Simulation of powder diffraction patterns of mixed-layer compounds in the restacked binary nanosheet system Ti0.91O2-MnO2.

Two-component colloidal nanosheets in a Ti0.91O2--MnO2system with different compositions were restacked by flocculation with K ions. X-ray powder diffraction patterns of the products showed remarkably broad reflections. The structures suggested the presence of mixed layers of Ti0.91O2 and MnO2 connected by K ions. Powder pattern simulation was conducted using the matrix method, in an approach similar to that used for analyzing layered composite crystals with one-directional disorder. The following were considered: (1) stacking disorder in layered K-Ti-oxide, (2) stacking disorder in layered K-Mn-oxide, and (3) sequence probabilities of K-Ti-oxide and K-Mn-oxide sheets. Taking into consideration chemical composition, three types of probability tables were unified into one large probability table. For 00ζ calculation, z coordinates of all atoms were used. For h1k1ζ calculation except 00ζ, atom coordinates of the K-Ti-oxide sheet were used on an orthorhombic cell (a1 = 2.96, b1 = 3.77, C1 = 9.32 Å), and for h2k2ζ calculation except 00ζ those of the K-Mn- oxide sheet were used on a trigonal cell (a2 = b2 = 2.84, c2 = 7.10 Å). The agreement in pattern fitting between the experimental and calculated intensities was satisfactory in all composition ranges. From the results, the phase relationship of the misfit mixed-layer material in the binary restacked nanosheet system of Ti0.91O2--MnO2 flocculated with K ions was clarified. [ABSTRACT FROM AUTHOR]