“…The space group C2/c is known for the LnAl 3 (BO 3 ) 4 with the Ln = Pr, Nd, Sm, Eu, Tb, Ho (the structure is refined, for example, in [97]); LnFe 3 (BO 3 ) 4 with the Ln = Nd; LnCr 3 (BO 3 ) 4 with the Ln = La, Pr, Nd, Sm, Tb, Dy, Ho; LnSc 3 (BO 3 ) 4 with the Ln = La, Ce, Pr ( Table 1). The centrosymmetry was determined by spectroscopic studies using a factor-group analysis of vibrations (for the LnAl 3 (BO 3 ) 4 with the Ln = Pr [42], Nd [42,45]; LnFe 3 (BO 3 ) 4 with the Ln = Nd [45]; LnCr 3 (BO 3 ) 4 with the Ln = La (Figure 10), Pr, Tb, Dy, Ho [70,71], Nd [26,45,70,71], Sm [70,72]). The LnSc 3 (BO 3 ) 4 crystals with the Ln = La, Ce, obtained by the Czochralski method, crystallize in the centrosymmetric space group C2/c), according to a study of their nonlinear optical properties [35].…”