A mixture of these elements can increase the heat resistance of nichrome alloys and is known as mischmetal.
A mixture of these elements can increase the heat resistance of nichrome alloys and is known as mischmetal. Many of these elements can be extracted from monazite. One of these elements was first synthesized at Oak Ridge in 1947, and does not naturally occur on Earth. Three of these elements were named after the town of (*) Ytterby. The ionic radii of these elements decrease across the period, which is known as its namesake "contraction." For 10 points, name this period of rare earth metals with atomic numbers fifty-seven to seventy-one, which lies above the actinides.
A mixture of these elements can increase the heat resistance of nichrome alloys and is known as mischmetal.
{lanthanides} [or {lanthanoids}; prompt on {rare earth metals}; prompt on {rare earth elements}]