Which of the following statement(s) is/are false?

P. Boron and Gallium form BF₆^3- ions. Q. Alclad is the alloy of aluminium used in the formation of corrosion resistant sheet. R. Boron fibres are used in making bullet-proof vest and light composite material for aircraft.

P. Due to non-availability of d orbitals, boron is unable to expand its octet. Therefore, the maximum covalence of boron cannot exceed 4. Al, Ga, In and Tl have vacant d orbitals and form such type of ions. Q. Alclad is a trademark of Alcoa used as a generic term to describe corrosion-resistant aluminium sheet formed from high-purity aluminium surface layers metallurgically bonded to high-strength aluminium alloy core material. R. Boron fiber exhibits a unique combination of high strength, high modulus and large diameter. Boron fibres are used in making bullet-proof vest and light composite material for aircraft.