tert-Butyl­glycolic acid

In the title compound, C6H12O3, which has a sterically demanding tert-butyl group attached to a hydroxy­acetic acid residue, centrosymmetric hydrogen-bonded dimers are formed; the hydr­oxy OH group functions as the donor and the double-bonded O atom of the carboxyl group functions as the acceptor. The dimer engages in inter­dimer bonding through four shorter hydrogen bonds involving two donors (the carboxyl OH) and two acceptors (the hydroxyl O atom). A three-dimensional system of hydrogen bonds is established that has channels for the hydro­phobic butyl groups along (0, 0, z) and (1\over2, 1\over2, z). There are two independent mol­ecules in the asymmetric unit.