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In crystallography, atomic packing factor (APF), packing efficiency, or packing fraction is the fraction of volume in a crystal structure that is occupied by constituent particles. It is a dimensionless quantity and always less than unity. In atomic systems, by convention, the APF is determined by assuming that atoms are rigid spheres. The ...
Unit cell ball and stick model of arsenic triiodide: Names Preferred IUPAC name. ... AsI 3 Molar mass: 455.635 g/mol Appearance orange-red crystalline solid
The unit cell is defined as the smallest repeating unit having the full symmetry of the crystal structure. [2] The geometry of the unit cell is defined as a parallelepiped , providing six lattice parameters taken as the lengths of the cell edges ( a , b , c ) and the angles between them (α, β, γ).
A network model of a primitive cubic system The primitive and cubic close-packed (also known as face-centered cubic) unit cells In crystallography , the cubic (or isometric ) crystal system is a crystal system where the unit cell is in the shape of a cube .
[1] [2] Highest density is known only for 1, 2, 3, 8, and 24 dimensions. [3] Many crystal structures are based on a close-packing of a single kind of atom, or a close-packing of large ions with smaller ions filling the spaces between them. The cubic and hexagonal arrangements are very close to one another in energy, and it may be difficult to ...
The model shown to the left represents a ball-and-stick model of proline. The balls have colours: black represents carbon (C); red, oxygen (O); blue, nitrogen (N); and white, hydrogen (H). Each ball is drilled with as many holes as its conventional valence (C: 4; N: 3; O: 2; H: 1) directed towards the vertices of a tetrahedron. Single bonds are ...
In chemistry, ligand close packing theory (LCP theory), sometimes called the ligand close packing model describes how ligand – ligand repulsions affect the geometry around a central atom. [1] It has been developed by R. J. Gillespie and others from 1997 onwards [ 2 ] and is said to sit alongside VSEPR [ 1 ] which was originally developed by R ...
Very often, cis–trans stereoisomers contain double bonds or ring structures. In both cases the rotation of bonds is restricted or prevented. [4] When the substituent groups are oriented in the same direction, the diastereomer is referred to as cis, whereas when the substituents are oriented in opposing directions, the diastereomer is referred to as trans.