CompuServe Messages

Doug, The hypophosphite ion is H2PO2-, with the other two hydrogens being bound directly to the phosphorous. I would presume it would be stable inside of solid crystals, but it air-oxidizes very rapidly. If I cracked open a rock and found a garlic smell, I would suspect arsenic or phosphorous all right. These ions form as minerals when superheated water under pressure is reduced by contact with low-oxidization species (usually iron) forming dissolved hydrogen. Typically, the iron is present as iron carbides, and is present in blueschist facies in subduction zones. The water (steam – remember, it's a superfluid under pressure, and comes from the water of hydration of subducted minerals. The hydrogen can generate reduced metals and metaloids, and even reduced phosphate species. Farther up towards the surface, the hydrogen can reduce sulfate minerals to hydrogen sulfide. The hydrogen sulfide breaks down at the surface of the vents, and deposits elemental sulfur. A good place to obtain samples of hyperreduced minerals is from carbonatites brought up in oil well cores, or from the bottom metamorphic facies of anthracite coal seams. If you smell a sulfur-containing well core, you can distinctly smell hydrogen sulfide. Sulfur itself does not give off this odor, so you can be certain that there are reduced species in the limestone, which can include calcium and magnesium hydrosulfides. Cores from the Gulf of Mexico sometimes include phosphoapatite seams, and it is within these seams that you can find the hypophosphite minerals, usually as contact metamorphism between the phosphates and the carbonatite matrix. It's very visible in thin section. Even though the processing (wet grinding) destroys the hypophosphites, the crystal structure remains. — Norm