Characterization of the compounds formed from the interaction of divalent cations with inorganic molecular metal—oxygen cluster compounds

Synthesis and crystal structure of hexaaquamagnesium hydrogen phosphododecatungstate tetrahydrate [Mg(H2O)6][HPW12O40]·4H2O

“…Reports of solid 12-tungstophosphoric acid salts containing divalent cations are quite rare [16,18,37,39,40]. Although such salts are often reported to be of low crystallinity [16] or to have not been formed at all [18], we have found that it is possible to obtain the salts of good crystallinity starting from a chloride solution of the corresponding cation and preserving the pH of an acid solution in the region from 1.0 to 1.2.…”

“…Although such salts are often reported to be of low crystallinity [16] or to have not been formed at all [18], we have found that it is possible to obtain the salts of good crystallinity starting from a chloride solution of the corresponding cation and preserving the pH of an acid solution in the region from 1.0 to 1.2. Under such conditions Keggin anions are stable [41,42].…”

“…The inspection of the Inorganic Crystal Structure Database (ICSD) [50] showed that for all reported structures (20) [16,18,39,40] and stability of HPA in aqueous solutions [41,42], we have synthesized all salts of alkali and alkali earth cations starting with chloride aqueous solutions [51,19,20] . Such a solution of WPA was strongly acidic (pH = 1.1).…”

“…Moreover, the catalytic and conductive activities of HPAs salts are close to the catalytic activity and conductive characteristics of HPAs [14][15][16]. While different HPAs forms and their salts containing monovalent cations have received the most attention [14,15,17], there are only few reports concerning general properties of dodecatungstophosphoric acid (WPA) salts with divalent cations [16,[18][19][20]. It has been shown that the Mg salt of WPA (Mg-HWPA) is highly active in the conversions of methanol to hydrocarbons [16].…”

Synthesis and characterization of soluble alkali metal, alkaline earth metal and related Keggin-type [PMo12O40]3− salts for heterogeneous catalysis reactions

“…[7,[13][14][15][16]. However, two fairly recent publications have suggested that soluble alkaline earth metal salts prepared by the reaction of H 3 [PMo 12 O 40 ] (and also H 3 [PW 12 O 40 ]) and the alkaline earth hydroxides, which were characterized by infrared spectroscopy, X-ray powder diffraction (XRD), differential thermal analysis and nitrogen adsorption-desorption measurements, are, in fact, a mixture of simple divalent salts and the parent acid itself [17,18]. Moreover, a single-crystal X-ray structural investigation of the product obtained from the Ba 2+ /[PMo 12 O 40 ] 3− system gave a unit cell effectively identical with that of the hydrated acid, H 3 [PMo 12 O 40 ]·(29-30)H 2 O [18][19][20] and, furthermore, the Ba 2+ ions could not be located within the unit cell, supporting the above conclusion.…”