# What can we deduce about a (complex, organic) molecule's structure from the order of elements in its formula?

According to IUPAC, a hemiacetal is a compound having the general formula $\ce{R2C(OH)OR'}$ $\ce{( R' ≠ H )}$.

What does the order in which the elements of this formula appear tell us about the connectivity of this molecule? Does it tell us anything besides that a compound with this formula is composed of a carbon, a hydroxyl group, a oxygen, a $\ce{R2}$ group and a $\ce{R'}$ group? Or does it contain any information about how these elements and groups are connected with each other, about the compound's structure?

Surely the order in which these elements appear isn't arbitrary.

• The formula tells you that the two R groups are bonded to carbon as are OH and OR'. The (OH) is written that way so you don't see R2COHOR and possibly misinterpret the formula. – user55119 Nov 26 '17 at 18:31
• @user55119 Is there any reason why it's $\ce{(OH)OR'}$ and not $\ce{(OR')OH}$? – Qwedfsf Nov 26 '17 at 18:54
• I don't see why not. Perhaps there is a rule. Clarity is important. – user55119 Nov 26 '17 at 18:59
• – Loong Nov 27 '17 at 6:34