Thank you Zelimer (and Pete) for the additional information on this subject,
and also for the words of wisdom in your closing...
"(In French we use to say "Bonne Année", meaning "Good New Year". But I
prefer by far the English wording. ***Indeed, it is not beacuse the year
is good that you'll necessarily be happy. It mostly depends on your
mental spirit and your intrinsic optimism. Some may be poor and/or ill
but still very happy.***
I therefore wish everybody to acquire a very positive mantal spirit in
any circimstance, so far for this unpredictable 2012...)"
I'll second that! HAPPY New Year to all!
Linton
----- Original Message -----
From: "Prof. Zelimir Gabelica Université de Haute AlsaceENSCMu,"
<zelimir.gabel...@uha.fr>
To: <meteorite-list@meteoritecentral.com>
Sent: Friday, January 06, 2012 2:07 AM
Subject: Re: [meteorite-list] Are_Mars_Meteorites_Magnetic?
Hi Pete,
Your statement that magnetite (Fe3O4) is one part wüstite (FeO) and one
part hematite (Fe2O3) is formally true (in terms of formula adjustment)
but not totally, regarding its physico-chemical properties and especially
its structure, that are different from what would result in a mechanical
admixture of wüstite and hematite.
Magnetite is actually a Fe(II) ferrate(III).
It should be written more correctly as Fe(Fe2O4) where the first iron is
a bivelent cation Fe(II) or Fe2+ that neutralizes an anion which is
(Fe2O4)2- and in which the 2 irons are Fe(III) or Fe3+
As Fe(II) is more electropositive than Fe(III), it preferably acts as
cation while Fe(III) ions would more readily be surrounded by enough
oxygens so as to build up an anion.
This being, I did not check whether the permeability of magnetite results
from that of wüstite or whether it is rather rearranged otherwise, which
should be far more likely in reagrd with the completely different
magnetite structural rearrangement.
Thanks you (and Greg) for your clear discrimination between "magnetism"
and "permeability", that really needed to be reminded.
More precisely, in electromagnetism, permeability is the measure of the
ability of a material to support the formation of a magnetic field within
itself. In other words, it is the degree of magnetization that a material
obtains in response to an applied magnetic field (info from Wikipedia).
Happy New Year to all!
(In French we use to say "Bonne Année", meaning "Good New Year". But I
prefer by far the English wording. Indeed, it is not beacuse the year is
good that you'll necessarily be happy. It mostly depends on your mental
spirit and your intrinsic optimism. Some may be poor and/or ill but still
very happy.
I therefore wish everybody to acquire a very positive mantal spirit in
any circimstance, so far for this unpredictable 2012...)
Zelimir
--
Prof. Zelimir Gabelica
Université de Haute Alsace
ENSCMu, Lab. LPI-GSEC,
3, Rue A. Werner,
F-68093 Mulhouse Cedex, France
Tel: +33 (0)3 89 33 68 94
______________________________________________
HAPPY HOLIDAYS!!
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