Lumiflavin forms orange crystals upon recrystallisation from 12% aqueous AcOH, or from formic acid. It sublimes at high vacuum. It is freely soluble in CHCl3, but not very soluble in H2O and most organic solvents. In H2O and CHCl3 solution it has a green fluorescence. UV has max at 269, 355 and 445nm ( 38,800, 11,700 and 11,800, respectively) in 0.1N NaOH and 264, 373 and 440nm ( 34,700, 11,400 and 10,400, respectively) in 0.1N HCl, while the UV in CHCl3 has max at 270, 312, 341, 360, 420, 445 and 470nm. [Hemmerich et al. Helv Chim Acta 39 1242 1956, Holiday & Stern Chem Ber 67 1352 1834, Yoneda et al. Chem Pharm Bull Jpn 20 1832 1972, Birch & Moye J Chem Soc 2622 1958, Fluorescence: Kuhn & Moruzzi Chem Ber 67 888 1934, Beilstein 26 III/IV 2539.]
