Aluminium diboride is a chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 made from the metal aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 and the non-metal boron

Boron

Boron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid. Because boron is not produced by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth's crust. However, boron is concentrated on Earth by the...

. It is one of two compounds of aluminium and boron, the other being AlB₁₂

Aluminium dodecaboride

Aluminium dodecaboride is a chemical compound made from the metal aluminium and the non-metal boron. It is one of two chemical compounds that are commonly called aluminium boride, the other is aluminium diboride, AlB2. -Properties:...

 that are both commonly referred to as aluminium boride.

Structurally the B atoms form graphite

Graphite

The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω , "to draw/write", for its use in pencils, where it is commonly called lead . Unlike diamond , graphite is an electrical conductor, a semimetal...

 like sheets with Al atoms between them, and this is very similar to the structure of magnesium diboride

Magnesium diboride

Magnesium diboride is a simple ionic binary compound that has proven to be an inexpensive and useful superconducting material.Its superconductivity was announced in the journal Nature in March 2001. Its critical temperature of is the highest amongst conventional superconductors...

. Single crystals of AlB₂ exhibit metallic conductivity along the axis parallel to the basal hexagonal plane.

Aluminium boride is considered a hazardous substance as it reacts with acid

Acid

An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

s and hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

gas to produce toxic gases. For example, it reacts with hydrochloric acid to release borane and aluminium chloride.