The negative electrode material has a reaction phase including an element capable of producing an intermetallic compound with Li, and C. Preferably, the reaction phase has the half width of diffraction peak by X-ray diffraction of not smaller than 0.5˚.

With the phosphor mixture, the emission intensity of the maximum emission peak of the emitted light is higher than that of the phosphor (A), and the half width of the maximum emission peak of the emitted light is greater than that of the phosphor (B).

The molar fractions x, y and z, the dopant species and the dopant concentration may be varied to tune the peak emission wavelength and/or the width of the emission peak.

The mass peak of the new state, called X(5568), is relatively broad (22 MeV) indicating that the particle decays via the strong interaction.

The half width of the peak in the first position is 3.2 degrees or less, and that in the second position is 2.6 degrees or less.