No abstract

Uranylamid(I) entsteht in flüssigem Ammoniak nach der Gleichung:K[UO2(NO3)3] + 2 KNH2 → UO2(NH2)2 + 3 KNO3 als unlöslicher, röntgenamorpher Niederschlag. Es reagiert in flüssigem Ammoniak mit NH4J und KNH2 unter Bildung der Salze UO2(NH3)2J2 (II) bzw. UO2(NH)2K2 (III) (amphoteres Verhalten). Der thermische Abbau von (I) im Autoclaven unter NH3‐Druck führt zunächst zu Uranylimid UO2NH (IV), das sich bei höherer Temperatur zu mikrokristallinem UO2 unter Abgabe von NH3 und N2 zersetzt. Der thermische Abbau von (III) ergibt das Nitridosalz (UO2)3N4K6 (V). (V) beginnt bei etwa 170° in metall. Kalium, N2 und UO2 zu zerfallen; Beendigung des Zerfalles bei 380°. (III), (IV) und (V) sind röntgenamorphe Stoffe (Flüssigkeitsdiagramme).

ABSTRACT/High indoor radon concentrations in a uraniumradium low-level area in the Eifel region, Germany, near the village of DOttingen are caused by ascending radon migration following the convection of groundwater and soil gas along pathways (fractures and faults) in the bedrock sediments of Lower Devonian age. Positive radon anomalies in the soil gas are found to coincide with the locations of houses showing the highest concentrations. These houses are older buildings without concrete foundation slabs. Normally radon concentrations in soil gas are highly correlated with the values of emanated radon calculated on the basis of radium content in the surrounding soils and rocks (diffusive radon potential). However, close to zones of tectonic fractures and faults around the maar-type volcano of D6ttingen abnormally high radon concentrations, which were transported by circulating groundwater and postvolcanic exhalation of CO 2 (convective radon potential) were detected.