Why These Have To Be Some Of The Better Kept PRDX4 Secrets In The World
34?cm?1 and ��1(Bg) = 783.01?cm?1. Similarly, the calculated asymmetric stretching frequencies fall between 789.14 and 843.15?cm?1, Bleomycin in vivo red-shifted by 50�C70 wavenumbers. The four components of ��2 are coalesced into a single broad band centred at 352.6?cm?1, whilst ��4 appears as a band at 403.1?cm?1. Once again, cooling blue-shifts the band centres by around 10?cm?1. The observed vibrational frequencies of the selenate ion in MgSeO4��9H2O are very similar to those of the fully hydrated free ion in aqueous solution, for which ��1 = 837?cm?1, ��2 = 348?cm?1, ��3 = 875?cm?1 and ��4 = 414?cm?1 (Walrafen, 1963 ?), but differ systematically from those we have obtained for MgSeO4��6H2O and ��-MgSeO4, and from other anhydrous and hydrated selenate crystals reported previously (Scheuermann & Schutte, 1973 ?; Berger, 1976 ?; Ti et al., 1976 ?; Park & Frech, 1989 ?; Wildner et al., 2004 ?). In other words, the selenate ion in the 9-hydrate is closer than the hexahydrate to ideal Td symmetry, which supports the crystallographic analysis presented earlier. The remaining low-frequency features, specifically a peak at 425?cm?1 and a pair of overlapping peaks at 210�C235 cm?1, are PRDX4 assigned to stretching and deformation of the Mg(H2O)6 octahedra. The Raman spectroscopic data are given in ��S3 of the supporting information. 3.4. Crystal morphology ? Examination of Fig. 8 ? reveals a straightforward rationale for the dominance of 0?1?1 and 0?1?2 forms since these are planes across which hydrogen bonds are donated to selenate O atoms; recall from ��3.2 that these are weaker learn more than the water�Cwater hydrogen bonds. The 0?1?1 planes correspond with the triangular face of the Mg(H2O)6 octahedra defined by the three monomeric waters, Ow1, Ow3 and Ow4 and the 0?1?2 planes have the highest density of octahedra. As shown in Fig. 13 ?, a fair approximation of the crystal��s morphology can be obtained by a more straightforward analysis based on interplanar spacing density, namely the Bravais�CFriedel�CDonnay�CHarker, BFDH, model (Bravais, 1866 ?; Friedel, 1907 ?; Donnay & Harker, 1937 ?): we have used the implementation of this model coded in WinXMorph (Kaminsky, 2007 ?). Note that the predicted crystal has a blockier habit; however, our crystals were grown on the bottom of petri dishes and it seems likely that they would be less platy if they were to be grown suspended in solution. Nevertheless, the predicted forms agree well with those observed in Figs. 1 ? and 2 ?. Figure 13 Morphology of the MgSeO4��9H2O crystal calculated using the BFDH method in WinXMorph and depicted in the same orientation as the crystal photographed in Fig. 1 ?. 3.5. Behaviour on warming ? Determination of the unit-cell parameters at four temperatures between 5 and 250?K (Table 8 ?) allows some initial comments to be made with respect to the magnitude and anisotropy of the thermal expansion.
