History
The discovery of all elements in the group led to controversies. The verification of those discoveries was difficult due to similarity of vanadium and group 6 element chromium, the chemical similarity of niobium and tantalum and the complicated setup which was necessary to produce a few atoms of dubnium.
Read more about this topic: Group 5 Element
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“Every library should try to be complete on something, if it were only the history of pinheads.”
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—Ben C. Bradlee (b. 1921)