They are hard solid with a crystal lattice structure... with high melting points
X element can give 3 electrons, and ions X³⁺ can be formed.
Phosphate ion - (PO4)³⁻,
So compound will have formula X³⁺(PO4)³⁻,
XPO4
The electron subshells in the atoms of group 5a elements discourage electron addition.
This is because the subshells in the group 5a elements are already half-filled, which is a more stable electronic configuration that that which would be achieved if another electron was added.
Meanwhile, group 4a elements' subshell becomes half-filled when an electron is added, making them somewhat stable. This means that they prefer electron addition.