On the formation mechanism of some heteropolytungstates of the 2:11 series

Abstract

Aimed at substantiating the formation mechanism of the heteropolytungstates of the 2:11 type: [HhMm+O6Xx+O11O30](14‐m‐x‐h)‐, via complexes of the 1:11 type, attempts were made to introduce a second heteroatozn in the latter. A new, simple synthesis method was established for the 2:11 heteropolytungstates (X = P, Si; M = Ni), starting with complexes of the type [Xx+W11O39]12‐x (X = P, Si) and by using an ion exchange method (Amberlite I.R. 120. Ni2+, K+). The correctness of the supposed reaction way was demonstrated and at the same time, the close structural relationship between the hetero‐polytung̀states of the type 1:11 and 2:11 ‐was pointed out.

Present General Status of Understanding of Heteropoly Electrolytes and a Tracing of Some Major Highlights in the History of Their Elucidation

“…The 1966 observation 111 that only by comparison of measured and X-ray densities could it be unambiguously proved that the bimetallotungstate anions are 11-tungstates and not 12 tungstates was confirmed. 251 Following the 1966 formulation 252 254 Magnetic susceptibility 255 showed the Ni to be octahedral in NiZnW 11 and absorption spectra 256 showed the same for NiFeW 11 . DTA, thermogravimetry, X-ray, and IR proved that K 6 [(H 2 O)NiSiW 11 O 39 ]‚nH 2 O could be completely dehydrated at 570 °C without destruction of the structure.…”

“…In 1971, Ripan and Botar , reported preparation and properties of salts and free acid of [UThW 18 O 61 ] 6- .…”

“…Following the 1966 formulation of Simmons's [Co(H 2 O)O 5 SiO 4 W 11 O 30 ] 6- complex as an 11-tungstate with the Co 2+ replacing one W of the Keggin structure, and the 1966 paper by Baker et al establishing the class of complexes wherein a lower valent metal is substituted for an addendum in a Keggin structure, Ripan et al reformulated their NiZnW 11 , NiFeW 11 , and ZnZnW 11 complexes , and reported preparation of K 6 [NiSiW 11 O 40 H 2 ]· n H 2 O and K 5 [NiPW 11 O 40 H 2 ]· n H 2 O by a cation exchange method showed the Ni to be octahedral in NiZnW 11 and absorption spectra showed the same for NiFeW 11 .…”

“…Complexes of this structure have been prepared with the following central atoms: U 4+ , Ce 4+ , Th 4+ , Zr 4+ , Ce 3+ , Y 3+ , La 3+ , and most trivalent rare earths. 245 In 1971, Ripan and Botar 246,247 reported preparation and properties of salts and free acid of [UThW 18 O 61 ] 6-.…”

Thermolysis of Carbamoyl Azides. II. A. Novel Reduction of Azides with Elemental Copper

“…: 101", lit. : 103" [22]) and 65 mg 1105, 1020, 980, 870, 640, 595. limed (0.32 mmol, 3.2%) of 15b (m.p. : 143", see [23]).…”