...Mark A. Cooper; Frank C. Hawthorne; Anthony R. Kampf; John M. Hughes Abstract The decavanadate anion, [V 10 O 28 ] 6− , is a common constituent in vanadate minerals and synthetic materials, and both protonated, [H x V 10 O 28 ] (6− x )− , and mixed-valent, [(V 4+ x V 5+ 10− x )O 28 ] (6+ x...

...Mark A. Cooper; Frank C. Hawthorne; Anthony R. Kampf; John M. Hughes Abstract The decavanadate anion, [V 10 O 28 ] 6− , is a common constituent of vanadate minerals, and both protonated, [H x V 10 O 28 ] (6− x )− , and mixed-valent, [(V 4+ x V 5+ 10− x )O 28 ] (6+ x )− , derivatives also occur...

...Anthony R. Kampf; Mark A. Cooper; Frank C. Hawthorne; John M. Hughes; Barbara P. Nash; Paul M. Adams ABSTRACT Gunterite was originally assigned the ideal formula Na 4 [H 2 V 10 O 28 ]·22H 2 O. More detailed bond-valence analysis brought into question the presence of a protonated decavanadate anion...

....” The decavanadate polyanion can be considered an anionic complex; however, to choose it as defining a class would require an even higher classification level for vanadates in general, which is not possible. The decavanadates could be considered as constituting a subclass. Currently, the only subclasses apply...

...Figure 4. Crystal structure of caseyite viewed along [100]. The interstitial H 2 O groups are white spheres. The doubly protonated decavanadate anion #1 includes the V1–V5 octahedra. The normal decavanadate anion #2 includes the V6–V15 octahedra. The unit cell is shown by dashed lines. (Color...

... (1958) showed that several V-bearing oxyanions may be present in mineralizing solutions, depending on the Eh and pH of those solutions. At relatively high Eh, the decavanadate anion, [V 5+ 10 O 28 ] 6− , is stable at mildly acidic conditions, whereas its protonated derivatives, [H x V 10 O 28 ] (6...

...− decavanadate polyanion. Decavanadate polyanions represented by surface anions only (yellow and red circles), with large circles as upper surface anions, polyanion surface junctures marked with orange lines containing black rims; pale yellow shaded circles = OD and OA anions involved in hydrogen bond coupling...

... the hydrogen atoms allow us to assign the C 2/ m disordered model to the atomic arrangement. The structural unit, or anionic portion of the atomic arrangement in pascoite, is the decavanadate polyanion (V 10 O 28 ) 6− , similar to the decavanadate group found in hummerite and numerous synthetic vanadates...

... 2/ m , a 19.8442(15), b 9.9353(8), c 10.7149(8) Å, β 120.305(1)°, V 1823.9(2) Å 3 , Z = 2. Its atomic structure [ R 1 = 2.27% for F o > 4σ( F o )] is similar to that of other pascoite-group minerals. It consists of an anionic decavanadate (V 10 O 28 ) 6− structural unit and an interstitial...

... of the Slick Rock district have revealed numerous secondary vanadium minerals that result from oxidation of vanadium ore bodies that are exposed to near-surface conditions in the mining process; many of these new species contain the decavanadate anionic complex, (V 10 O 28 ) 6– , found in the pascoite family...

... contains the divanadate group [V 2 O 7 ] 4− , and dickthomssenite, Mg(V 2 O 6 )·7H 2 O ( Hughes et al . 2001 ), which contains [VO 3 ] − vanadate chains, all of the new species contain the decavanadate anionic complex [V 10 O 28 ] 6− and are members of the pascoite, Ca 3 [V 10 O 28 ]·17H 2 O ( Hughes...

... oxy-anions may be present in these mineralizing solutions ( Evans & Garrels 1958 ). The decavanadate anion, [V 10 O 28 ] 6− , is stable at relatively high Eh in mildly acidic solutions, whereas its protonated derivatives, [H x V 10 O 28 ] (6− x )− , occur at somewhat lower pH. Under more...

... contain the decavanadate anionic complex, (V 10 O 28 ) 6− , found in the pascoite family of minerals. All known minerals that contain the (V 10 O 28 ) 6− decavanadate unit are listed in Table 1 . TABLE 1 THE PASCOITE FAMILY OF MINERALS A. {V 10 O 28 } 6 − Decavanadates huemulite...

.... 2002 ), and perhaps huemulite (Na 4 Mg[V 10 O 24 ] ·24H 2 O ( Gordillo et al. 1966 ). Each of these minerals contains the decavanadate anionic complex, [V 10 O 28 ] 6− , weakly bonded by alkali and alkaline-earth cations and H 2 O molecules. Recent collecting at the Vanadium Queen mine (38°20′11″ N...

... transition-metal-centered polyhedra that link by sharing oxygen atoms between and among the polyhedra; the polyoxometalate clusters are usually anionic. Perhaps the most widely known polyoxometalate minerals are those that contain the [V 10 O 28 ] 6– decavanadate isopolyanion; the Colorado Plateau has...

... portion of the structure, and must balance the anionic charge of the decavanadate group. The interstitial complex invariably contains H 2 O molecules in addition to the cations necessary to achieve the charge balance; in the decavanadate minerals discovered to date, those cations or cationic complexes...