phosphorus

A highly reactive, poisonous, nonmetallic element occurring naturally in phosphates, especially apatite, and existing in three allotropic forms, white (or sometimes yellow), red, and black (or violet). An essential constituent of protoplasm, it is used in safety matches, pyrotechnics, incendiary shells, and fertilizers and to protect metal surfaces from corrosion. Atomic number 15; atomic weight 30.9738; melting point (white) 44.15°C; boiling point 280.5°C; specific gravity (white) 1.82, (red) 2.16, (black) 2.25 to 2.69; valence 3, 4, 5. cross-reference: Periodic Table.

A phosphorescent substance.

[With a pl. phosphori (-rī).] In early use, a substance which emits light otherwise than as the result of ordinary combustion.

[capitalized] The morning star; Phosphor.

Chemical symbol, P; atomic weight, 31; specific gravity, 1.826. A solid non-metallic combustible substance, hitherto undecomposed, not found by itself in nature, but occurring chiefly in combination with oxygen, calcium, and magnesium.

A small bottle containing 12 grains of phosphorus melted in half an ounce of olive-oil. On being uncorked in the dark this solution emits light enough to illuminate the dial of a watch, and it will retain this property for several years if not too frequently used.

The morning star; Phosphor.

A poisonous nonmetallic element of the nitrogen group, obtained as a white, or yellowish, translucent waxy substance, having a characteristic disagreeable smell; this waxy allotropic form is also called yellow phosphorus, to distinguish it from another allotropic form, red phosphorus. It is very active chemically, must be preserved under water, and unites with oxygen even at ordinary temperatures, giving a faint glow, — whence its name. It always occurs combined, usually in phosphates, as in the mineral apatite, in bones, etc. It is used in the composition on the tips of friction matches, and for many other purposes. The molecule contains four atoms. Symbol P. Atomic weight 31.0.

Hence, any substance which shines in the dark like phosphorus, as certain phosphorescent bodies.