[meteorite-list] More Questions - meteoritics

From: colin wade <ceweed_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:12 2004
Message-ID: <002501c09f9e$b21d7ce0$02000003_at_colinwad>

Hi Robert & list
You'll be asking how many digits of pi we can calculate next !!!!
2 riyals worth from Qatar
The valence state will reflect the oxidation potential , transition elements
tend to be variable valent depending on the oxidation potential &
temperature eg Fe FeO Fe3 04 Fe2 O3 classic examples .The oxidant can be any
radical O ,S, CO3, SO4 etc .
this property per se doesn't affect the water of crystallisation .
The text relates to 2 separate conditions dryness & low oxygen potential .
the stuff would be expected reactive in an earth atmos
all the best
Col
----- Original Message -----
From: "Robert Beauford" <wendirob_at_laplaza.org>
To: <meteorite-list_at_meteoritecentral.com>
Sent: Sunday, February 25, 2001 9:38 PM
Subject: [meteorite-list] More Questions - meteoritics


> If I understood correctly, Steven Singletary kindly explained that oxygen
> fugacity refers to the measured amount of oxygen available to react in
> various environments (earth, asteroids, lunar) in regards to the formation
> of various lithologies (rock groups/types). This leads me to a further
> question:
>
> Shearer et al, Planetary Materials V.36 Reviews in Mineralogy states:
> "The moon lacks significant water and the lithologies making up its crust
> crystalized at a very low oxygen fugacity. Therefore, all lunar
> lithologies thus far sampled are anhydrous (without water) and contain
> elements in reduced valence states." (I believe valence states is
potential
> reactivity or combining power of an element (due to extra or lacking
> electrons...?))
>
> What is the significance of a reduced valence state? More or less
reactive?
> And why do valence states correlate to water presence or oxygen fugacity
> during crystalization?
>
> Also, I'm still trying to figure out the significance of "Mg/Fe+Mg of Bulk
> Planet" in terms of planetary materials.
>
> My most sincere thanks in advance to anyone willing to take the time to
> explain.
> -Robert Beauford : )
>
>
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Received on Sun 25 Feb 2001 09:48:23 PM PST