Crystal of KCoPO4 were obtained by growth in a gel of tetramethoxysilane/H2O at 64 Deg. The hexagonal crystals have space group P63, a 18.206(1), c 8.5135(8) .ANG., Z = 24. At. coordinates are given. The structure is isotypic with a-KZnPO4. It comprises an ordered three dimensional network of alternating CoO4 and PO4 tetrahedra, which has rings of six tetrahedra of six tetrahedra in the xy plane. These rings from tunnels in the [001] direction, where the K ions are located. Upon heating, the compd. undergoes a phase transition at .apprx.565 Deg; on cooling, the phase transition occurs at 449 Deg, where it transforms into another structure which is yet unknown. The hexagonal structure is a metastable phase.