OgreMkV
Posts: 3668
Joined: Oct. 2009
|
| Quote (Henry J @ May 04 2012,14:57) | In (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2·nH2O, do the numbers after the parentheses apply to the thing before the number, or the thing after?
And how does it have 0.33 of something? Does that mean that the thing the 0.33 applies to is shared among three of everything else?
Are the metal atoms in that list all ionized to the usual oxidation number of that element? (Na +1, Ca +2, Al +3, Mg +2) |
Heh, I FINALLY get to use my geology.
OK, the parans contain options. In the first case, it can be either a sodium or a calcium in that spot.
The formula for minerals is more of a crystal structure than a chemical formula. In this case, the .33 is a mole number relating to the weight of the oxides. This is why the formula is Si4O10, instead of the chemically proper Si2O5.
Yes, the follow the normal oxidation rules, though different minerals will use different oxidations. For example wustite is FeO while magnetite if Fe2O3.
Montmorillonite has a very complex structure with a middle layer of the sodium/calcium (usually mixed with water). This layer is why clay feels slippery.
Lightly bonded to that (top and bottom is a oxygen silicon tetrahedron with the base of the tetrahedron facing the middle layer. Bonded to the top oxygen is the aluminum/magnesium. Every pair of aluminum s has a pair of OHs bonded to them (and I mean "them" not "one of them"). Then there's another oxygen silicon tetrahedron on top.
I'm sure that's as clear as mud.
--------------
Ignored by those who can't provide evidence for their claims.
http://skepticink.com/smilodo....retreat
|
