What type of crystal defects is indicated in the diagram given below ?
` {:(Na""^(+)C^(21),Na""^(+)Cl^(-),Na""^(+)Cl^(-)),(Cl^(-)square,square Cl^(-),Na""^(+)Cl^(-)),(Cl^(-)Na^(+),Cl^(-)Na^(+),Na^(+)square):}`