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The new layered compound [FexMn1−x]Ta(O2)O2 (x ≈ 0.3) has been prepared and structurally characterized. This compound crystallizes in orthohombic system (C22v - Pmc21), a = 4.726(1), b = 5.697(2), c = 4.963(1)A with two formula units in the cell. The structure contains Ta and M atoms in unusual trigonal prismatic environments with the TaO distances ranging from 1.74(2) to 1.995(9) A, and the MO distances from 2.10(2) to 2.24(2) A. Each M site is statistically occupied by about 30% Fe atoms and 70% of Mn atoms (M ≈ 0.3 Fe + 0.7 Mn). Metrical details are discussed. Results of electrical resistivity measurements on the new material indicate the saturated semiconductor behavior along the c-axis.

The six Mo atoms in the title compound, (C4H12N)2[Mo6O19].H2O, form a standard octahedral cage through bridging O atoms. The [Mo6O19]2− anion as a whole has Oh symmetry with three crystallographic fourfold axes aligned along Mo—O—Mo. There exist weak O⋯O hydrogen bonds (O100⋯O3 2.951 A) between the terminal O3 atoms of the anions and O100 atoms of the solvate hydrates in the unit cell.