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
Hospital in Arles ""Souvenirs de la maison des morts" ("Memories of the House of the Dead"). Vincent described the painting to his sister Wil, "In the foreground a big black stove around which some grey and black forms of patients and then behind the very long ward paved in red with the two rows of white beds, the partitions white, but a lilac- or green-white, and the windows with pink curtains, with green curtains, and in the background two figures of nuns in black and white. The ceiling is violet with large beams." Debra Mancoff, author of "Van Gogh's Flowers," comments, "In his