Question : Which of the following species is not stable ?
(1) [SiF6]2- (2) [GeCl6]2-
(3) [Sn(OH)6]2- (4) [SiCl6]2-
answer : from all above options the correct answer is “(4) [SiCl6]2- ” because other three compounds are stable means [SiF6]2- , [GeCl6]2- and also [Sn(OH)6]2- is stable in nature but ‘[SiCl6]2- ‘ is unstable in nature that is we have marked this option for correct answer.
Answer explanation : Silicon can not form the complex [SiCl6]2- as size of silicon is smaller and due to steric hinderence , silicon can not bear six big Cl– ions. Hence the correct answer is option (4) that is [SiCl6]2- species is not stable.