Patent ID: 7431911

Claim:
A barium titanate comprising at least one element selected from the group consisting of Sn, Zr, Ca, Sr, Pb, La, Ce, Mg, Bi, Ni, Al, Si, Zn, B, Nb, W, Mn, Fe, Cu, and Dy, said at least one element being in an amount of less than about 5 mol %, inclusive of 0 mol %, on the basis of the entirety of BaTiO3, wherein BET specific surface area x, unit: m 2 /g, and the ratio y of the c-axis length, unit: nm, of a crystal unit lattice to the a-axis length, unit: nm, of the crystal unit lattice as measured by means of a Rietveld method satisfy one of the following two relations (1) and (2): (1) y≧1.01−(8.8)(10 −6 )(x 3 ), wherein x is greater than about 0.1 and not more than 9.7 (2) y≧1.003 and x>9.7.