Description of schoenfliesite, MgSn(OH) 6 , and roxbyite, Cu (sub 1.72) S, from a 1375 BC shipwreck, Rietveld neutron-diffraction refinement of synthetic schoenfliesite, wickmanite, MnSn(OH) 6 , and burtite, CaSn(OH) 6

Schoenfliesite, MgSn(OH)(6), and roxbyite, Cu1.72S, have been identified as products of corrosion of a 1375 BC bronze harpoon head from a shipwreck in the eastern Mediterranean Sea. The atomic structures of isostructural, synthetic schoenfliesite, burtite [CaSn(OH)(6)] and wickmanite [MnSn(OH)(6)] have been studied by neutron powder diffraction at 4 K. The results show that the hydrogen atoms are disordered over two positions in these cubic minerals. The bond lengths in the Sn(OH)(6) octahedra and polyhedron volumes for the three compounds are similar, and the octahedra exhibit a systematic change in angle variance. The bond lengths in the M(OH)(6) octahedra and polyhedron volumes change systematically with the increase in radius of the M cation.