Abstract: To provide an optical glass having the optical characteristics of a high refractive index and low dispersion, and moreover, which makes it possible to further reduce devitrification and which can be stably obtained, and a preform and an optical element using the same. The optical glass comprises, expressed in cation % (mol %), 17.0% to 42.0% of P5+, 7.0% to 30.0% of Al3+, more than 0% to 22.0% of Mg2+, more than 0% to 25.0% Ca2+, more than 0% to 30.0% of Sr2+, more than 0% to 35.0% Ba2+, and expressed in anion % (mol %), a content ratio of F? of 37.0 to 64.0%, a content ratio of O2? of 36.0 to 63.0%, a refractive index (nd) of 1.48 to 1.58, and having an Abbe number (vd) of 70 to 88, and a liquidus temperature of 800° C. or less.

Abstract: To provide an optical glass having the optical characteristics of a high refractive index and low dispersion, and moreover, which makes it possible to further reduce devitrification and which can be stably obtained, and a preform and an optical element using the same. The optical glass comprises, expressed in cation % (mol %), 17.0% to 42.0% of P5+, 7.0% to 30.0% of Al3+, more than 0% to 22.0% of Mg2+, more than 0% to 25.0% Ca2+, more than 0% to 30.0% of Sr2+, more than 0% to 35.0% Ba2+, and expressed in anion % (mol %), a content ratio of F? of 37.0 to 64.0%, a content ratio of O2? of 36.0 to 63.0%, a refractive index (nd) of 1.48 to 1.58, and having an Abbe number (vd) of 70 to 88, and a liquidus temperature of 800° C. or less.

Abstract: Provided is glass having a predetermined index of refraction (nd) and Abbe number (?d), high chemical resistance (acid resistance) and a small degree of abrasion. The optical glass contains, in wt %, 10.0-40.0% of a SiO2 component, 15.0-50.0% of a La2O3 component and 5.0% to less than 25.0% of a TiO2 component, has a mass ratio B2O3/SiO2 less than or equal to 1.00, an index of refraction (nd) of 1.78-1.95 and an Abbe number (?d) of 25-45, and chemical resistance (acid resistance) via a powder method that is class 1-3. The optical glass has a degree of abrasion of less than or equal to 200.