Why isn't there a lot of evidence for the properties of francium?

Because Francium is so highly radioactive, it disintegrates before it can be collected. The half-life of the least stable isotope of Francium, Francium-215, is a mere 86 nanoseconds. The half-life of the most stable isotope of Francium, Francium-223, is still only 22 minutes. Scientists cannot gather Francium from nature due to the fact that even if they do come across some, it will soon disintegrate into other elements like barium. If scientists want to study Francium, they must make Francium atoms in a laboratory.