http://www.w3.org/ns/prov#value | - Titanium is found in column four along with chemically similar zirconium, hafnium, and thorium.For most of history, hafnium and zirconium were not clearly distinguished from each other.Samarium is a rare earth element, one of the elements that occupy the space in Row 6 of the periodic table between lanthanum and hafnium.
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