Co2+-Cu2+ substitution in bieberite solid-solution series, (Co1-xCux)SO4{middle dot}7H2O, 0.00 <= x <= 0.46: Synthesis, single-crystal structure analysis, and optical spectroscopy

Microgravity-like Crystallization of Paramagnetic Species in Strong Magnetic Fields

“…It is known that for Cu-substituted bieberite (Co1−xCux)SO4•7H2O, a solid solution forms when the copper content is within the range of 0 ≤ x ≤ 0.46. Conversely, in chal canthite CuSO4•5H2O, only up to 3% of the metal sites can be substituted by Co 2+ ions [31] Given that our study focuses on a 1:1 Cu:Co solution, which contains copper just beyond the threshold for bieberite-like solid solution formation, we anticipated the crystallization of both substituted bieberite (Co1−xCux)SO4•7H2O and chalcanthite CuSO4•5H2O from ex cess copper sulfate. These two phases are distinct not only in their water content, but also in their crystal systems and symmetries-the heptahydrate is monoclinic ( 1 2 / P c spac group), while the pentahydrate is triclinic ( 1 P ).…”

The copper sulfate hydration cycle. Crystal structures of CuSO4 (Chalcocyanite), CuSO4·H2O (Poitevinite), CuSO4·3H2O (Bonattite) and CuSO4·5H2O (Chalcanthite) at low temperature using non-spherical atomic scattering factors

“…6) is clearly very similar to aqua Cu(II). 43 In a tour de force investigation, Wildner and colleagues have reported a detailed polarized electronic absorption spectrophotometry study of crystalline anhydrous CuSO 4 , in part to address ''the perplexing absence of colour of chalcocyanite, CuSO 4 ''. 44 Their spectra demonstrate that the band maximum shifts to 11 720 cm À1 and that the band profile has a steep rise to this peak, followed by further shoulders at lower energies.…”

“…The tetragonally elongated structures (see above) have effective D 4h symmetry (4 + 2 coordination) and Redhammer et al have shown that the E g level is strongly split, approximating to that of a square planar geometry. 43 The highest energy d-d transition, 2 Eg -2 B 1g , is therefore dominated by the crystal fields of the equatorial ligands. In 1 all four of these are sulfato oxygen donors, whereas in 3 there are one sulfato and three water O donors, and in 4 all four donors are water (hence the similarity of the optical spectrum of 4 and aqua [Cu(OH 2 ) 6 ] 2+ is not surprising).…”

Cation substitution in synthetic meridianiite (MgSO4·11H2O) II: variation in unit-cell parameters determined from X-ray powder diffraction data

“…It is known that Cu 2? prefers to occupy the M2 site in both Fe7 (Peterson 2003) and Co7 (Redhammer et al 2007), but it is not at all clear why Mg 2? should prefer different sites in the Fe-and Mn-bearing heptahydrates and until we are able to obtain single-crystal data for Mg-doped Fe7 and Mn7, no further conclusions can be drawn.…”

“…Wildner and Giester (1991) determined the unit-cell parameters of end-member monohydrates Mn1, Fe1, Co1, Ni1 and Zn1; Giester et al (1994) and Lengauer and Giester (1995) presented results as a function of composition for the Cu1-Fe1 and Cu1-Mg1 systems. Lastly, Redhammer et al (2007) reported changes in unit-cell parameters of Co7 with increasing Cu 2? concentrations, up to 46 mol.…”