What Is The Crystal Structure Of Arsenic Tribromide?

Arsenic tribromide has a crystal structure that belongs to the orthorhombic crystal system with space group Cmcm. In this crystal structure, each arsenic atom is surrounded by three bromine atoms and each bromine atom is surrounded by two arsenic atoms.

The unit cell of the crystal structure contains four formula units of AsBr3 and is described by lattice parameters a = 8.462 Å, b = 9.688 Å, and c = 5.263 Å. The overall shape of the unit cell is elongated along the b-axis.

The molecular geometry of AsBr3 is trigonal pyramidal, with the arsenic atom at the apex and the three bromine atoms occupying the base of the pyramid. The bond lengths between the arsenic and bromine atoms are approximately 2.37 Å, while the Br-Br distances are around 4.13 Å.

Overall, the crystal structure of Arsenic tribromide exhibits a layered structure where the AsBr3 molecules are arranged in parallel layers along the c-axis and held together by weak van der Waals forces.