Soddyite
The mineral Soddyit is a rarely occurring uranium mineral with the chemical composition (UO2 ) 2 ( SiO4) 2 • H2O. It crystallizes in the orthorhombic crystal system and developed both prismatic and pyramidal yellow crystals.
Special Features
The mineral is characterized by its uranium content of 71.25% highly radioactive and has a specific activity of more than 127.5 kBq / g (compared to natural potassium 0.0312 kBq / g).
Etymology and history
Soddyit 1922 was described by Alfred Schoep first time. He was at one stage an orange-brown crystals from the Curit Kasolo mine in Katanga ( now Democratic Republic of Congo) another, yellow mineral, for which he proposed the name " Soddite " in honor of the chemist Frederick Soddy, of the 1921 Nobel Prize for his work on the radioactive material and the nature of the isotope received. Billiet changed its name in 1926 to " Soddyit ", which was also accepted by Schoep and finally used in all of its other publications.
The type of mineral is located in the Natural History Museum in Paris.
Classification
The dated 8th edition of Strunz lists the Soddyit among the " island silicates with tetrahedral anions foreign " to the system no. VIII/B.36 and the only other member Swamboit.
The 9th, completely revised edition of Strunz lists the Soddyit in the Department K " uranyl island and layer silicates with a uranium: silicon ratio of U: Si = 2: 1" in the group 9.AK.05, where the Soddyit only representative of this group.
The commonly used in English-speaking classification of minerals according to Dana assigns the Soddyit in the group " Other Uranylsilikate " the Department of island silicates, there, however, in the department of " island silicates with SiO4 groups and other anions and complex cations with ( UO2) " with the System no. 53.03.03.01 one.
Education and Locations
Soddyit forms as a secondary uranium mineral in the oxidation zone of primary uranium ores. It is found as a silicate mineral associated with the other Uranylsilikaten Kasolit, Sklodowskit and uranophane. Furthermore, it is found in the classical association with the basic lead uranyl oxide Curit, as well as with the copper uranyl phosphate Torbernite. Sites are in addition to the type locality in Shinkolobwe ( Kasolo mine ) also Musonoi and Swambo mine in the Democratic Republic of Congo. In Germany it is known from the pit Krunkelbach in Menzenschwand and from Johann George Town and Tirpersdorf in Saxony. Furthermore, it was in the Radium Ridge in Australia, Lodève in France, Capo Terra in Italy, in Eger and Karlovy Vary in the Czech Republic, on Lake George in Canada, in Peña Blanca, Mexico, in Ust' - Uyuk in Russia, and be detected in Nevada and Wyoming in the United States.
Crystal structure
Soddyit crystallizes in the monoclinic space group P 21 with the lattice parameters a = 8.32 Å; b = 11.21 Å; c = 18.71 Å and eight formula units per unit cell. Soddyit is the only known Uranylmineral that a uranium - silicon has a ratio of 2:1. In the crystal structure of a tetrahedral silicate anion linked six pentagonal- bipyramidal uranyl ions. The uranyl polyhedra are edge-to here. The fifth equatorial coordination site is occupied by a water molecule here, whose hydrogen atoms build hydrogen bonds to the uranyl oxygen atoms. Through this linkage scheme creates a three-dimensional network.
Three-dimensional packaging structure of Soddyit in direction of the crystallographic c-axis
Precautions
Due to the strong radioactivity of the mineral should mineral samples from Soddyit in a dust - and radiation- tight containers are mainly but never kept in living, sleeping and working areas. Should be definitely prevented and the safety of direct body contact and worn when handling the mineral mask and gloves also because of the high toxicity and radioactivity of uranyl inclusion in the body ( incorporation, ingestion).