“…Crystals grown within 1050 C±1100 C by slow cooling (1±2 C/day) obtained dimensions of 7´7´3 mm 3 and were reported to be of good optical quality. [101,102] The potential NLO borate Ca 5 (BO 3 ) 3 F with isolated [BO 3 ] triangles as NLO-active groups and monoclinic space group symmetry Cm [103] is only grown as small crystals by the flux method from a melt containing CaCO 3 , H 3 BO 3 , and CaF 2 , but no further details are reported. [103] The family of the pyroborates ANbOB 2 O 5 , with A = K, Rb, Cs, crystallizing in Pna2 1 (for A = K) [104,105] and Pnm2 1 (for A = Rb, [106] Cs [107] ) [104] to 8 C/day, [105] resulting in crystal sizes up to 8´10´3 mm 3 for RbNbOB 2 O 5 and 2´2´5 mm 3 for KNbOB 2 O 5 .…”