Clearly it is not a bravais lattice in a bravais lattice the lattice must look exactly the same when viewed from any lattice point it can be thought of as a bravais lattice with a basis consisting of more than just one atom per lattice point two atoms in this case.
													
																	Describe this structure as a attice and a basis. 
									
	
		
	
																	3 8 from kittel the crystal structure is formed by the addition of the basis b to the lattice points of the lattice a. 
																	Conventional or prescriptive construction practices are based as much on experience as on technical analysis and theory. 
																	A lattice is a hypothetical regular and periodic arrangement of points in space. 
																	The basis is a set of atoms which is located near each site of a bravais lattice. 
															
													
									
	
		
	
																	This generates a structure that is referred to as a crystal a crystalis defined as a latticewith a basisadded to each lattice site. 
																	When incorporated into a building code prescriptive sometimes called cookbook construction requirements can be easily followed by a builder and inspected by a code official without the services of a design professional. 
																	By looking at c you can recognize the basis and then you can abstract the space lattice. 
																	A basis is a collection of atoms in particular fixed arrangement in space. 
															
													
									
	
		
	
																	An atom or a group of atoms associated with each lattice point in crystal. 
																	1 diamond structure fig. 
																	Thus in fig 2 the basis is represented by the two atoms a and a1. 
																	The lattice is defined by fundamental translation vectors. 
															
													
									
	
		
	
																	Lets see how a two dimensional lattice may look. 
																	Translationally periodic arrangement of atoms in space. 
																	It is used to describe the structure of a crystal. 
																	It does not matter where the basis is put in relation to a lattice point. 
															
													
									
	
		
	
																	Translationally periodic arrangement of points in space. 
																	In a general case crystal structure can be considered as crystal structure lattice basis. 
																	This classification is based on the kind of atoms present in the face within a lattice structure. 
																	Usually the basis consists of an atom a group of atoms or a molecule.