Characterization of hydrated sodium molybdenum bronzes

Preparation of Hydrated Potassium Molybdenum Bronzes and Their Thermal Decomposition

“…Three endothermic peaks appeared at around 850 to 890 K, indicative of a partial melting of the sample. (11), when a small amount of protons was introduced into the hydrated sodium bronzes, a small band also appeared at around 1005 cm\. Type I hydrogen bronze shows the typical IR band at around 1005 cm\, which appeared when protons were introduced into the intrasite between oxygens of MoO octahedra (14).…”

“…However, there is no further precise information on the cation exchange. We reported (11) in detail on hydrated sodium bronzes and proposed the models of hydrated sodium bronzes. Also, there are only a few reports on other hydrated alkali bronzes (7)(8)(9)(10) However, we first tried to synthesize the hydrated potassium bronzes by ion exchange and to characterize the exchanged hydrated potassium bronzes.…”

“…The x value of the ideal composition of the hydrated sodium bronze is 0.25, but a partial replacement of Na> ions with protons usually takes place (11). There is no useful alkali reagent for reduction except sodium dithionate.…”

Hydrothermal Synthesis of the Blue Potassium Molybdenum Bronze, K0.28MoO3

“…2b, 2c, and 2d. The peak at 7.9 marked by a black triangle is very similar to the (020) re#ection peak of AD type (air-dried) hydrated potassium molybdenum bronze (24,25).…”

“…The peak at 7.93 in the XRD of the original phase (see Fig. 2d) marked by black triangles shifts to about 9.03 after heat treatment at 424 K. The shift in the peak position characterizes the change from the AD hydrated molybdenum bronze to VD type (vacuum-dried) bronze (24) during the dehydration process. The next exothermic peak at 599.1 K coinciding with a sharp weight loss was due to the phase decomposition of hydrated molybdenum bronze, in which hydrogen was removed as water molecules with oxygen atoms located in the framework of molybdenum oxide.…”