Collect. Czech. Chem. Commun. 1985, 50, 317-328

Formation of salts of heteropolyacids in nitrate melts

Milan Drátovskýa and David Havlíčekb

a Department of Inorganic Chemistry, Charles University, 128 40 Prague 2
b Institute of Atmosphere Physics, Czechoslovak Academy of Sciences, 140 00 Prague 4


The acid-base reaction between Na2MoO4 + Na4As2O7 as Lux bases dissolved in an NaNO3 + KNO3 melt and an NO2 + O2 gas mixture as a Lux acid gave a novel heteropolyacid salt whose composition is approximately (Na, K)18As2Mo17O65, (Na, K)16As2Mo18O56, (Na, K)16As2Mo17O64. This compound can also be obtained by direct fusion of the components (Na4As2O7, Na2MoO4 and MoO3) over the temperature region of 420-600 °C. Based on the study of the arsenate and diarsenate ions in a nitrate melt and the molecular spectra of the compound obtained it is suggested that the basic unit of the heteropolyanion structure is the diarsenate anion. The formation of analogous compounds can generally be expected for X/Z combinations with X = P(V), As(V), V(V) and Z = Mo(VI), W(VI).