Precision Determination of the Crystal Structure of Osmium Dioxide.

Comparison of reductive accumulation of Re and Os in seawater–sediment systems

“…The calculated interatomic distances for the Os-Cl ðOsCl 6 2À Þ, Os-O (OsO 2 ), and Os-S (OsS 2 ) bonds for the reference materials are 2.316, 1.963, and 2.350 Å , respectively (N = 6). These results are comparable with previous reports; the ideal interatomic distances for Os-Cl bond in OsCl 6 2À , Os-O bond in OsO 2 , and Os-S bond in OsS 2 are 2.261, 1.961, and 2.351 Å , respectively (Boman, 1970;Cotton and Rice, 1977;Stingl et al, 1992). Therefore, the quality of the XAFS measurements and EXAFS analysis results using FEFF7.0 is acceptable.…”

“…When Cl or S was assumed to be the first neighboring atom of Os for the two sediment samples of UTS-G2 (OsO 4 ) and UTS-G2 ðOsCl 6 2À Þ, it becomes apparent that the calculated interatomic distances of Os-Cl (2.149-2.186 Å ) and Os-S (2.168-2.217 Å ) bonds were shorter than those expected from the analyses of reference materials. In contrast, when O was assumed to be the first neighboring atom of Os, the interatomic distances (1.984 or 2.017 Å ) obtained for both sediments become comparable to that of the Os-O bond (1.961 Å ) in a previous report (Boman, 1970). The EXAFS results reveal that the first neighboring atom of Os in the sediment is O and that the interatomic distance of the Os-O bond ranges from 1.984 to 2.017 Å .…”

Insights into the electronic structure of OsO2 using soft and hard x-ray photoelectron spectroscopy in combination with density functional theory

“…In good agreement with previous reports, OsO 2 crystallizes in the well-known rutile structure (see inset in Fig. 1), with lattice parameters of a = 4.49907(3)Å and c = 3.18555(5)Å [14,16,40]. The structure parameters found for the present samples, literature values, and the values derived from theory are summarized in Table I.…”

“…OsO 2 itself is a metallic low-spin d 4 compound with a reported room-temperature resistivity on the order of 1.5-6.0 × 10 -5 cm [14,15]. Very little is known about this oxide due to the difficulty of obtaining high-quality samples and its tendency to form OsO 4 , a highly volatile and toxic compound, as on heating or sputtering OsO 2 readily disproportionates [16,17]. Therefore, experiments with OsO 2 , and particularly surface science measurements, suffer from significant limitations regarding sample treatment and surface preparation, which has restricted the study of OsO 2 to date.…”

“…The spin orbit splitting TABLE I. Crystal structure parameters from the literature [14,16,40] from Rietveld refinement of PXRD data and from DFT calculations. a and c are the lattice parameters, c a is their ratio, and V is the unit cell volume.…”