| The first period of rare earths research (end of 18th and beginning of 19th centuries) the names of rare earths and their minerals were very confusing. Thus the mineral found in Ytterby, a village on the Swedish island of Resaro and named ytterbite had been renamed in gadolinite after Johan Gadolin& |
Lanthanide Lanthanum crustal abundance is 2.9x10-3 mass %., in sea water 2.9x10-6 mg/L. Along with other rare earth elements it is contained in monazite, bastnasite, loparite and in apatite. These minerals are the main source from which Lanthanum may be took out.
Total crustal abundance of lanthanum and lanthanides is estimated to be 1.78x10-2 mass % and is bigger for lanthanides with even numbers. Lanthanides are characteristic elements for Earth crust; their quantities in mantle and meteorites are negligible. Magmatic processes accumulate lanthanides in granitoids and in alkali rocks. Lanthanum forms 9 minerals and cerium 33; other lanthanides make isomorphous in crystal grids of other minerals, mostly those of rare earth elements. In many minerals lanthanides isomorpically substitute calcium, uranium, terbium etc. Lanthanum is poorly mobile in biosphere under most environmental conditions. Data on their migration in are scarce. Some thermal deposits of phosphates, fluorocarbonates and lanthanum fluorides are known; however the most important of them are the complex deposits associated with alkali magmatic rocks and carbonatites as well as deposits of sedimentary phosphorites, alkali rocks residual soil, littoral and alluvial placers of xenotime and monazite. |