Transition Metals: Periods 6 & 7

The heavier transition metals in periods 6 and 7 include some of the most valuable, durable, and — in the case of period 7 — most recently discovered elements in the periodic table. Period 6 contains metals prized since antiquity, while period 7 features superheavy elements created only in particle accelerators.

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Period 6 Transition Metals

Element	Symbol	Atomic Number	Key Feature
Hafnium	Hf	72	Nuclear reactor control rods
Tantalum	Ta	73	Capacitors in electronics
Tungsten	W	74	Highest melting point of all metals
Rhenium	Re	75	Jet engine superalloys
Osmium	Os	76	Densest naturally occurring element
Iridium	Ir	77	Hardest platinum group metal
Platinum	Pt	78	Catalysis, jewellery
Gold	Au	79	Most malleable metal
Mercury	Hg	80	Only metal liquid at room temperature

Hafnium (Hf, Z = 72)