Slow moving neutrons.
The nuclear reactions are:
23892U + n-------23992U-------23993Np + e--------23994Pu + e
One of the elements that can be formed by bombarding uranium with deuterium is neptunium-237. This process involves the nuclear reaction wherein a uranium-238 nucleus captures a deuterium nucleus, leading to the formation of neptunium-237.
Assuming you mean man[made], no. Trace amounts of neptunium are found in uranium ores in Nature.
Neptunium and plutonium are derived from uranium by nuclear reactions.
Before uranium is protactinium. After uranium is neptunium.
Uranium is more common and useful.
Chemical symbols of: Mercury - Hg Uranium - U Plutonium - Pu Neptunium - Np
Neptunium is an artificial chemical element; in the nature infinitesimal amounts of neptunium are possible in uranium ores.
Neptunium (Np)
Uranium,Plutonium,Neptunium
Neptunium has not minerals. It is an artificial element and in the nature is very rare, in some uranium ores.
Neptunium is an artificial chemical element but neptunium can be found also in the nature as a result of decay processes in uranium ores, only in ultratraces.
Neptunium is a solid metal, radioactive, man made (naturally exist only in very low concentrations in uranium ores), many isotopes are known (the most important is neptunium-237), etc. See also the link below for details.