Fig. 1From: A novel Brönsted–Lewis acidic heteropoly organic–inorganic salt: preparation and catalysis for rosin dimerizationFT-IR spectra for hybrid catalysts. a Sm0.33[TEAPS]2PW12O40. b Reused Sm0.33[TEAPS]2PW12O40. c H2[TEAPS]PW12O40. d H3PW12O40 Back to article page