The halogens exist, at room temperature, in all three states of matter - Gases such as Fluorine & Chlorine, Solids such as Iodine and Astatine and Liquid as in Bromine.

Brief Facts about the Discovery and History of the Element Astatine
Astatine was discovered in University of California, Berkeley, USA by Dale R. Corson, K. R. MacKenzie, and Emilio Segre in 1940.

Occurrence of the element Astatine in the Atmosphere
The total amount of astatine in Earth's crust is estimated to be less than 1 oz (28 g) at any one time

Common Uses of Astatine
None. Astatine is studied by nuclear scientists. Its high radioactivity requires special handling techniques and precautions. Its toxicity is similar to that of iodine.

The Properties of the Element Astatine
Name of Element : Astatine
Symbol of Element : At
Atomic Number of Astatine : 85
Atomic Mass: (210.0) amu
Melting Point: 302.0 °C - 575.15 °K
Boiling Point: 337.0 °C - 610.15 °K
Number of Protons/Electrons in Astatine : 85
Number of Neutrons in Astatine : 125
Crystal Structure: Unknown
Density Unknown
Color of Astatine : Unknown