The two hydrogens of the water molecule can form hydrogen bonds with other oxygens in water, and the two lone pair of electrons on oxygen of the water molecule can attract other hydrogens in water. Hence, 4 possible hydrogen bonds.
So XeF2 has the maximum no. of lone pairs associated with Xe.
In IF7 out of 7 Flourine atoms 5 of them are placed on a plane in Pentagon shape. In remaining 2 flourines one is placed above the plane and other below the plane each at 90 degrees
CaC2 has a combination of bonds. It is an ionic lattice that has Ca2+ cations and acetylide C22- anions. Within each C22-there is a triple bond between the 2C atoms, consisting of 1 sigma and 2 pi bonds.
Few ionic bonds have partial covalent characteristics which were first discussed by a scientist, Kazimierz Fajans in 1923. He gave the rule to predict whether a chemical bond will be covalent or ionic which is now commonly known as Fajan’s rule. The rule can be stated as:
Keeping these rules in mind, we can say that AlCl3 has high covalent character.
In sp3d2 Hybridization one s, three p and two d-orbitals get hybridized to form six sp3d2 hybrid orbitals which adopt octahedral arrangement as given in image below