(Cu_xZn_1–x)_0.456In_1.084Ge_0.46O₃ (0 ≤ x ≤ 1): A Complex, Ordered, Anion-Deficient Fluorite with Unusual Site-Specific Cation Mixing

Abstract

The anion-deficient fluorite-related family of materials exhibits a number of commercially useful properties arising from the specific arrangement of anion vacancies in each structure. One recently reported member, Zn 0.456 In 1.084 Ge 0.46 O 3 , is the only known example with its particular complex structure in which cation coordinations span one 4-coordinate (4b), two 6-coordinate (8e and 16f), and one 8-coordinate (4a) site. A new, complete, solid solution (Cu x Zn 1−x ) 0.456 In 1.084 Ge 0.46 O 3 , (0 ≤ x ≤ 1) has been discovered via the isovalent substitution of Cu 2+ for Zn 2+ , significantly expanding the known phase space of this structure. Synchrotron X-ray data confirm the ZIGO structure over the entire composition range. Inclusion of Cu in the structure is found to occur exclusively at the 16f site, increasing the number of cations mixed on that site from three to four, while all others remain singly occupied, including the other 6-coordinate (8e) position. Furthermore, transmission electron microscopy investigations show no evidence of long-range cation ordering. Thus, disorder on the 16f site appears remarkably favorable in this otherwise highly ordered structure. Nonideal trends in the lattice parameters and diffuse reflectance spectra as a function of Cu content are examined. Further implications of the mixed order and disorder in the solid solution for materials discovery and possible properties of interest are briefly discussed.

Solid‐state nuclear magnetic resonance of spin‐9/2 nuclei 115In and 209Bi in functional inorganic complex oxides

“…The gallium spectra contain a number of overlapping sidebands at moderate MAS rates F I G U R E 5 209 Bi nuclear magnetic resonance (NMR) of (a) BiAlTeO 6 and (b) BiGaTeO 6 . Experimental data in blue, spectral simulations in orange (10)(11)(12)(13)(14)(15)) that are much smaller than the CT linewidths; this problem is alleviated for 71 Ga but not entirely for 69 Ga at 35 kHz MAS (Figure 7). In each case, the features under static and variable MAS rates could be readily simulated with second-order perturbation theory (Table 3).…”

“…[9][10][11] Complex indium-containing oxides are being developed for the next generation of electronic materials. [12][13][14][15][16] Lithium indium oxides have been studied as prospective solid electrolytes for all-solid-state lithium-ion batteries. [17][18][19] Substituted versions of fluorite bismuth oxide (δ-Bi 2 O 3 ) [20][21][22][23] and Aurivillius-type mixed-metal bismuth oxides [20,24,25] host some of the highest known oxygen-ion conductivities.…”

Identification of Structure and Chemical Occupancy of Emerging Complex Compounds via Analytical Electron Microscopy

“…Based on the structure of ZIGO, we hypothesized that Cu replacement of Zn at the 16f site is favored over the 4a, 4b, and 8e sites. This hypothesis is strongly supported by bond valence (BV) analysis and the literature on related phases [3]. In order to directly determine the elements in the cation position, we use the contrast on the HAADF image that sensitively depends on the atomic number.…”

“…Zn0.456In1.084Ge0.46O3 (ZIGO) structure is the only known example with its particular complex structure in which cation coordination span one 4-coordinate (4b), two 6-coordinate (8e and 16f), and one 8-coordinate (4a) site, as shown in the left of Figure 1 [2]. A new, complete, solid solution has been discovered via the isovalent substitution of Cu 2+ for Zn 2+ , significantly expanding the known phase space of this structure [3].…”

Solid-State NMR of Spin-9/2 Nuclei 115In and 209Bi in Functional Inorganic Complex Oxides

“…Complex indium-containing oxides are being developed for the next generation of electronic materials. [12][13][14][15][16] Lithium indium oxides have been studied as prospective solid electrolytes for all-solid-state lithium-ion batteries. [17][18][19] Substituted versions of fluorite bismuth oxide (-Bi 2 O 3 ) [20][21][22][23] and Aurivillius-type mixed-metal bismuth oxides 20,24,25 host some of the highest known high oxygen-ion conductivities.…”