In Boylestad and Nashelsky's Electronic Devices and Circuit Theory, the structure of GaAs is shown as follows:
Arsenic is shown making five covalent bonds to neighbouring gallium atoms.
However, I recently also saw an alternative depiction in Razeghi's Fundamentals of Solid State Engineering:
Here, arsenic is shown making four covalent bonds to neighbouring gallium.
Which source is correct? Please give appropriate references or experimental proof.