World War II
World War II known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries; the major participants threw their entire economic and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China, it included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, the only use of nuclear weapons in war. Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is said to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. Following the onset of campaigns in North Africa and East Africa, the fall of France in mid 1940, the war continued between the European Axis powers and the British Empire. War in the Balkans, the aerial Battle of Britain, the Blitz, the long Battle of the Atlantic followed. On 22 June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history; this Eastern Front trapped most crucially the German Wehrmacht, into a war of attrition. In December 1941, Japan launched a surprise attack on the United States as well as European colonies in the Pacific. Following an immediate U. S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers declared war on the U.
S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories; the Axis advance in the Pacific halted in 1942. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands; the war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945.
Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese. World War II changed the political social structure of the globe; the United Nations was established to foster international co-operation and prevent future conflicts. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia.
Most countries whose industries had been damaged moved towards economic expansion. Political integration in Europe, emerged as an effort to end pre-war enmities and create a common identity; the start of the war in Europe is held to be 1 September 1939, beginning with the German invasion of Poland. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred and the two wars merged in 1941; this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935; the British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the fo
Ordnance QF 6-pounder
The Ordnance Quick-Firing 6-pounder 7 cwt, or just 6 pounder, was a British 57 mm gun, serving as a primary anti-tank gun of the British Army during World War II, as well as the main armament for a number of armoured fighting vehicles. Although planned before the start of the war, it did not reach service until the North African Campaign in April 1942. There, it replaced the 2 pounder in the anti-tank role, allowing the 25 pounder gun-howitzer to revert to its intended artillery role; the United States Army adopted the 6 pounder as their primary anti-tank gun under the designation 57 mm Gun M1. Limitations of the existing 2-pounders were apparent as the gun was first entering service, an effort was made to replace it with a much more capable weapon starting as early as 1938; the Woolwich Arsenal was entrusted with the development of a new gun with a calibre of 57 mm. Guns of this calibre had been employed by the Royal Navy from the late 19th century, therefore manufacturing equipment was available.
The gun design was complete by 1940, but the carriage design was not completed until 1941. The production was further delayed by the defeat in the Battle of France; the loss of equipment - most of the BEF's heavy equipment had to be left behind in France during Operation Dynamo - and the prospect of a German invasion made re-equipping the army with anti-tank weapons an urgent task, so a decision was made to carry on the production of the 2 pounder, avoiding the period of adaptation to production, of re-training and acclimatisation with the new weapon. It was estimated; this had the effect of delaying production of the 6-pounder until November 1941 and its entry into service until May 1942. Unlike the 2-pounder, the new gun was mounted on a conventional two-wheeled split trail carriage; the first mass production variant—the Mk II—differed from the pre-production Mk I in having a shorter L/43 barrel, because of the shortage of suitable lathes. The subsequent Mk IV was fitted with muzzle brake. Optional side shields were issued to give the crew better protection, but were rarely used.
The 6-pounder was used where possible to replace the 2-pounder in current British tanks, requiring work on the turrets, pending the introduction of new tanks designed to take the 6-pounder from the outset. The Churchill Marks III and IV, Valentine Mark IX and Crusader Mark III all began to enter service during 1942; the Valentine and Crusader both needed to lose a crew member from the turret. Those tanks designed to take the 6-pounder from the outset were the problematic Cavalier, the Cromwell and the Centaur. However, when the Cromwell went into combat in 1944, it was armed with the Ordnance QF 75 mm gun, a redesign of the 6-pounder to take US 75 mm ammunition and more useful against general targets; the 6-pounder was fitted to the AEC Armoured Car Mark II. Although the 6-pounder was kept at least somewhat competitive through the war, the Army started development of a more powerful weapon in 1942; the aim was to produce a gun with the same general dimensions and weight as the 6-pounder, but with improved performance.
The first attempt was an 8-pounder of 59 calibre length, but this version proved too heavy to be used in the same role as the 6-pounder. A second attempt was made with a shorter 48 calibre barrel, but this proved to have only marginally better performance than the 6-pounder; the program was cancelled in January 1943. Instead, the 6-pounder was followed into production and service by the next generation British anti-tank gun, the 17 pounder, which came into use from February 1943; as a smaller and more manoeuvrable gun, the 6-pounder continued to be used by the British Army not only for the rest of World War II, but for some 20 years afterwards. A 57/42.6 mm squeeze was never adopted. In addition to the UK, the gun was produced in both South Africa, where the Combined Ordnance Factories produced 300, Canada; the idea of manufacturing the 6 pounder in the US was expressed by the US Army Ordnance in February 1941. At that time, the US Army still favoured the 37mm Gun M3 and production was planned for lend lease.
The US version, classified as substitute standard under the designation 57 mm Gun M1, was based on the 6 pounder Mark II, two units of which were received from the UK. However, since there was sufficient lathe capacity, the longer barrel could be produced from the start. Production started early in 1942 and continued until 1945; the M1A1 variant used wheels. The M1A2 introduced the British practice of free traverse, meaning that the gun could be traversed by the crew pushing and pulling on the breech, instead of geared traverse, from September 1942; the M1 was made standard issue in the Spring of 1943. A more stable carriage was developed but not introduced. Once the 57mm entered US service, a modified towing point design was introduced, but only for US use. Tractors for the M1 included the Dodge WC-63 1 1⁄2 - the White Half-Track. Two-thirds of American production went to US Army Divisions in Europe. About one-third of production was delivered to the UK and 400 guns were sent to Russia through Lend Lease.
When the United States re-armed and re-equipped Free French forces for the Normandy landings, their Anti-Tank units received American-made M1s. Like the British Army, the US Army experimented with a squeeze bore adaptor, but the program was abandoned. American shell designs and production lagged behind the introduction of the gun once it was accepted for service and so, at first, only AP shot was available; the HE shell was not available until after the Normandy land
4.2 cm Pak 41
The 4.2 cm Pak 41 was a light anti-tank gun issued to German airborne units in World War II. This gun was externally similar to the 3.7 cm Pak 36, using a modified version of the latter's carriage, but used the squeeze bore principle to boost its velocity, hence armour-piercing ability. The bore tapered down to 28 mm at the muzzle. Production was terminated in May 1942 after the delivery of 136 guns. By November 1944, 41 remained in service. Projectile weight: AP 0.336 kg 2.8 cm sPzB 41 7.5 cm Pak 41 Littlejohn adaptor Gander and Chamberlain, Peter. Weapons of the Third Reich: An Encyclopedic Survey of All Small Arms and Special Weapons of the German Land Forces 1939-1945. New York: Doubleday, 1979 ISBN 0-385-15090-3 Hogg, Ian V. German Artillery of World War Two. 2nd corrected edition. Mechanicsville, PA: Stackpole Books, 1997 ISBN 1-85367-480-X
The Tank Museum
The Tank Museum is a collection of armoured fighting vehicles at Bovington Camp in Dorset, South West England. It is about 1 mile north of the village of Wool and 12 miles west of the major port of Poole; the collection traces the history of the tank. With 300 vehicles on exhibition from 26 countries it is the largest collection of tanks and the third largest collection of armoured vehicles in the world, it includes Tiger 131, the only working example of a German Tiger I tank, a British First World War Mark I, the world's oldest surviving combat tank. It is the museum of the Royal Tank Regiment and the Royal Armoured Corps and is a registered charity; the writer Rudyard Kipling visited Bovington in 1923 and, after viewing the damaged tanks, salvaged at the end of the First World War, recommended a museum should be set up. Accordingly a shed was established to house the collection but was not opened to the general public until 1947. George Forty, appointed Director of the Museum in 1982, expanded and modernized the collection.
He retired in 1993 after which he received an OBE. The museum established its own YouTube channel to teach about the tanks in January 2010. David Fletcher, an historian at the museum since 1982, retired in 2012 and was appointed an MBE "for his services to the history of armoured warfare". World War I Hall As well as containing the majority of the museum's World War I tanks this hall tells the story of men who crewed the first tanks between 1916 and 1918. Featured tanks: Mark I tank, IV, V, IX & Mark VIII "Liberty" tanks. Inter War Hall This hall now explores the rise of the tank and the role of the cavalry on the Western Front. Featured tanks: Vickers A1E1 Independent, Peerless Armoured Car & Vickers Light tank, Mark II. World War II Hall This hall displays the biggest section, with tanks from most nations involved in the conflict. Featured tanks: Panzer I, III, IV, Stug III, Tiger II, Jagdpanzer 38, Jagdtiger, Sd. Kfz. 251, Somua S35, Comet I, Matilda Mk I, A38 Valiant, Ram Cruiser Mk II, M24 Chaffee, M4 Sherman, M10 Tank Destroyer, M48 Patton, M26 Pershing, T17E1 Staghound, Hamilcar glider, DUKW, SU-76, T-26, KV-1, L3/33 LF, M13/40, Black Prince.
Battlegroup Afghanistan This hall contains the Battlegroup Afghanistan exhibition. The men of the Royal Armoured Corps who have been involved in some of the fiercest fighting since World War Two. Featured tanks: Conqueror, Challenger 1 and TOG2. Tank FactoryThis hall explores technology that goes into making tanks and AFVs. There is a mock production line of Centurions, as well as experimental vehicles. Featured tanks: a T-55 with sections cut out enabling visitors to see inside, Swedish S tank, prototype FV101 Scorpion and various Ferret armoured cars, along with the first M4 Sherman supplied to the British in World War II, an A13 Covenanter; the Tank Story HallThis hall holds some of the most important tanks and AFVs in history, with a supporting collection housed in a multimedia exhibition. It follows the story of the tank, from its invention in 1915 through the 20th century and into the future. Featured tanks: Little Willie, Whippet, FT17, Char B1, Panzer II, Tiger 131, M3 Grant, T-34, Panther, DD Sherman Churchill Mk VII, Sherman Firefly, M48 Patton, T-72, T-62 and Challenger 2The Vehicle Conservation CentreThe Vehicle Conservation Centre provides cover for more of the collection and puts on view vehicles that had not been seen by the public.
Featured tanks: Charioteer, M41 Bulldog, M103, M60 Patton, T-54, Cold War and Iraqi T-55s, BMP-1, AMX-30, Type 69, Infanterikanonvagn 91, A33 Excelsior, T14 and SU-100. Tank museumsKubinka Tank Museum – Russia Musée des Blindés – France Military museum Lešany – Czech Republic Deutsches Panzermuseum – Germany Patton Museum of Cavalry and Armor – United States Yad La-Shiryon – Latrun, Israel Parola Tank Museum – Finland Australian Armour and Artillery Museum – Australia Nationaal Militair Museum – Soesterberg, The Netherlands Royal Tank Museum – Amman, Jordan American Heritage Museum – United StatesOtherUnited States Army Ordnance Museum Polish Army Museum – large collection of Soviet and Polish AFVs Heartland Museum of Military Vehicles Nebraska, US. Ontario Regiment Museum Ontario, Canada Base Borden Military Museum Ontario, Canada Lists of armoured fighting vehicles Tank classification Tank Museum website Tank100 blog commemorating the centenary of the First World War. Tiger Collection blog Rio de Janeiro's military vehicle modeling association – photographs inside the museum
Armored car (military)
A military armored car is a lightweight wheeled armored fighting vehicle employed for reconnaissance, internal security, armed escort, other subordinate battlefield tasks. With the gradual decline of mounted cavalry, armored cars were developed for carrying out duties assigned to horsemen. Following the invention of the tank, the armored car remained popular due to its comparatively simplified maintenance and low production cost, it found favor with several colonial armies as a cheaper weapon for use in underdeveloped regions. During World War II, most armored cars were engineered for reconnaissance and passive observation, while others were devoted to communications tasks; some equipped with heavier armament could substitute for tracked combat vehicles in favorable conditions—such as pursuit or flanking maneuvers during the North African Campaign. Since World War II the traditional functions of the armored car have been combined with that of the armored personnel carrier, resulting in such multipurpose designs as the BTR-40 or the Cadillac Gage Commando.
Postwar advances in recoil control technology have made it possible for a few armored cars, including the B1 Centauro, the AMX-10RC and EE-9 Cascavel, to carry a large cannon capable of threatening many tanks. During the Middle Ages, war wagons covered with steel plate, crewed by men armed with primitive hand cannon and muskets, were used by the Hussite rebels in Bohemia; these were deployed in formations where the horses and oxen were at the centre, the surrounding wagons were chained together as protection from enemy cavalry. Similar wagons were used by the English army of Henry VIII, by the Chinese Empire. With the invention of the steam engine, Victorian inventors designed prototype self-propelled armored vehicles for use in sieges, although none were deployed in combat. H. G. Wells' short story The Land Ironclads provides a fictionalised account of their use; the Motor Scout was designed and built by British inventor F. R. Simms in 1898, it was the first armed petrol engine-powered vehicle built.
The vehicle was a De Dion-Bouton quadricycle with a mounted Maxim machine gun on the front bar. An iron shield in front of the car protected the driver. Another early armed car was invented by Royal Page Davidson at Northwestern Military and Naval Academy in 1898 with the Davidson-Duryea gun carriage and the Davidson Automobile Battery armored car. However, these were not'armored cars' as the term is understood today, as they provided little or no protection for their crews from enemy fire, they were by virtue of their small capacity engines, less efficient than the cavalry and horse-drawn guns that they were intended to complement. At the beginning of the 20th century, the first military armored vehicles were manufactured, by adding armor and weapons to existing vehicles; the first armored car was the Simms' Motor War Car, designed by F. R. Simms and built by Vickers, Sons & Maxim of Barrow on a special Coventry-built Daimler chassis with a German-built Daimler motor in 1899. and a single prototype was ordered in April 1899 The prototype was finished in 1902, too late to be used during the Boer War.
The vehicle had Vickers armour 6 mm thick and was powered by a four-cylinder 3.3-litre 16-hp Cannstatt Daimler engine, giving it a maximum speed around 9 miles per hour. The armament, consisting of two Maxim guns, was carried in two turrets with 360° traverse, it had a crew of four. Simms' Motor War Car was presented at the Crystal Palace, London, in April 1902. Another early armored car of the period was the French Charron, Girardot et Voigt 1902, presented at the Salon de l'Automobile et du cycle in Brussels, on 8 March 1902; the vehicle was equipped with a Hotchkiss machine gun, with 7 mm armour for the gunner. One of the first operational armoured cars with four wheel drive and enclosed rotating turret, was the Austro-Daimler Panzerwagen built by Austro-Daimler in 1904, it was armoured with 3-3.5 mm thick curved plates over the body and had a 4mm thick dome-shaped rotating turret that housed one or two machine-guns. It had a 4-cylinder 35 hp 4.4 litre engine giving it average cross country performance.
Of note, both the driver and co-driver had adjustable seats enabling them to raise them to see out of the roof of the drive compartment as needed. The Italians used armored cars during the Italo-Turkish War. A great variety of armored cars appeared on both sides during World War I and these were used in various ways. Armored cars were used by more or less independent car commanders. However, sometimes they were used in larger units up to squadron size; the cars were armed with light machine guns, but larger units employed a few cars with heavier guns. As air power became a factor, armored cars offered a mobile platform for antiaircraft guns; the first effective use of an armored vehicle in combat was achieved by the Belgian Army in August–September 1914. They had placed a Hotchkiss machine gun on Minerva touring cars, their successes in the early days of the war convinced the Belgian GHQ to create a Corps of Armoured Cars, who would be sent to fight on the Eastern front once the western front immobilized after the Battle of the Yser.
The British Royal Naval Air Service dispatched aircraft to Dunkirk to defend the UK from Zeppelins. The officers' cars followed them and these began to be used to rescue downed reconnaissance pilots in the battle areas, they mounted machine guns on them and as these excursions became dangerous, they improvised boiler plate armoring on the vehicles provided by a local shipbuilder. In London Murray Sueter ordered "fighting cars" based on Rolls-Royce and Wolseley chassis
Daimler Armoured Car
The Daimler Armoured Car was a successful British armoured car design of the Second World War that continued in service into the 1950s. It was designed for armed liaison purposes. During the postwar era, it doubled as an internal security vehicle in a number of countries. Former British Daimler armoured cars were exported to various Commonwealth of Nations member states throughout the 1950s and 1960s. In 2012, some were still being operated by the Qatari Army; the Daimler Armoured Car was a parallel development to the Daimler Dingo "Scout car", a small armoured vehicle for scouting and liaison roles. It was another Birmingham Small Arms design. A larger version designed on the same layout as the Dingo fitted with the turret similar to that of the Mark VII Light Tank and a more powerful engine. Like the scout car, it incorporated some of the most advanced design concepts of the time and is considered one of the best British AFVs of the Second World War; the 95 hp engine was at the rear linked through a fluid flywheel to a Wilson preselector gearbox and a H-drive arrangement with propshafts to each wheel.
Four wheel steering similar to early models of the Scout car was considered but not implemented following experience with the Dingo. The prototypes had been produced in 1939, but problems with the transmission caused by the weight of the vehicle delayed service entry until mid-1941. Daimler built 2,694 armoured cars; the Daimler had four wheel drive. Epicyclic gearing in the wheel hubs enabled a low ratio in bottom gear - it was credited with managing 1:2 inclines; the rugged nature combined with reliability made it ideal for escort work. The variant of the turret and the 2pdr gun were used on the Light Tank Mk VII Tetrarch; the Daimler saw action in North Africa with the Derbyshire Yeomanry. It was used in Europe and a few vehicles reached the South-East Asia theatre. A typical late war recce troop in north-west Europe would have two Daimler Armoured Cars and two Daimler Dingo scout cars. A British Indian Army armoured car regiment, the 16th Light Cavalry, which formed part of Fourteenth Army troops was equipped with Daimlers and served in the reconquest of Burma.
To improve the gun performance, some Daimlers in the European Theatre had their 2-pounders fitted with the Littlejohn adaptor, which worked on the squeeze bore principle. This increased the gun's theoretical armour penetration and would allow it to penetrate the side or rear armour of some German tanks. Daimlers were used by the territorial units of the British Army until the 1960s, outlasting their planned replacement, the Coventry Armoured Car, it was still being used, along with Daimler Dingoes, by B Squadron, 11th Hussars in Northern Ireland as late as January 1960. An Indian Army regiment, 63 Cavalry, was raised with Humber Armoured Cars in one of its squadrons; this squadron was hived off as an independent reconnaissance squadron and the integral squadron re-raised with Daimlers. In the early sixties and Daimlers of the Indian Army formed the mounts of the President's Bodyguard and were deployed in the defense of Chushul during the 1962 Sino-Indian War. Second World War Korean War Vietnam War 1948 Arab–Israeli War Indo-Pakistani War Ceylonese insurrection of 1971 Sri Lankan civil war Mark I.
Mark I CS - close support version with 76 mm gun. Mark II - improved turret, modified gun mount, better radiator, driver escape hatch incorporated into roof, WP Grenade container fitted in turret and smoke generator container modified. A turretless regimental command version, known as SOD. Qatar Australia Belgium Canada India Israel Malaysia New Zealand Poland Sri Lanka United Kingdom "Armoured Car, Mark II". Tank Museum, Bovington. Retrieved 26 February 2013. Collection record Missing-lynx.com World War II vehicles Daimler Armoured Car at Tanxheaven.com:. The Daimler Fighting Vehicles Project
Tungsten, or wolfram, is a chemical element with symbol W and atomic number 74. The name tungsten comes from the former Swedish name for the tungstate mineral scheelite, tung sten or "heavy stone". Tungsten is a rare metal found on Earth exclusively combined with other elements in chemical compounds rather than alone, it was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite; the free element is remarkable for its robustness the fact that it has the highest melting point of all the elements discovered, melting at 3422 °C. It has the highest boiling point, at 5930 °C, its density is 19.3 times that of water, comparable to that of uranium and gold, much higher than that of lead. Polycrystalline tungsten is an intrinsically hard material, making it difficult to work. However, pure single-crystalline tungsten can be cut with a hard-steel hacksaw. Tungsten's many alloys have numerous applications, including incandescent light bulb filaments, X-ray tubes, electrodes in gas tungsten arc welding and radiation shielding.
Tungsten's hardness and high density give it military applications in penetrating projectiles. Tungsten compounds are often used as industrial catalysts. Tungsten is the only metal from the third transition series, known to occur in biomolecules that are found in a few species of bacteria and archaea, it is the heaviest element known to be essential to any living organism. However, tungsten interferes with molybdenum and copper metabolism and is somewhat toxic to more familiar forms of animal life. In its raw form, tungsten is a hard steel-grey metal, brittle and hard to work. If made pure, tungsten retains its hardness, becomes malleable enough that it can be worked easily, it is worked by drawing, or extruding. Tungsten objects are commonly formed by sintering. Of all metals in pure form, tungsten has the highest melting point, lowest vapor pressure, the highest tensile strength. Although carbon remains solid at higher temperatures than tungsten, carbon sublimes at atmospheric pressure instead of melting, so it has no melting point.
Tungsten has the lowest coefficient of thermal expansion of any pure metal. The low thermal expansion and high melting point and tensile strength of tungsten originate from strong covalent bonds formed between tungsten atoms by the 5d electrons. Alloying small quantities of tungsten with steel increases its toughness. Tungsten exists in two major crystalline forms: α and β; the former is the more stable form. The structure of the β phase is called A15 cubic. Contrary to the α phase which crystallizes in isometric grains, the β form exhibits a columnar habit; the α phase has one third of the electrical resistivity and a much lower superconducting transition temperature TC relative to the β phase: ca. 0.015 K vs. 1–4 K. The TC value can be raised by alloying tungsten with another metal; such tungsten alloys are sometimes used in low-temperature superconducting circuits. Occurring tungsten consists of four stable isotopes and one long-lived radioisotope, 180W. Theoretically, all five can decay into isotopes of element 72 by alpha emission, but only 180W has been observed to do so, with a half-life of ×1018 years.
The other occurring isotopes have not been observed to decay, constraining their half-lives to be at least 4 × 1021 years. Another 30 artificial radioisotopes of tungsten have been characterized, the most stable of which are 181W with a half-life of 121.2 days, 185W with a half-life of 75.1 days, 188W with a half-life of 69.4 days, 178W with a half-life of 21.6 days, 187W with a half-life of 23.72 h. All of the remaining radioactive isotopes have half-lives of less than 3 hours, most of these have half-lives below 8 minutes. Tungsten has 11 meta states, with the most stable being 179mW. Elemental tungsten resists attack by oxygen and alkalis; the most common formal oxidation state of tungsten is +6, but it exhibits all oxidation states from −2 to +6. Tungsten combines with oxygen to form the yellow tungstic oxide, WO3, which dissolves in aqueous alkaline solutions to form tungstate ions, WO2−4. Tungsten carbides are produced by heating powdered tungsten with carbon. W2C is resistant to chemical attack, although it reacts with chlorine to form tungsten hexachloride.
In aqueous solution, tungstate gives the heteropoly acids and polyoxometalate anions under neutral and acidic conditions. As tungstate is progressively treated with acid, it first yields the soluble, metastable "paratungstate A" anion, W7O6–24, which over time converts to the less soluble "paratungstate B" anion, H2W12O10–42. Further acidification produces the soluble metatungstate anion, H2W12O6–40, after which equilibrium is reached; the metatungstate ion exists as a symmetric cluster of twelve tungsten-oxygen octahedra known as the Keggin anion. Many other polyoxometalate anions exist as metastable species; the inclusion of a different atom such as phosphorus in place of the two central hydrogens in metatungstate produces a wide v