Hexol is a cobalt compound that was first prepared by Alfred Werner in 1914 and represented the first non-carbon-containing chiral compound. The salt with the molecular formula of [Co((OH)2Co(NH3)4)3](SO4)3 was prepared starting from cobalt(II) sulfate.
Optical resolution of this compound was possible by treating the hexol chloride salt with the resolving agent silver d(+)-bromocamphorsulphonate in dilute acetic acid. The d-Hexol salt precipitated out from solution and the filtrate contained the l-hexol species. Werner also published a second achiral hexol (a minor byproduct from the production of Fremy's salt) that he incorrectly identified as a linear trimer.
In 2004 the second hexol was reinvestigated and found to be a hexanuclear species.