AW: Jaws, claws and stings containing 25% Zinc by dry mass

Koehler Thomas ( "Koehler )
Fri, 22 Aug 1997 10:13:29 +0200

> >I am on somewhat of a fishing expedition: We have found that jaws,=20
> >claws, stings and other "tools" in a variety of arthropods and
> annelids=20
> >contain up to 25% Zn by dry mass. I am not aware of any similar=20
> >applications of Zn so we know nothing about the form that the zinc=20
> >may be in. Exafs of specimens from a variety of organisms indicates =

> >that the coordination number is between 3.8 and 4.6 and that the=20
> >first shell radius is between 1.95 and 2.0. The donors are either =
all
> >O, all N, or N and O. The Debye-Waller factors were rather high
> >(0.02) suggesting a heterogeneous coordination environment.
> >Elemental analysis has eliminated all elements except C, H, O, and =
N.
>=20
> >The zinc concentrations are too high for it to be an organic
> compound.
>=20
Regarding the informations above, I would gess it may be some zinc
carbonate, hydroxycarbonate etc. Nitrates are not likely, because they
are easily soluble in water. If the material is not amorphous, simple
X-Ray qualitative phase analysis will probably do the job. If its
amorphous, he may learn something from infrared spectroscopy comparing
spectra from his samples with spectra from zinc minerals like
smithsonite, hydrozincite ...

Thomas K=F6hler