Imperator Crassus. Julius Caesar arrives at the House of Crassus and after a brief tussle with Crassus' guards, is welcomed by the man himself. Crassus strikes an alliance with Caesar in order to bring an end to Spartacus' rebellion. He orders Caesar to remain unshaven and the purpose of this is not revealed.
1 Lanthanum oxide additive to tungsten is used in gas tungsten arc welding electrodes, as a substitute for radioactive thorium. 2  Various compounds of lanthanum and other rare-earth elements (oxides, chlorides, etc.) are components of various catalysis, such as petroleum cracking catalysts.
There are 17 elements that are considered to be rare earth elementsâ15 elements in the lanthanide series and two additional elements that share similar chemical properties. They are listed below in order of atomic number (Z): Scandium or Sc (21). Scandium, a silvery-white metal, is a non-lanthanide rare earth.his silver-white metal is one of the most reactive rare earth elements. It is used to make special optical glasses, including infrared absorbing glass, camera and telescope lenses, and can also be used to make steel more malleable. Other applications for lanthanum include wastewater treatment and petroleum refining.