Metalloids are also known as “semi-metals”. They are found in the d block of the periodic table. In the d block, they are on the stair-step line that separates metals from non-metals. The line is drawn from the border of aluminum and boron to the border between polonium and astatine. Aluminum, however, is not a metalloid but a metal. Metalloids are called “semi-metals” because they have the properties of both metals and non-metals. Some of the metalloids are semi-conductors. Metalloids are better conductors of electricity than non-metals, and they conduct electricity more efficiently at higher temperatures. Many metalloids are used in the computer/electronics industries because of their capacity for conducting electricity. Some of the metalloids also possess a metallic luster. Usually metalloids establish covalent bonding when they are in compounds.