rac-Hy-droxy-isovaleric acid.

The title compound (systematic name: rac-2-hydroxy-3-methylbutanoic acid), C5H10O3, is the constitutional isomer of α-hy-droxy-butanoic acid. In the crystal, hydrogen bonds involving the alcoholic hydroxyl group give rise to centrosymmetric dimers that are extended to sheets perpendicular to the crystallographic c axis.

[1,1'-Bi-cyclo-hexa-ne]-1,1'-diol.

The title compound, C12H22O2, is a symmetric diol derived from the pinacol coupling of cyclo-hexa-none. The asymmetric unit contains three complete mol-ecules. The cyclo-hexane moieties adopt chair conformations. Cooperative hydrogen bonding connects the individual mol-ecules to infinite chains propagating along the crystallographic a-axis direction.