Final answer:
The AXE description for the borate (BO3 3-) anion is AX3, indicating a central boron atom with three oxygen atoms and no lone pairs, resulting in a trigonal planar geometry and sp² hybridization.
Step-by-step explanation:
The "AXE" description for the borate (BO3 3-) anion is AX3. This description arises from considering the boron atom (B) as the central atom (A), surrounded by three oxygen atoms (X), with no lone pairs of electrons on the boron atom (E). The geometry of the BO3 3- anion is trigonal planar, which means that the three oxygen atoms are positioned at the corners of an equilateral triangle with the boron atom in the center. The boron in BO3 3- is sp² hybridized, resulting in the planar structure observed.
Similar to borates, boron trifluoride (BF3) also has a central boron atom with an incomplete octet and is associated with the trigonal planar molecular geometry. In various borates, such as those found in commercial products like borax, the borate anions may form chains and rings with three- and four-coordinated boron atoms.