Developing Intense Blue and Magenta Colors in α-LiZnBO3: The Role of 3d-Metal Substitution and Coordination.
We describe the synthesis, crystal structures, and optical absorption spectra/colors of 3d-transition-metal-substituted α-LiZnBO3derivatives: α-LiZn1-xMIIxBO3(MII=CoII(0<x<0.50), NiII(0<x≤0.05), CuII(0<x≤0.10)) and α-Li1+xZn1-2xMIIIxBO3(MIII=MnIII(0<x≤0.10), FeIII(0<x≤0.25)). The crystal structure of the host α-LiZnBO3, which is both disordered and distorted with respect to Li and Zn occupancies and coordination geometries, is largely retained in the derivatives, which gives rise to unique colors (blue for CoII, magenta for NiII, violet for CuII) that could be of significance for the development of new, inexpensive, and environmentally friendly pigment materials, particularly in the case of the blue pigments. Accordingly, this work identifies distorted tetrahedral MO4(M=Co, Ni, Cu) structural units, with a long M-O bond that results in trigonal bipyramidal geometry, as new chromophores for blue, magenta, and violet colors in a α-LiZnBO3host. From the L*a*b* color coordinates, we found that Co-substituted compounds have an intense blue color that is stronger than that of CoAl2O4and YIn0.90Mn0.10O3. The near-infrared (NIR) reflectance spectral studies indicate that these compounds exhibit a moderate IR reflectivity that could be significant for applications as "cool pigments".
Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India.
S
S
Tamilarasan
Materials Science and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, 695 019, India.
M L P
ML
Reddy
Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India.
S
S
Natarajan
Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India.
J
J
Gopalakrishnan
UV/Vis spectroscopy; blue pigments; dyes/pigments; magenta pigments; solid-state structures