Beryllium 10 on Titan? Options

[ngunn]

Like Earth, Titan is a world with many active processes operating, no doubt, over a wide range of timescales. In such an environment anything that can act as an absolute time marker in the landscape has the potential to yield a rich store of information. In an eye-opening paper* now a decade old Lorenz et. al. lay out this potential in respect of radiocarbon. They point out that not only will C14 be produced by the action of cosmic rays on Titan’s atmosphere but Titan has, in the formation of solid haze particles, a mechanism for removing it from the air and depositing it on the surface in solid or liquid form. Indeed Titan is probably the only place in the Solar System other than Earth where such a mechanism operates and where, as a consequence, there is the potential to use radiocarbon to track and date active processes in the landscape. The timescale involved is from centuries to a few tens of millennia, commensurate with the half-life of C14.

Well, there is another radioactive species produced by the action of cosmic rays on atmospheric nitrogen, namely beryllium 10. It has a much longer half-life, around 1.3 million years, which could make it the perfect complement to C14 by taking over the role of landscape marker for timescales in the range 10^5 t 10^7 yr. On Earth it is used as a tool for studying palaeoclimate. My (inexpert) searches have not turned up any references to Be10 on Titan so I thought I’d post my questions here. I’ve read enough to be sure that Be10 must form in Titan’s atmosphere, just like C14, so my questions are:

1/ Are there papers out there that I haven’t found where this is mentioned or discussed?

2/ If not, has anybody heard it raised informally, at a conference or whatever?

3/ What would likely happen to the Be 10 once formed? How would it react chemically? Would it be incorporated into haze particles or other precipitation and thereby end up in lakes and sediments?

* http://www.google.co.uk/url?sa=t&rct=j...VCg&cad=rja

[Juramike]

I would assume that the berylium would drift down in the atomspheric fallout and exist as isolated atoms in a matrix or organics.

Would it be mobile (soluble) and leach out of the matrix? Probably not.

Beryllium itself likely would not dissolve in organic solvents. Beryllium is also pretty oxophilic, so if it did manage to react with water/ice it would convert over to the oxide form BeO (releasing one molecule of H2), which should be also pretty insoluble in organic solvents. [Beryllium metal is not reactive with oxygen at room temperatures, but it might be due to an thin oxide coating - when dealing with a single isolated atom I'd assume oxidation happens] Beryllium can also form a cation in water [Be(H2O)4]2+

At high temperatures (maybe in rarefied environments in upper atmosphere?) beryllium can react with nitrogen to make the nitride Be3N2 (readily hydrolyzed by water, but we'll assume that doesn't happen). It can also react with ethylene at high temperatures to form BeC2 (+ 2
H2).

The solubilities of the Be compounds is pretty poor in organic solvents, even though the bonds have predominantly covalent character. (Cotton and Wilkinson 3rd ed.)

Link to article with solubility data (starting on p.8): http://ntp.niehs.nih.gov/ntp/newhomeroc/roc10/be.pdf

So yeah, it's a good idea, any beryllium atoms that drift to the surface and get stuck in layers should stay there and be a great marker, unless there was some type of aqueous event, like an impact melt pool or something.

[PFK]

I would assume that the berylium would drift down in the atomspheric fallout and exist as isolated atoms in a matrix or organics.

Interesting question isn't it, because you're generating it literally one atom at a time. So determining "reactivity" would be tough - there have been studies on the reactivity of laser ablated Be atoms with methane:
e.g. T.M Greene, D.V Lanzisera, L Andrews and A.J Downs. J. Am. Chem. Soc., 120 (1998), p. 6097
"Beryllium atoms produced by laser ablation have been co-condensed with methane/argon mixtures onto a substrate at 10 K. Infrared spectroscopy has been used to identify a number of organoberyllium products, viz. CH3BeH, CH3BeCH3, CH3Be, H2CBeH, and HCBeH. "

As an aside, it's always one of the more nerve wracking times in a lab when someone else in there is using Be compounds. They're not the nicest - in fact Guinness used to note Be as being the most toxic non radioactive element. Nature is at its slyest, therefore, when it plays the trick of making Be compounds taste sweet! Mind you, I've only ever known one person test that!