The debye (symbol: D) is a non-SI, CGS unit of electrical dipole moment. The centimetre-gram-second system ( CGS) is a system of physical units. In Physics, the electric dipole moment (or electric dipole for short is a measure of the polarity of a system of Electric charges. It is defined as 1×10−18 statcoulomb centimeter (or 1×10−20 esu m, or 1×10−18 Fr cm). The statcoulomb ( statC) or franklin ( Fr) or electrostatic unit of charge ( esu) is the physical unit for Electrical The statcoulomb ( statC) or franklin ( Fr) or electrostatic unit of charge ( esu) is the physical unit for Electrical In SI units, 1 D equals approximately 3. 33564×10−30 coulomb-meter (exactly 1×10−21 C m2/s divided by c, the speed of light in vacuum). The coulomb (symbol C) is the SI unit of Electric charge. It is named after Charles-Augustin de Coulomb. The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International Conversely 1 C m = 2. 9979×1029 D. It is named after the physicist Peter J. W. Debye. Peter Joseph William Debye ( March 24 1884 &ndash November 2 1966) was a Dutch physicist and physical chemist
Historically the debye was defined as the dipole moment resulting from two charges of opposite sign but an equal magnitude of 10-10 statcoulomb (generally called esu in older literature), which were separated by 1 angstrom (10-8 cm or 10-10m). The statcoulomb ( statC) or franklin ( Fr) or electrostatic unit of charge ( esu) is the physical unit for Electrical An ångström or angstrom (symbol Å) (ˈɔːŋstrəm Swedish: ˈɔ̀ŋstrœm is an internationally recognized non- SI unit of length equal
Note that 10-10 statcoulomb is 0. The statcoulomb ( statC) or franklin ( Fr) or electrostatic unit of charge ( esu) is the physical unit for Electrical 48 units of elementary charge.
This gave a convenient unit for molecular dipole moments. Typical dipole moments for simple diatomic molecules are in the range of 0 - 11D, where symmetric homoatomic species, e. g. chlorine, Cl2, have a dipole moment of 0D and highly ionic molecular species such as gas phase potassium bromide, KBr have a dipole moment of 10. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and Potassium bromide ( K[[Bromine Br]] is a salt, widely used as an Anticonvulsant and a Sedative in the late 19th and early 20th centuries 5D. 
The debye is still used in atomic physics and chemistry because SI units are inconveniently large, particularly since the smallest prefix is ×10−24 (e. Atomic physics (or atom physics) is the field of Physics that studies atoms as an isolated system of Electrons and an atomic nucleus. Chemistry (from Egyptian kēme (chem meaning "earth") is the Science concerned with the composition structure and properties g. , 2. 54 D = 8. 47×10−6 yCm). yocto- (symbol y) is an SI prefix in the SI system of units denoting a factor of 10−24 or 0 Note that SI disallows the application of prefixes to both members of a compound unit (e. g. , 2. 54 D = 8. 47 fC·fm) or the compounding of prefixes (e. femto- is an SI prefix (symbol f) in the SI system of units denoting a factor of 10−15 or 0 g. , 2. 54 D = 8. 47 µyCm), so there is currently no satisfactory solution to this problem of notation. micro- ( µ) is a prefix in the SI and other systems of units denoting a factor of 10&minus6 (one Millionth. yocto- (symbol y) is an SI prefix in the SI system of units denoting a factor of 10−24 or 0