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It has an unusual polymeric construction with helical chains, where the protactinium atom has coordination number of 12 and is surrounded by six BH4− ions. Another organometallic complicated is the golden-yellow bis(π-cyclooctatetraene) protactinium, or protactinocene (Pa(C8H8)2), which is analogous in construction to uranocene. Protactinium(IV) varieties a tetrahedral complex tetrakis(cyclopentadienyl)protactinium(IV) (or Pa(C5H5)4) with four cyclopentadienyl rings, which may be synthesized by reacting protactinium(IV) chloride with molten Be(C5H5)2.



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> Just like uranocene, it may be prepared by reacting protactinium tetrachloride with dipotassium cyclooctatetraenide (K2C8H8) in tetrahydrofuran. Meitner than chose the name protactinium. The prefix "eka" is derived from the Sanskrit एक, that means "one" or "first." In chemistry, it was previously used to indicate an element one period below the element title following it. The concentration evaluation for both protactinium-231 (half-life 32,760 years) and ezigarettenliquid 230Th (half-life 75,380 years) improves measurement accuracy in comparison with when just one isotope is measured; this double-isotope method can be weakly delicate to inhomogeneities within the spatial distribution of the isotopes and to variations in their precipitation charge.