描述
Lanthanum, also known as 57la or lantano, is a member of the class of compounds known as homogeneous lanthanide compounds. Homogeneous lanthanide compounds are inorganic compounds containing only metal atoms, with the largest atom being a lanthanide atom. Lanthanum can be found in a number of food items such as garden tomato, dill, broccoli, and almond, which makes lanthanum a potential biomarker for the consumption of these food products. Lanthanum is a chemical element with symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. It is also sometimes considered the first element of the 6th-period transition metals and is traditionally counted among the rare earth elements. The usual oxidation state is +3. Lanthanum has no biological role in humans but is essential to some bacteria. It is not particularly toxic to humans but does show some antimicrobial activity .