1 If the invitation says black tie, women should wear a floor-length, evening gown. 2  A tuxedo is mandatory if you're a man. 3  This is your chance to dress as if you were headed to the Oscars. 4  Black tie optional means that wearing a tuxedo or long evening gown is not mandatory, but guests should feel free to do so.
Ether is an organic functional group consisting of a disubstituted oxygen, or an oxygen atom bonded to 2 carbon atoms (if adjacent to a ketone, functional group is then called an ester).
1 Student's Guide to Understanding Ethers In organic chemistry, the ether functional group is formed of two alkyl or aryl radicals tied to an oxygen atom: R-O-R'.2  Some of the most important ethers are ethylene oxide,â¦. Student's Guide to Understanding Ethers In organic chemistry, the ether functional group is formed of two alkyl or aryl radicals tied to an oxygen atom: R-O-R'.