fm-3m aristotype structure, whereas, Sr2NaIO6, Ca2NaIO6 and Pb2NaIO6 were reported to adopt the P21/c hettotype structure, with cooperative tilting of the rock-salt ordered B-site octahedra (Glazer notation, a + b − b − ) [22][23][24] . However, our bond valence sum analysis 25 , using the reported crystal structure data, identified substantial deviations from formal valence states, as shown in Table S1, which may result from the limited accuracy and precision of locating the O positions.…”

A Gold(I) Oxide Double Perovskite: Ba2AuIO6

“…Since the strongest BaCO 3 absorbance is located at this wavenumber and BaCO 3 was present in all samples, this peak was attributed to BaCO 3 . 7 There was no evidence of H-I bonding. If such bonding were present, one would expect to see a H-I stretch near 2463 cm −1 .…”