Coordination Number Definition in Chemistry

The coordination number of an atom in a molecule is the number of atoms bonded to the atom. In chemistry and crystallography, the coordination number describes the number of neighbor atoms with respect to a central atom. The term was originally defined in 1893 by Swiss chemist Alfred Werner (1866–1919). The value of the coordination number is determined differently for crystals and molecules. The coordination number can vary from as low as 2 to as high as 16. The value depends on the relative sizes of the central atom and ligands and by the charge from the electronic configuration of an ion. The coordination number of an atom in a molecule or polyatomic ion is found by counting the number of atoms bound to it (note: not by counting the number of chemical bonds). Its more difficult to determine chemical bonding in solid-state crystals, so the coordination number in crystals is found by counting the number of neighboring atoms. Most commonly, the coordination number looks at an atom in the interior of a lattice, with neighbors extending in all directions. However, in certain contexts crystal surfaces are important (e.g., heterogeneous catalysis and material science), where the coordination number for an interior atom is the bulk coordination number and the value for a surface atom is the surface coordination number. In coordination complexes, only the first (sigma) bond between the central atom and ligands counts. Pi bonds to the ligands are not included in the calculation. Coordination Number Examples Carbon has a coordination number of 4 in a methane (CH4) molecule since it has four hydrogen atoms bonded to it.In ethylene (H2CCH2), the coordination number of each carbon is 3, where each C is bonded to 2H 1C for a total of 3 atoms.The coordination number of a diamond is 4, as each carbon atom rests at the center of a regular tetrahedron formed by four carbon atoms. Calculating the Coordination Number Here are the steps for identifying the coordination number of a coordination compound. Identify the central atom in the chemical formula. Usually, this is a transition metal.Locate the atom, molecule, or ion nearest the central metal atom. To do this, find the molecule or ion directly beside the metal symbol in the chemical formula of the coordination compound. If the central atom is in the middle of the formula, there will be neighboring atoms/molecules/ions on both sides.Add the number of atoms of the nearest atom/molecule/ions. The central atom may only be bonded to one other element, but you still need to note the number of atoms of that element in the formula. If the central atom is in the middle of the formula, youll need to add up the atoms in the entire molecule.Find the total number of nearest atoms. If the metal has two bonded atoms, add together both numbers, Coordination Number Geometry There are multiple possible geometric configurations for most coordination numbers. Coordination Number 2—linearCoordination Number 3—trigonal planar (e.g., CO32-), trigonal pyramid, T-shapedCoordination Number 4—tetrahedral, square planarCoordination Number 5—square pyramid (e.g., oxovanadium salts, vanadyl VO2), trigonal bipyramid,  Coordination Number 6—hexagonal planar, trigonal prism, octahedralCoordination Number 7—capped octahedron, capped trigonal prism, pentagonal bipyramidCoordination Number 8—dodecahedron, cube, square antiprism, hexagonal bipyramidCoordination Number 9—three-face centered trigonal prismCoordination Number 10—bicapped square antiprismCoordination Number 11—all-faced capped trigonal prismCoordination Number 12—cuboctahedron (e.g., Ceric ammonium nitrate -(NH4)2Ce(NO3)6)

How Rfid Can Revolutionize Supply Chain Management

9/24/2014 SUPPLY CHAIN MANAGEMENT ASSIGNMENT RFID technology is an emerging technology that has the potential to revolutionise supply chain management Anoop Kamboj (GMAY14IT066) S P JAIN SCHOOL OF GLOBAL MANAGEMENT Table of Contents Introduction .................................................................................................................................................. 2 How RFID can revolutionize supply chain management? ............................................................................. 2 Problems related to RFID .............................................................................................................................. 4 Conclusion†¦show more content†¦It provides accurate data regarding the flow of product to both retailer and manufacturer. This further enables the improvement of each stage of supply chain. Another alternative available is bar code but due to certain limitations, RFID is a better bet and hence the popularity has increased. The greatest use of RFID can be found in the area of supply chain management where the whole process can be automated and controlled. RFID can improve the supply chain process to a great extent in spite of the technological and social difficulties faced by the end user. RFID can help the implementation of the innovative processes like the Supply chain event management, corporate planning, forecasting and replenishment. RFID accelerates the processes of Supply Chain but at the same time increase the requirements between suppliers and retailers. How RFID can revolutionize supply chain management? RFID enables the process improvements in each stage of the supply chain and revolutionize the process as a whole. Dissecting the processes involved in the supply chain, the importance and the impact of RFID on roles can be discussed below as: Production Control: In production, each item is given its own RFID tag. This tag contains an EPC (Electronic product code) which contains the relevant product information like batch id, serial no. , expiry date etc.

Business Unit 3 Constraints of Marketing Free Essays

Constraints of marketing Legal aspects There are four legal aspects that can limit and constrain your marketing, these are the sales of goods act 1979, and this law means that all products must be ‘as described’ of ‘a reasonable quality’ and be suitable for everyday purpose and also any specific purpose agreed. E. g. We will write a custom essay sample on Business Unit 3 Constraints of Marketing or any similar topic only for you Order Now a waterproof coat must be waterproof. Another legal aspect is the trade descriptions act this means that a product cannot be sold by misleading the buyer, in the way the product was made, what it is made of or where and when it was made. E. g. You cannot say something is handmade if it is not, and a hair dryer made for drying hair, must actually dry hair. The consumer credit act 2002 protects consumer’s rights when they buy goods on credit. Traders who offer credit must have an OFT (Office of Fair Trading) licence, this deals with the method of calculating APR (Annual Percentage Rate) the form and content of the agreement, and lenders guidelines. When lending money, businesses much have interest rates clearly stated and cannot change them after you have signed up. The Data Protection Act means that any information stored by marketers must only be used for the purpose stated when collected, it must be accurate and up to date, not kept longer than the period of time stated, and obtained fairly and lawfully. It must be kept up to date as if someone passes away you should not call asking for them. Also your information is protected from unauthorised use, and cannot be passed on to other companies without your permission. The information stored is available for your inspection and correction upon your request. Voluntary codes A voluntary constraint is when a company voluntary says they will never do something or they will always do something. This could include signing a code of practice stating certain behaviours ethically, even though it cannot be legally enforced. The ASA (Advertising Standards Authority) overlook advertisements in the UK and have been controlling non-broadcast ads for nearly 50 years. They say adverts must be decent, legal, honest, and truthful. The ads online are also subject to these rules. Most companies sign up to the ASA and then on follow their rules, if the rules are broken they are not breaking the law but the ASA will publicise this and show everyone what has happened and what they have done. 2397 ads were changed or withdrawn in 2009 by the ASA. E. g. The advert, for the Ford Ka’s ‘Evil twin’ featured a pigeon-bashing four wheeler that brought the wrath of animal rights activists across the country, meaning the advert never even made it to air in the UK. Pressure groups and consumerism Pressure groups are groups of people who share the same interests in a business or product; these groups can persuade or force businesses to make changes to their products or services. E. g. cancer research focus on the particular smoking issue and attempt to reduce smoking. And Friends of the Earth are a multiple cause group who seek to influence the decisions made concerning the environment. Greenpeace seek to promote environmental issues to its members and supporters. Marketing must include promotion to get people intrested. Consumerism is ‘a social movement seeking to augment the rights of buyers in relation to sellers’ How to cite Business Unit 3 Constraints of Marketing, Papers