# Greek letters in front of inorganic/mineral formulas [duplicate]

What do Greek letters in front of the formulas for minerals/inorganic compounds mean, such as $\gamma\textit{-}\ce{Al2O3}$ or $\alpha\textit{-}\ce{Fe2O3}$?

• In general Greek letters can mean many unrelated things. In your examples they denote compound's phase. – andselisk Jul 13 '17 at 19:55
• @andselisk Are you recommending that OP edit their question to be more specific about the types of compounds they're referring to? – hBy2Py Jul 13 '17 at 20:15
• @hBy2Py I honestly don't know, you have way more experience in here. There are examples provided, which is good enough for me, though the title doesn't reflect the question and is indeed too broad. Probably OP could explicitly state whether an answer which lists all use-cases of the Greek letters in chemical notations and nomenclature is expected. – andselisk Jul 13 '17 at 20:38
• Indeed the question could be made either more precise or broader. In solid state greek letters specify a phase, in organic compound treated at molecular level they can be locators for carbon atoms adiacent to a carbonyl group (alpha the nearest and so on), specifically in sugars cyclic forms they refer to stereiisomers... No more examples come to my mind at the moment, perhaps the use of them to denote two form of the same material showing a different property of specific interest, but it is found on research paper only. This latter falls in the different phases nomenclature, too. – Alchimista Jul 13 '17 at 20:43
• rmza7, please see if my edits are true to your question. – hBy2Py Jul 13 '17 at 20:49