Biochemistry of Scandium and Yttrium, Part 1: Physical and Chemical Fundamentals

Horovitz, Chaim T.

doi:10.1007/978-1-4615-4313-8

Cited by 15 publications

(10 citation statements)

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“…Scandium concentrations in surface waters are invariably very low, generally in the parts per trillion (ppt) range. The limited data available on Sc concentrations in seawater indicate an average concentration of around 13 pmol L À1 ($0.6 ppt) (Horovitz, 1999). This is consistent with a profile through the Pacific Ocean that shows a gradual increase from 2 pmol L À1 (0.09 ppt) at the surface to 20 pmol L À1 (2 ppt) at the ocean floor, which is considered to be a nutrient-like profile (Amakawa et al, 2007).…”

Section: Aqueous Geochemistrysupporting

confidence: 74%

Scandium

Iain

Chassé

2016

Encyclopedia of Earth Sciences Series

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International audienceAtomic symbol: Sc Atomic number: 21 Atomic weight: 44.95591 Isotopes and abundances: 45 Sc 100 % 1 Atm melting point: 1541 C 1 Atm boiling point: 2836 C Common valences: 3+ Ionic radii: 6-fold, 74.5 pm, 8-fold, 87 pm Pauling electronegativity: 1.36 First ionization energy: 633.1 kJ/mol Chondritic (CI) abundance: 5.81 ppm Silicate Earth abundance: 16.4 ppm Crustal abundance: 21.9 Seawater abundance: 2–20 pmol/L Core abundance: $0 Properties Scandium is the lightest group 3 (IIIB) element and is the lightest of the transition metals. Its atomic number (proton number) is 21, has only one long-lived isotope, and has an atomic mass of 44.95591 u. Scandium's electronic configuration is [Ar]4s 2 3d 1 and only occurs in the trivalent state (Sc 3+) in nature. Thus, unlike most other period 4 transition metals, the geochemical behavior of scandium is not affected by redox conditions and shows lithophile behavior. The effective ionic radii in six-and eightfold coordination are 74.5 and 87 pm, respectively (Shannon, 1976), and its Pauling electronegativ-ity is 1.36. Pure scandium metal has a melting point of 1541 C at 1 atm. The International Union of Pure and Applied Chemistry considers Sc to be a rare earth element (REE) (Damhus et al., 2005); however, the ionic radius and electronic configuration of Sc are sufficiently different from yttrium and the lanthanides that it is generally excluded from discussions of the REE. History and Use Scandium was " discovered " by Lars Fredrik Nilson in 1879 by separation from rare earth mixtures from euxenite and gadolinite and is named for Scandinavia. Global production of Sc is small ($10 tonnes per year) as a by-product from mining of ores of titanium, rare earths, apatite, and uranium. Bauxites are another potential source of Sc, as it gets concentrated, along with other elements, in the " red mud " residue that results from Al processing (Deady et al., 2016). The principal uses of Sc are in Sc-Al alloys and in solid oxide fuel cells. Minor amounts of Sc are also used in a variety of other applications including electronics, lasers, and lighting. Natural Abundances The abundance of Sc in the solar system, as estimated from chondritic meteorites, is ca. 5.81 ppm (McDonough and Sun, 1995). The refractory behavior of this element in the solar nebula as well as its lithophile behavior led to the relative concentration of this element in the silicate Earth, with an estimated abundance of about 16 ppm, which is also th

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Section: Aqueous Geochemistrysupporting

confidence: 74%

Scandium

Iain

Chassé

2016

Encyclopedia of Earth Sciences Series

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“…The dissolved Y:Ni ratio is much higher than the initial condensed-phase Y:Ni ratio of 1:7. This indicates preferential oxidation and solution release of Y over Ni, consistent with the higher oxidation potential of Y (2.37 V[29]) relative to Ni (0.25 V). While SWNT D has been “purified” by the supplier, it nevertheless contains sufficient free Y to inhibit channel function, even before air oxidation is employed to remove carbon shells and increase metal bioavailability (~ 10 μM at zero carbon loss in Fig.…”

Section: Resultsmentioning

confidence: 56%

The inhibition of neuronal calcium ion channels by trace levels of yttrium released from carbon nanotubes

et al. 2009

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Carbon nanotubes (CNTs) are used with increasing frequency in neuroengineering applications. CNT scaffolds are used to transmit electrical stimulation to cultured neurons and to control outgrowth and branching patterns of neurites. CNTs have been reported to disrupt normal neuronal function including alterations in endocytotic capability and inhibition of ion channels. Calcium ion channels regulate numerous neuronal and cellular functions including endo and exocytosis, neurite outgrowth, and gene expression. Strong CNT interactions with neuronal calcium ion channels would have profound biological implications. Here we show that physiological solutions containing CNTs inhibit neuronal voltage-gated calcium-ion channels in a dose dependent and CNT-sample-dependent manner with IC50 as low as 1.2 ug/ml. Importantly, we demonstrate that the inhibitory activity does not involve tubular graphene as previously reported, but rather very low concentrations of soluble yttrium released from the nanotube growth catalyst. Cationic yttrium potently inhibits calcium ion channel function with an inhibitory efficacy, IC50, of 0.07 ppm w/w. Because of this potency, unpurified and even some reportedly “purified” CNT samples contain sufficient bioavailable yttrium to inhibit channel function. Our results have important implications for emerging nano-neurotechnology and highlight the critical role that trace components can play in the biological response to complex nanomaterials.

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“…Although an anthropogenic source of REE input into the environment is essentially unknown, elevated REE levels are increasingly being reported in archaeological soils and sediments worldwide [13,17,18]. One potential source of REEs at occupation sites may be humanoccupation detritus, particularly teeth [10,54], hair [47], bone [10,20], skin and nail fragments [24,47]. The decomposition of these materials into the soil could result in elevated concentrations of a number of REEs.…”

Section: Rare Earth Element Enrichment: Distribution and Interpretationmentioning

confidence: 99%

Deciphering the inorganic chemical record of ancient human activity using ICP-MS: a reconnaissance study of late Classic soil floors at Cancuén, Guatemala

Cook

Kovacevich

Beach

et al. 2006

Journal of Archaeological Science

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Biochemistry of Scandium and Yttrium, Part 1: Physical and Chemical Fundamentals

Cited by 15 publications

References 0 publications

Scandium

Scandium

The inhibition of neuronal calcium ion channels by trace levels of yttrium released from carbon nanotubes

Deciphering the inorganic chemical record of ancient human activity using ICP-MS: a reconnaissance study of late Classic soil floors at Cancuén, Guatemala

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