Preparation and characterization of NaSm₉(SiO₄) ₆O₂ powders with infrared absorptive properties

NaSm₉(SiO₄)₆O₂ powders were synthesized by mild hydrothermal method at 180 °C for 24 h. The infrared optical properties and structure of the obtained powders were characterized. There existed two narrow and sharp absorptive bands near 943 cm^{- 1} (10.6 μm). The band at 938 cm^{- 1} was assigned to the stretching vibrations of SiOSm groups connecting to Q¹ species and the band at 989 cm^{- 1} was attributed to the stretching vibrations of SiOSm groups linking with Q⁰ species. The reflectivity was lower than 1% from 900 to 1200 nm and reached the minimum of 0.46% at 1073 nm. The prepared powders exhibit potential to act as a new kind of absorptive material for the infrared light of 10.6 μm and 1.06 μm.