ChemInform Abstract: Monoclinic LaGa_1‐xMn_xGe₂O₇: A New Blue Chromophore Based on Mn³⁺ in the Trigonal Bipyramidal Coordination with Longer Apical Bond Lengths.

Abstract

Lengths. -Blue pigments of LaGa 1-xMnxGe2O7 are prepared by firing La2O3, Ga2O3, Mn2O3, and GeO2 in stoichiometric amounts using H3BO3 as a flux (Pt crucible, 1100 C, 6 h). Substitution of Mn 3+ in LaGaGe2O7 changes the color from white (x = 0) to blue (x = 0.1-0.4) which is discussed in terms of the presence of a diminished symmetry-allowed transition at 1.7 eV and an increased symmetry-forbidden transition at 2.1 eV arising from prolonged Mn-O apical bonds. Temperature dependent magnetic susceptibility measurements reveal the presence of Mn 3+ along with Mn 4+ which also agrees with lattice parameter variations. -(SARASWATHY, D.; RAO*, P. P.; SAMEERA, S.; JAMES, V.; RAJ, A. K. V.; RSC Adv. 5 (2015) 35, 27278-27281, http://dx.