Chemically strengthened glass, and glass for chemical strengthening

A chemically strengthened glass sheet, comprising a glass which comprises, in mole percentage on an oxide basis, 58 to 72% of SiO2, 13 to 18% of Al2O3, 0 to 5% of B2O3, 0.5 to 4% of P2O5, 4 to 13% of Li2O, 7 to 14% of Na2O, 0 to 2% of K2O, 0 to 11% of MgO, 0 to 14% of CaO, 0 to 12% of SrO, 0 to 15% of BaO, 0 to 10% of ZnO, 0 to 1% of TiO2, and 0 to 2% of ZrO2, wherein:

• the chemically strengthened glass sheet has a surface compressive stress (CS) of 450 MPa or more;
• a compressive stress value (CS90) in a portion at a depth of 90 μm from a surface of the chemically strengthened glass sheet is 25 MPa or more, or a compressive stress value (CS100) in a portion at a depth of 100 μm from the surface is 15 MPa or more;
• a depth dh of a portion at which a magnitude of an internal compressive stress of the chemically strengthened glass sheet reaches ½ of a surface compressive stress (CS) of the chemically strengthened glass sheet is 30 μm or less;
• and
• a value of X is 30000 or more, the value of X being calculated based on the following formula by using contents in mole percentage on an oxide basis of components of SiO2, Al2O3, B2O3, P2O5, Li2O, Na2O, K2O, MgO, CaO, SrO, BaO, and ZrO2:
• X=SiO2×329+Al2O3×786+B2O3×627+P2O5×(−941)+Li2O×927+Na2O×47.5+K2O×(−371)+MgO×1230+CaO×1154+SrO×733+ZrO2×51.8.