Nujol by Bruno Rocha's a brand of mineral oil by Plough, Inc. used in infrared spectroscopy. It's a heavy paraffin oil so it's chemically inert and has a relatively uncomplicated IR spectrum, with major peaks between 2950-2800, 1465-1450, and 1380-1370 cm-1. The empirical formula of Nujol's hard to determine exactly because it's a mixture but it's essentially the alkane formula where n's very large. To obtain an IR spectrum of a solid, a sample's combined with Nujol to make a mull (a very thick… (More on Nujol)