Potassium, rubidium and ammonium salts of μ-(formato-κ2O:O′)-μ-oxido-bis[oxidobis(peroxido-κ2O,O′)molybdate(VI)]

The unit-cell parameters of the three title salts, namely, tripotassium, K3[Mo2(CHO2)O3(O2)4], trirubidium, Rb3[Mo2(CHO2)O3(O2)4], and triammonium μ-(formato-κ2O:O′)-μ-oxido-bis[oxidobis(peroxido-κ2O,O′)molybdate(VI)], (NH4)3[Mo2(CHO2)O3(O2)4], which were all crystallized at pH 3, are quite similar, but the potassium and rubidium salt structures are noncentrosymmetric, whereas that of the ammonium salt is centrosymmetric. Formate acts as anO:O′-bridging ligand in the complex anion and is bound to a μ-oxido-bis(oxidodiperoxidomolybdate) unit.

Solid State Transitions in Alkali Alkanoates: Diffractometric and Conductometric Measurements on Rubidium and Cesium Propanoates

Conductometric measurements on solid rubidium and cesium propanoates and X-ray powder diffraction measurements on the rubidium salt have been carried out over suitable temperature ranges. The results obtained, along with the previous ones concerning the lithium, sodium and potassium salts, have been discussed in relation to possible melting mechanisms (involving various kinds of disorder, e.g., positional, orientational, conformational) active in the alkali alkanoates family.