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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Morphic flip on August 18, 2006, 05:19:28 AM

Title: unit cell structure
Post by: Morphic flip on August 18, 2006, 05:19:28 AM

From the YBa₂Cu₃O₇ structure, I know it is made up of layers virtually identical to that of perovskite.
But I can`t determine whether YBa₂Cu₃O₇ has B type unit cell sandwiched between two A type unit cells, or something similar.
Any pointers please?

Title: Re: unit cell structure
Post by: GCT on August 19, 2006, 09:05:34 PM

Quote from: Morphic flip on August 18, 2006, 05:19:28 AM

From the YBa₂Cu₃O₇ structure, I know it is made up of layers virtually identical to that of perovskite.
But I can`t determine whether YBa₂Cu₃O₇ has B type unit cell sandwiched between two A type unit cells, or something similar.
Any pointers please?

In one of my undergraduate labs we had to synthesize this compound and then determine various physical properties as well as the structural characteristics of it (including the charge of the copper through an iodometric redox titration).  I don't remember the structure exactly, however, it is a "three unit cell/elongated" representation.  You can probably search the net to find this info right away, and if not simply deduce it by understanding the proportionalities involved with having the particular atom at the edge, corner, middle, face etc locations.  For instance, you may expect copper to have one atom constituents in each of the cell (one copper in each cell), however, from this wouldn't make sense in light of some practical as well as theoretical considerations.  It's probably just better to find the structure on the web, try googling "hyperphysics" and "YBa2Cu3O7."

Title: Re: unit cell structure
Post by: Morphic flip on August 21, 2006, 11:48:01 AM

cheers for input.
I have already tried on google, but can`t find anything definitive.
Als, what is the coordination of oxygen to the cations?
Like oxygen to Y?