Subject: Aluminum & Boron - Covalent Bonds

In an old chemistry book, I read that in elemental boron, three atoms

share electrons in a strange type of covalent bond, which also shows 

up in boron hydrides. (Such as B2H6)  Is this theory still widely 

accepted?  It is not shown in our high school chemistry book.  If it

is still widely accepted, might this type of bonding be the reason 

that aluminum chloride molecules in the gaseous state tend to form 

pairs?

Re: Aluminum