Antimony is a semi metallic chemical element which can exist in two forms: the metallic form is bright, silvery, hard and brittle; the non metallic form is a grey powder. Antimony is a poor conductor of heat and electricity, it is stable in dry air and is not attacked by dilute acids or alkalis. Antimony and some of its alloys expand on cooling. Antimony has been known since ancient times. It is sometimes found free in nature, but is usually obtained from the ores stibnite (Sb2S3) and valentinite (Sb2O3). Nicolas Lemery, a French chemist, was the first person to scientifically study antimony and its compounds. He published his findings in 1707. Antimony makes up about 0.00002% of the earth's crust.