The Crystal Structure of K7Nb(SO4)6 and K7Ta(SO4)6.

Potassium bis(μ-sulfato-1κO:2κO′)bis[cis-dioxido-cis-bis(sulfato-κO)tungstate(VI)]

“…Studies of the vanadium-based catalyst (Topsøe & Nielsen, 1947) used in industrial sulfuric acid production, where potassium pyrosulfate is the solvent, have led to the determination of the K 2 S 2 O 7 -V 2 O 5 phase diagram (Folkmann et al, 1998), the characterization of both sodium and potassium pyrosulfate (Rasmussen et al, 2001), and investigations of the ability of potassium pyrosulfate to dissolve transition metal oxides in general. A diverse range of novel sulfate compounds has precipitated from these melts (Borup et al, 1990;Nørbygaard et al, 1998;Berg & Thorup, 2005).…”

catena-Poly[tetrasodium [[cis-dioxido-trans-bis(sulfato-κO)molybdate(VI)]-μ-sulfato-κ2O:O′]]

“…Related compounds with Mo replaced by W were discussed by Schä ffer & and Berg et al (2006). Other sulfato complexes coordinated to late transition metal centers were reported by Berg & Thorup (2005), Borup et al (1990), Nielsen et al (1993) and Rasmussen et al (2003).…”

Raman spectroscopy evidence of 1:1:1 complex formation during dissolution of WO3 in a melt of K2S2O7:K2SO4

“…The positions of the fundamental bands of a regular free SO 4 2À ion of T d symmetry are well known: n 1 = 983, n 2 = 450, n 3 = 1105 and n 4 = 611 cm À1 [12]. When the symmetry of the SO 4 2À ion is lowered by complex formation (Fig.…”

“…In one case, Nb 2 O 5 was found to dissolve in considerable amounts into molten K 2 S 2 O 7 at about 450 8C [1,2]. The stoichiometric properties of this and similar reactions were studied by Raman spectroscopy [3] and X-ray single crystal diffraction [4]. Other oxide salts, e.g.…”