Postcodes in Australia
Postcodes are used in Australia to more efficiently sort and route mail within the Australian postal system. Postcodes in Australia are placed at the end of the Australian address. Postcodes were introduced in Australia in 1967 by the Postmaster-General's Department and are now managed by Australia Post, are published in booklets available from post offices or online from the Australia Post website. Australian envelopes and postcards have four square boxes printed in orange at the bottom right for the postcode; these are used. Postcodes were introduced in Australia in 1967 by the Postmaster-General's Department to replace earlier postal sorting systems, such as Melbourne's letter and number codes and a similar system used in rural and regional New South Wales; the introduction of the postcodes coincided with the introduction of a large-scale mechanical mail sorting system in Australia, starting with the Sydney GPO. By 1968, 75% of mail was using postcodes, in the same year post office preferred-size envelopes were introduced, which came to be referred to as “standard envelopes”.
Postcode squares were introduced in June 1990 to enable Australia Post to use optical character recognition software in its mail sorting machines to automatically and more sort mail by postcodes. Australian postcodes consist of four digits, are written after the name of the city, suburb, or town, the state or territory: Mr John Smith 100 Flushcombe Road BLACKTOWN NSW 2148When writing an address by hand, a row of four boxes is pre-printed on the lower right hand corner of an envelope, the postcode may be written in the boxes. If addressing a letter from outside Australia, the postcode is recorded before'Australia'. Australian postcodes are sorting information, they are linked with one area. Due to post code rationalisation, they can be quite complex in country areas; the south-western Victoria 3221 postcode of the Geelong Mail Centre includes twenty places around Geelong with few people. This means that mail for these places is not sorted until it gets to Geelong; some postcodes cover large populations, while other postcodes have much smaller populations in urban areas.
Australian postcodes range from 0200 for the Australian National University to 9944 for Cannonvale, Queensland. Some towns and suburbs have two postcodes — one for street deliveries and another for post office boxes. For example, a street address in the Sydney suburb of Parramatta would be written like this: Mr John Smith 99 George Street PARRAMATTA NSW 2150But mail sent to a PO Box in Parramatta would be addressed: Mr John Smith PO Box 99 PARRAMATTA NSW 2124Many large businesses, government departments and other institutions receiving high volumes of mail had their own postcode as a Large Volume Receiver, e.g. the Royal Brisbane and Women's Hospital has the postcode 4029, the Australian National University had the postcode 0200. More postcode ranges were made available for LVRs in the 1990s. Australia Post has been progressively discontinuing the LVR programme since 2006; the first one or two numbers show the state or territory that the postcode belongs to Sometimes near the state and territory borders, Australia Post finds it easier to send mail through a nearby post office, across the border: Some of the postcodes above may cover two or more states.
For example, postcode 2620 covers both a locality in NSW as well as a locality in the ACT, postcode 0872 covers a number of localities across WA, SA, NT and QLD. Three locations straddle the NSW-Queensland border. Jervis Bay Territory, once an exclave of the ACT but now a separate territory, is geographically located on the coast of NSW, it is just south of the towns of Huskisson, with which it shares a postcode. Mail to the Jervis Bay Territory is still addressed to the ACT; the numbers used to show the state on each radio callsign in Australia are the same number as the first number for postcodes in that state, e.g. 2xx in New South Wales, 3xx in Victoria, etc. Radio callsigns pre-date postcodes in Australia by more than forty years. Australia's external territories are included in Australia Post's postcode system. While these territories do not belong to any state, they are addressed as such for mail sorting: Three scientific bases in Antarctica operated by the Australian National Antarctic Research Expeditions share a postcode with the isolated sub-Antarctic island of Macquarie Island: Each state's capital city ends with three zeroes, while territorial capital cities end with two zeroes.
Capital city postcodes were the lowest postcodes in their state or territory range, before new ranges for LVRs and PO Boxes were made available. The last number can be changed from "0" to "1" to get the postcode for General Post Office boxes in any capital city: While the first number of a postcode shows the state or territory, the second number shows a region within the state. However, postcodes with the same second number are not always next to each other; as an example, postcodes in the range 2200–2299 are split between the southern suburbs of Sydney and the Central Coast of New South Wales. Postcodes with a second number of "0" or "1" are always located within the metropolitan area of the state's capital city. Postcodes with higher secon
Hobart is the capital and most populous city of the Australian island state of Tasmania. With a population of 225,000, it is the least populated Australian state capital city, second smallest if territories are taken into account. Founded in 1804 as a British penal colony, Hobart known as Hobart Town or Hobarton, is Australia's second oldest capital city after Sydney, New South Wales. Prior to British settlement, the Hobart area had been occupied for as long as 35,000 years, by the semi-nomadic Mouheneener tribe, a sub-group of the Nuennone, or South-East tribe; the descendants of these Aboriginal Tasmanians refer to themselves as'Palawa'. Since its foundation as a colonial outpost, the city has expanded from the mouth of Sullivans Cove in a north-south direction along both banks of the Derwent River, from 22 km inland from the estuary at Storm Bay to the point where the river reverts to fresh water at Bridgewater. Penal transportation ended in the 1850s, after which the city experienced periods of growth and decline.
The early 20th century saw an economic boom on the back of mining and other primary industries, the loss of men who served in the world wars was counteracted by an influx of immigration. Despite the rise in migration from Asia and other non-English speaking parts of the world, Hobart's population remains predominantly ethnically Anglo-Celtic, has the highest percentage of Australian-born residents among the Australian capital cities. In June 2016, the estimated greater area population was 224,462; the city is located in the state's south-east on the estuary of the Derwent River, making it the most southern of Australia's capital cities. Its harbour forms the second-deepest natural port in the world, its skyline is dominated by the 1,271-metre kunanyi/Mount Wellington, much of the city's waterfront consists of reclaimed land. It is the financial and administrative heart of Tasmania, serving as the home port for both Australian and French Antarctic operations and acting as a major tourist hub, with over 1.192 million visitors in 2011/2012.
The metropolitan area is referred to as Greater Hobart, to differentiate it from the City of Hobart, one of the five local government areas that cover the city. The first European settlement began in 1803 as a military camp at Risdon Cove on the eastern shores of the Derwent River, amid British concerns over the presence of French explorers. In 1804, along with the military and convicts from the abandoned Port Phillip settlement, the camp at Risdon Cove was moved by Captain David Collins to a better location at the present site of Hobart at Sullivans Cove; the city known as Hobart Town or Hobarton, was named after Lord Hobart, the British secretary of state for war and the colonies. The area's indigenous inhabitants were members of the semi-nomadic Mouheneener tribe. Violent conflict with the European settlers, the effects of diseases brought by them reduced the aboriginal population, replaced by free settlers and the convict population. Charles Darwin visited Hobart Town in February 1836 as part of the Beagle expedition.
He writes of Hobart and the Derwent estuary in his Voyage of the Beagle:... The lower parts of the hills which skirt the bay are cleared. I was chiefly built or building. Hobart Town, from the census of 1835, contained 13,826 inhabitants, the whole of Tasmania 36,505; the Derwent River was one of Australia's finest deepwater ports and was the centre of the Southern Ocean whaling and sealing trades. The settlement grew into a major port, with allied industries such as shipbuilding. Hobart Town became a city on 21 August 1842, was renamed Hobart from the beginning of 1881. Hobart is located on the estuary of the Derwent River in the state's south-east. Geologically Hobart is built predominantly on Jurassic dolerite around the foothills interspersed with smaller areas of Triassic siltstone and Permian mudstone. Hobart extends along both sides of the Derwent River. Both of these areas rest on the younger Jurassic dolerite deposits, before stretching into the lower areas such as the beaches of Sandy Bay in the south, in the Derwent estuary.
South of the Derwent estuary lies the Tasman Peninsula. The Eastern Shore extends from the Derwent valley area in a southerly direction hugging the Meehan Range in the east before sprawling into flatter land in suburbs such as Bellerive; these flatter areas of the eastern shore rest on far younger deposits from the Quaternary. From there the city extends in an easterly direction through the Meehan Range into the hilly areas of Rokeby and Oakdowns, before reaching into the tidal flatland area of Lauderdale. Hobart has access to a number of beach areas including those in the Derwent estuary itself. Hobart has a mild temperate oceanic climate; the highest temperature recorded was 41.8 °C on 4 January 2013 and the lowest was −2.8 °C on 25 June 1972 and 11 July 1981. Annually, Hobart receives 40.8 clear days. Compared to other major Australian cities, Hobart has the fewest daily average hours of sunshine, with 5.9 hours per day. However, during the summer it has the most
Crotty is a former gazetted townsite, located in Western Tasmania, Australia. The township was located on the eastern lower slopes of Mount Jukes, below the West Coast Range, on the southern bank of the King River; the locality had had a former name of King River The town reserve was gazetted on 5 June 1900. The town survey was completed in November 1900. By 1902 there had been development of over 150 dwellings, 700 people living in the town; the last residents to move away left in 1928. In photographs found in Geoffrey Blainey's The Peaks of Lyell, the foreground shows a bridge, the Baxter River bridge; this was a crucial connection for people travelling between the railway stopping places. At the turn of the twentieth century, the township had had a smelter and railway connection with the North Mount Lyell mine; the North Mount Lyell smelters failed, despite attempts in 1902 to correct issues. The company was absorbed by the Mount Lyell Mining and Railway Company in 1903; the townsite soon lost population, the North Mount Lyell Railway which serviced Crotty's connections with Gormanston and Pillinger remained in service for a couple of decades before closing.
Most historical photos of Crotty show the smelters, the hotels, the small houses/huts. The most iconic photograph is that found in Geoffrey Blainey's The Peaks of Lyell, dated 1902, taken from the embankment just east of the railway line, looking west, up the main street with the smoke from the smelter in the air, Mount Jukes in the background. During the late 1970s and at an early stage in the "No Dams" campaign to stop the establishment of a dam on the Franklin River, a small group of musicians in Queenstown formed a group called the'Crotty Ditty Band'. During the building of the King power development in the 1980s, the Hydro Crotty Camp was home to several hundred dam construction workers In the 1990s the townsite was inundated by Lake Burbury, the result of the completed King River Power development scheme. Despite this, the Tasmanian 1:25000 Owen map still identifies the Proclaimed Town of Crotty. On the eastern shores of Lake Burbury, the land south of the Lyell Highway, adjacent to the Franklin-Gordon Wild Rivers National Park, is known as the Crotty Conservation Area.
This has an area of 44.2 square kilometres and was established on 27 December 2000. Darwin Dam Crotty Dam West Coast Tasmania Mines Atkinson, H. K.. Railway Tickets of Tasmania. ISBN 0-9598718-7-X. Rae, Lou; the Abt Railway and Railways of the Lyell region. Sandy Bay: Lou Rae. ISBN 0-9592098-7-5. Whitham, Charles. Western Tasmania – A land of riches and beauty. Queenstown: Municipality of Queenstown. List of conservation areas map with Crotty and Queenstown
Government of Australia
The Government of Australia is the government of the Commonwealth of Australia, a federal parliamentary constitutional monarchy. It is commonly referred to as the Australian Government, the Commonwealth Government, Her Majesty's Government, or the Federal Government; the Commonwealth of Australia was formed in 1901 as a result of an agreement among six self-governing British colonies, which became the six states. The terms of this contract are embodied in the Australian Constitution, drawn up at a Constitutional Convention and ratified by the people of the colonies at referendums; the Australian head of state is the Queen of Australia, represented by the Governor-General of Australia, with executive powers delegated by constitutional convention to the Australian head of government, the Prime Minister of Australia. The Government of the Commonwealth of Australia is divided into three branches: the executive branch, composed of the Federal Executive Council, presided by the Governor-General, which delegates powers to the Cabinet of Australia, led by the Prime Minister.
Separation of powers is implied by the structure of the Constitution, the three branches of government being set out in separate chapters. The Australian system of government combines elements of the Westminster and Washington systems with unique Australian characteristics, has been characterised as a "Washminster mutation". Section 1 of the Australian Constitution creates a democratic legislature, the bicameral Parliament of Australia which consists of the Queen of Australia, two houses of parliament, the Senate and the House of Representatives. Section 51 of the Constitution provides for the Commonwealth Government's legislative powers and allocates certain powers and responsibilities to the Commonwealth government. All remaining responsibilities are retained by the six States. Further, each State has its own constitution, so that Australia has seven sovereign Parliaments, none of which can encroach on the functions of any other; the High Court of Australia arbitrates on any disputes which arise between the Commonwealth and the States, or among the States, concerning their respective functions.
The Commonwealth Parliament can propose changes to the Constitution. To become effective, the proposals must be put to a referendum of all Australians of voting age, must receive a "double majority": a majority of all votes, a majority of votes in a majority of States; the Commonwealth Constitution provides that the States can agree to refer any of their powers to the Commonwealth. This may be achieved by way of an amendment to the Constitution via referendum. More powers may be transferred by passing other acts of legislation which authorise the transfer and such acts require the legislative agreement of all the state governments involved; this "transfer" legislation may have a "sunset clause", a legislative provision that nullifies the transfer of power after a specified period, at which point the original division of power is restored. In addition, Australia has several "territories", two of which are self-governing: the Australian Capital Territory and the Northern Territory; these territories' legislatures, their Assemblies, exercise powers devolved to them by the Commonwealth.
Australian citizens in these territories are represented by members of both houses of the Commonwealth Parliament. The territory of Norfolk Island was self-governing from 1979 until 2016, although it was never represented as such in the Commonwealth Parliament; the other territories that are inhabited—Jervis Bay, Christmas Island and the Cocos Islands—have never been self-governing. The federal nature of the Commonwealth and the structure of the Parliament of Australia were the subject of protracted negotiations among the colonies during the drafting of the Constitution; the House of Representatives is elected on a basis that reflects the differing populations of the States. Thus New South Wales has 48 members, but the Senate is elected on a basis of equality among the States: all States elect 12 Senators, regardless of population. This was intended to allow the Senators of the smaller States to form a majority and thus be able to amend or reject bills originating in the House of Representatives.
The ACT and the NT each elect two Senators. The third level of government after Commonwealth and State/Territory is Local government, in the form of shires and cities; the Councils of these areas are composed of elected representatives serving part-time. Their powers are devolved to them by the Territory in which they are located. Government at the Commonwealth level and the State/Territory level is undertaken by three inter-connected arms of government: Legislature: The Commonwealth Parliament Executive: The Sovereign of Australia, whose executive power is exercisable by the Governor-General, the Prime Minister and their Departments Judiciary: The High Court of Australia and subsidiary Federal courts. Separation of powers is the principle whereby the three arms of government undertake their activities separately from each other: the Legislature proposes laws in the form of Bills, provides a legislative framework for the operations of the other two a
Census in Australia
The census in Australia, or the Census of Population and Housing, collects key characteristic data on every person in Australia, the place they are staying in, on a particular night. The census is the largest statistical collection compiled by the Australian Bureau of Statistics and is held every five years. Participation in the census is compulsory; the Australian Bureau of Statistics is legislated to collect and disseminate census data under the Australian Bureau of Statistics Act 1975, the Census and Statistics Act 1905. The first Australian census was held in 1911, on the night of 2 April and subsequent censuses were held in 1921, 1933, 1947, 1954 and 1961. In 1961 the five-year period was introduced. Censuses are held on the second Tuesday of August; the most recent was held on 9 August 2016 at a cost of $440 million. The census counts all people who are located within Australia and its external and internal territories, with the exception of foreign diplomats and their families, on census night.
For the first time, in 2016 Norfolk Island was included in the Australian census rather than being conducted by the Norfolk Island Government. The census examines data such as age, incomes, dwelling types and occupancy, transportation modes, languages spoken, religion; the census is collected and published against geographic areas defined by the Australian Standard Geographical Classification. The ASGC provides a set of geographic classifications for the dissemination of all ABS statistics. In 2007 the ABS published; the primary aim of mesh blocks is to provide a building block for constructing alternative and more relevant geographies. Only data on total persons and total dwellings is released at the mesh block level. Mesh blocks will form the basis of a new statistical geography, the Australian Statistical Geography Standard; the traditional concept of a Collection District is that it was the area that one census collector can cover in about a ten-day period. In the 2001 census, collectors may be allocated more than one urban collection district because of their size.
In urban areas collection districts average about 220 dwellings. In rural areas the number of dwellings per collection district reduces as population densities decrease. For the 2016 census there were 358,122'mesh blocks' and 57,523 spatial Statistical Area Level 1 regions defined throughout Australia; the Census and Statistics Act 1905 and Privacy Act 1988 guarantee that no personally-identifiable information is released from the ABS to other government organisations, or the public. However the ABS makes confidential census data available to researchers, who must make various legal commitments before being given access. In the 1970s there was public debate about the census. In 1979 the Law Reform Commission reported on the Census. One of the key elements under question was the inclusion of names, it was found. On 18 December 2015, the ABS announced that it will retain name and address data collected in the 2016 census for up to four years; this was an increase from 18 months in the 2011 censuses.
From 1971 to 1996 the ABS had a policy of destruction of the original census forms and their electronic representations, as well as field records. Prior to that it appears there was no explicit policy of destruction, but most material had been destroyed because of lack of storage facilities; however the 2001 census offered, for the first time, an option to have personal data archived by the National Archives of Australia and released to the public 99 years and in 2001 54% of Australians agreed to do so. Indigenous Australians in contact with the colonists were enumerated at many of the colonial censuses; when the Federation of Australia occurred in 1901, the new Constitution contained a provision, which said: "In reckoning the numbers of the people of the Commonwealth, or of a State or other part of the Commonwealth, aboriginal natives shall not be counted." In 1967, a referendum was held which approved two amendments to the Australian constitution relating to indigenous Australians. The second of the two amendments deleted Section 127 from the Constitution.
It was believed at the time of the referendum, is still said, that Section 127 meant that aboriginal people were not counted in Commonwealth censuses before 1967. In fact section 127 related to calculating the population of the states and territories for the purpose of allocating seats in Parliament and per capita Commonwealth grants, its purpose was to prevent Queensland and Western Australia using their large aboriginal populations to gain extra seats or extra funds. Thus the Commonwealth Bureau of Census and Statistics interpreted Section 127 as meaning that they may enumerate "aboriginal natives" but that they must be excluded from published tabulations of population. Aboriginal people living in settled areas were counted to a greater or lesser extent in all censuses before 1967; the first Commonwealth Statistician, George Handley Knibbs, obtained a legal opinion that "persons of the half blood" or less are not "aboriginal natives" for the purposes of the Constitution. At the first Australian census in 1911 only those "aboriginal natives" living near white settlements were enumerated, the main population tables included only those of half or less aboriginal descent.
Details of "half-caste" (but not "ful
The Australian Greens known as The Greens, are a green political party in Australia. The party is a confederation of eight state and territorial parties. In addition to environmentalism, the party cites four core values: ecological sustainability, social justice, grassroots democracy and peace and non-violence. Party constituencies can be traced to various origins – notably the early environmental movement in Australia and the formation of the United Tasmania Group, one of the first green parties in the world, but the nuclear disarmament movement in Western Australia and sections of the industrial left in New South Wales. Co-ordination between environmentalist groups occurred in the 1980s with various significant protests. Key people involved in these campaigns included Bob Brown and Christine Milne who went on to contest and win seats in the Tasmanian Parliament and form the Tasmanian Greens. Following the 2016 federal election, the Australian Greens have nine senators and one member in the lower house, 23 elected representatives across state and territory parliaments, more than 100 local councillors, over 15,000 party members.
The formation of the Australian Greens in 1992 brought together over a dozen green groups, from state and local organisations, some of which had existed for 20 years. The precursor to the Tasmanian Greens, the United Tasmania Group, was founded in 1972 to oppose the construction of new dams to flood Lake Pedder; the campaign failed to prevent the flooding of Lake Pedder and the party failed to gain political representation. One of the party's candidates was Bob Brown a doctor in Launceston. In the late 1970s and 1980s, a public campaign to prevent the construction of the Franklin Dam in Tasmania saw environmentalist and activist Norm Sanders elected to the Tasmanian House of Assembly as an Australian Democrat. Brown director of the Wilderness Society, contested the election as an independent, but failed to win a seat. In 1982 Norm Sanders resigned from the THA, Brown was elected to replace him in a countback. During her 1984 visit to Australia, West German Greens parliamentarian Petra Kelly urged that the various Greens groups in Australia develop a national identity.
As a result of this, 50 Greens activists gathered in Tasmania in December to organise a national conference. The title "The Greens" had been first registered in Sydney in the 1980s by what The Monthly Magazine described as "a band of inner-city radicals committed to resident action, nuclear disarmament and urban environmental causes, such as stopping expressways and preserving parklands"; the group formed as the Sydney Greens and evolved into the Green Alliance, with the stated aim of not forming a "traditional hierarchy party". According to party co-ordinator Hall Greenland, when amalgamation with Bob Brown's Tasmanian movement was first mooted, Brown was hesitant owing to what he perceived as the "anarchic leftism" of the Sydney movement; the Greens NSW and The Greens were wary of amalgamation owing to local autonomy concerns and a 1986 attempt by Brown to form a national party failed. The movement for a national party continued however. In an effort to reduce the influence of the Democratic Socialist Party in The Greens NSW, Brown moved for a ban on dual party membership by Greens in 1991.
Following formation of the national party in 1992, regional emphasis variations remained within the Greens, with members of the "industrial left" remaining a presence in the New South Wales branch. The Green movement gained its first federal parliamentary representative when Senator Jo Vallentine of Western Australia, elected in 1984 for the Nuclear Disarmament Party and sat as an independent, was part of the formation of and joined The Greens, a party formed in Western Australia, not affiliated to the Australian Greens at that time. In 1992, representatives from around the nation gathered in North Sydney and agreed to form the Australian Greens, although the state Greens parties in Western Australia, retained their separate identities for a period. Brown resigned from the Tasmanian Parliament in 1993, in 1996 he was elected as a senator for Tasmania, the first elected as an Australian Greens candidate; the most successful Greens group during this period was The Greens, at that time still a separate organisation from the Australian Greens.
Vallentine was succeeded by Christabel Chamarette in 1992, she was joined by Dee Margetts in 1993. But Chamarette was defeated in the 1996 federal election. Margetts opposed the industrial relations reform agenda of the Howard Government. Following the'Cavalcade to Canberra' protest of 19 August 1996, in which 2000 breakaway civilians rioted in and around Parliament House, Margetts told the Senate that "The Greens do not associate ourselves with the violent action" and that while "there are some in the Greens movement who have differing opinions about that" she did not think there was "any justification for the use of violence to the extent that we saw". Margetts lost her seat in the 1998 federal election, leaving Brown as the sole Australian Greens senator; the national party resisted appointing a party leader, however Bob Brown was selected. The New South Wales Greens remained ideologically opposed to appointing a leader and continue not to appoint such a position; the WA Greens had lost office in the Senate by 1998, leaving Bob Brown as the sole representative of the party.
Thereafter, the national vote was set to increase consecutively at el
Tin is a chemical element with the symbol Sn and atomic number 50. It is a post-transition metal in group 14 of the periodic table of elements, it is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO2. Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, has two main oxidation states, +2 and the more stable +4. Tin is the 49th most abundant element and has, with 10 stable isotopes, the largest number of stable isotopes in the periodic table, thanks to its magic number of protons, it has two main allotropes: at room temperature, the stable allotrope is β-tin, a silvery-white, malleable metal, but at low temperatures it transforms into the less dense grey α-tin, which has the diamond cubic structure. Metallic tin does not oxidize in air; the first tin alloy used on a large scale was bronze, made of 1/8 tin and 7/8 copper, from as early as 3000 BC. After 600 BC, pure metallic tin was produced. Pewter, an alloy of 85–90% tin with the remainder consisting of copper and lead, was used for flatware from the Bronze Age until the 20th century.
In modern times, tin is used in many alloys, most notably tin/lead soft solders, which are 60% or more tin, in the manufacture of transparent, electrically conducting films of indium tin oxide in optoelectronic applications. Another large application for tin is corrosion-resistant tin plating of steel; because of the low toxicity of inorganic tin, tin-plated steel is used for food packaging as tin cans. However, some organotin compounds can be as toxic as cyanide. Tin is a soft, malleable and crystalline silvery-white metal; when a bar of tin is bent, a crackling sound known as the "tin cry" can be heard from the twinning of the crystals. Tin melts at low temperatures of about 232 °C, the lowest in group 14; the melting point is further lowered to 177.3 °C for 11 nm particles. Β-tin, stable at and above room temperature, is malleable. In contrast, α-tin, stable below 13.2 °C, is brittle. Α-tin has a diamond cubic crystal structure, similar to silicon or germanium. Α-tin has no metallic properties at all because its atoms form a covalent structure in which electrons cannot move freely.
It is a dull-gray powdery material with no common uses other than a few specialized semiconductor applications. These two allotropes, α-tin and β-tin, are more known as gray tin and white tin, respectively. Two more allotropes, γ and σ, exist at temperatures above 161 pressures above several GPa. In cold conditions, β-tin tends to transform spontaneously into α-tin, a phenomenon known as "tin pest". Although the α-β transformation temperature is nominally 13.2 °C, impurities lower the transition temperature well below 0 °C and, on the addition of antimony or bismuth, the transformation might not occur at all, increasing the durability of the tin. Commercial grades of tin resist transformation because of the inhibiting effect of the small amounts of bismuth, antimony and silver present as impurities. Alloying elements such as copper, bismuth and silver increase its hardness. Tin tends rather to form hard, brittle intermetallic phases, which are undesirable, it does not form wide solid solution ranges in other metals in general, few elements have appreciable solid solubility in tin.
Simple eutectic systems, occur with bismuth, lead and zinc. Tin was one of the first superconductors to be studied. Tin can be attacked by acids and alkalis. Tin can be polished and is used as a protective coat for other metals. A protective oxide layer prevents further oxidation, the same that forms on pewter and other tin alloys. Tin helps to accelerate the chemical reaction. Tin has ten stable isotopes, with atomic masses of 112, 114 through 120, 122 and 124, the greatest number of any element. Of these, the most abundant are 120Sn, 118Sn, 116Sn, while the least abundant is 115Sn; the isotopes with mass numbers have no nuclear spin, while those with odd have a spin of +1/2. Tin, with its three common isotopes 116Sn, 118Sn and 120Sn, is among the easiest elements to detect and analyze by NMR spectroscopy, its chemical shifts are referenced against SnMe4; this large number of stable isotopes is thought to be a direct result of the atomic number 50, a "magic number" in nuclear physics. Tin occurs in 29 unstable isotopes, encompassing all the remaining atomic masses from 99 to 137.
Apart from 126Sn, with a half-life of 230,000 years, all the radioisotopes have a half-life of less than a year. The radioactive 100Sn, discovered in 1994, 132Sn are one of the few nuclides with a "doubly magic" nucleus: despite being unstable, having lopsided proton–neutron ratios, they represent endpoints beyond which stability drops off rapidly. Another 30 metastable isomers have been characterized for isotopes between 111 and 131, the most stable being 121mSn with a half-life of 43.9 years. The relative differences in the abundances of tin's stable isotopes can be explained by their different modes of formation in stellar nucleosynthesis. 116Sn through 120Sn inclusive are formed in the s-process in most stars and hence they are the most common isotopes, while 122Sn and 124Sn are only formed in the r-process (rapid neutr