Allotropes of phosphorus Allotropes of phosphorus Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and atomic phosphorus. White phosphorus, yellow phosphorus or simply tetraphosphorus (P) exists as molecules made up of four atoms in a tetrahedral structure. The tetrahedral arrangement results in ring strain and instability. The molecule is described as consisting of six single P–P bonds. Two different crystalline forms are known. The α form is defined as the standard state of the element, but is actually metastable under standard
Violet (color) sense for any color between blue and red). In color theory, a purple is a color along the line of purples on the CIE chromaticity diagram and excludes violet. Violet light from the rainbow, which can be referred as spectral violet, has only short wavelengths. Violet objects are objects that reflect violet light. Objects reflecting spectral violet often appear dark, because human vision is relatively insensitive to those wavelengths. Monochromatic lamps emitting spectral-violet wavelengths can be roughly approximated by the color shown below as "electric violet". The earliest violet pigments used by humans, found in prehistoric cave paintings, were made