How can we describe Selen,
this element is not plain.
Semiconductor or metal,
helpful or lethal?

Selen is a thermal allotrop,
which is different to an isotope.
Chemical ident but different in shape,
colour, confirmation, energy state.

It is toxic indeed,
but our body is in desperate need.
A so called trace element,
a certain dosis is excellent.

Mycrogramms only are required,
make sure you have what is desired.
For industry it had its prime,
but yet some spots for Selen to shine.

For manganese production a catalysator,
as alloying element in steel even more.
For some fancy glasses it is used as well,
thats probably all I can tell.

Selen, a catalysator for life,
decides about decay or strive.
In small amounts but still mandatory,
a complex element story.