Synthesis and structural characterization of β-(NH4)2Mo4O13 by direct "reducing ammonium" in situ transformation method.

[Display omitted] • Simple routes of "reducing ammonium" in-situ transformation method for β -(NH 4) 2 Mo 4 O 13 synthesis are presented. • The β -(NH 4) 2 Mo 4 O 13 powder was synthesized at temperature of 473.15 K with little water participating in reaction. • The cleaner and cost-effective conversion was achieved with neither large amount of water nor using of acid. • Structural evolution was studied by XRD, TG-DTA, FESEM, FTIR, Raman and UV–vis spectroscopy. A new environmentally friendly strategy for the synthesis of β -(NH 4) 2 Mo 4 O 13 powders is presented using a direct "reducing ammonium" in situ transformation method from (NH 4) 2 Mo 2 O 7. The crystal structure of the resulting β -(NH 4) 2 Mo 4 O 13 was first characterized using X-ray diffraction analysis. The title compound crystallizes in a triclinic system, space Group P -1(2), a = 8.250 Å, b = 8.331 Å, c = 10.240 Å, α = 104.686°, β = 106.077°, γ = 109.614°, Z = 2. The TG-DTA results showed that no intermediate products were generated in the thermal decomposition process from β -(NH 4) 2 Mo 4 O 13 to MoO 3. A comprehensive study of the newly synthesized β -(NH 4) 2 Mo 4 O 13 was performed by FESEM, FTIR spectroscopy and Raman spectroscopy. The band gap energy of the synthesized β -(NH 4) 2 Mo 4 O 13 was 3.26 eV, which shows a good intense absorption band in the visible light region. [ABSTRACT FROM AUTHOR]