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Two iron−chromate precipitates, KFe3(CrO4)2(OH)6 (the chromate analog of the sulfate mineral jarosite) and KFe(CrO4)2·2H2O, were discovered in a soil contaminated by chrome plating solutions. The precipitates were identified by electron microscopy and powder X-ray diffraction. KFe3(CrO4)2(OH)6 was found as small crystals interspersed within the bulk soil. KFe(CrO4)2·2H2O forms crusts in cracks and fractures of the soil. Powder X-ray diffraction of the whole soil indicates that most of the Cr(VI) in the soil is present as KFe3(CrO4)2(OH)6 and that the overall amount of KFe(CrO4)2·2H2O in the soil is relatively small. The reaction for the transformation between these two phases indicates that KFe(CrO4)2·2H2O is likely to form in more acidic , K+- and HCrO4 --rich environments than KFe3(CrO4)2(OH)6. Although both of these chromate phases have been synthesized and described, to our knowledge, this study is the first report of their occurrence in the environment.

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Nd-Fe-B and Sm-Co permanent magnets have been irradiated with fission neutrons and gamma rays. Irradiated samples were periodically removed for room temperature measurements of the open-circuit remanence. Hysteresis loops were measured before and after irradiation. For neutron irradiation, two Nd-Fe-B magnets showed a rapid loss of remanence, while a third magnet from another manufacturer decayed more slowly, suggesting that the radiation hardness of Nd-Fe-B magnets may depend on microstructural details. Irradiation in the Omega West Reactor at Los Alamos with fast neutrons caused the fast-decay samples to have an Wtial loss of remanence of 1% for irradiation at 350 K to a fluence of 1015 n/cm2. Both SmCo5 and Sm2Co17 magnets showed excellent resistance to radiatifg-induied loss of remanence for neutron irradiation to a fluence of 2.6×1018 n/cm2. Results for gamma radiation showed no loss of remanence for a dose of about 49 Mrad using a 60Co source. Possible mechanisms for radiation-induced loss of magnetic properties are discussed.