Magnesium sulfate constituents of evaporitic potassium-magnesium (K-Mg) salts deposits. Bright spots observed by the Dawn Spacecraft in Occator Crater on the dwarf planet Ceres are most consistent with reflected light from magnesium sulfate hexahydrate. Almost all known mineralogical forms of MgSO are hydrates. Epsomite is the natural analogue of "Epsom salt". Another heptahydrate, the copper-containing mineral alpersite (Mg,Cu)SO·7HO, was recently recognized. Both are, however, not the highest known hydrates of MgSO, due to the recent terrestrial find of meridianiite, MgSO·11HO, which is thought to also occur on Mars. Hexahydrite is the next lower (6) hydrate. Three next lower hydrates—pentahydrite, starkeyite, and especially
Magnesium iron hexahydride Magnesium iron hexahydride Magnesium iron hexahydride is an inorganic compound with the formula MgFeH. It is a green diamagnetic solid that is stable in dry air. The material is prepared by heating a mixture of powdered magnesium and iron under high pressures of hydrogen: The compound is isomorphous with KPtCl, i.e., their connectivities and structures are the same. The [FeH] centre adopts octahedral molecular geometry with Fe-H distances of 1.56 Å. The Mg centres are bound to the faces of the octahedron, with Mg-H distances of 2.38 Å. Several related compounds are known including salts of [RuH], [OsH], and [PtH]