Phosphate
Systematic name Phosphate[1]
Identifiers
CAS number	14265-44-2 Y
PubChem	1061
ChemSpider	1032 Y
UNII	NK08V8K8HR Y
MeSH	Phosphates
ChEBI	CHEBI:18367 Y
ChEMBL	CHEMBL289287 N
Beilstein Reference	3903772
Gmelin Reference	1997
Jmol-3D images	Image 1 Image 2 Image 3
SMILES [O-]P([O-])([O-])=O [O-]P(=O)([O-])[O-] O=P([O-])([O-])[O-]
InChI InChI=1S/H3O4P/c1-5(2,3)4/h(H3,1,2,3,4)/p-3 Y Key: NBIIXXVUZAFLBC-UHFFFAOYSA-K Y
Properties
Molecular formula	PO43-
Molar mass	94.9714 g mol−1
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in agriculture and industry.^[2] At elevated temperatures in the solid state, phosphates can condense to form pyrophosphates.

Chemical properties[link]

The general chemical structure of an organophosphate.

This is the structural formula of the phosphoric acid functional group as found in a weakly acidic aqueous solution. In more basic aqueous solutions, the group donates the two hydrogen atoms and ionizes as a phosphate group with a negative charge of 2. ^[3]

The phosphate ion is a polyatomic ion with the empirical formula PO3−
4 and a molar mass of 94.97 g/mol. It consists of one central phosphorus atom surrounded by four oxygen atoms in a tetrahedral arrangement. The phosphate ion carries a negative three formal charge and is the conjugate base of the hydrogen phosphate ion, HPO2−
4, which is the conjugate base of H₂PO−
4, the dihydrogen phosphate ion, which in turn is the conjugate base of H₃PO₄, phosphoric acid. The phosphate ion is a hypervalent molecule (the phosphorus atom has 10 electrons in its valence shell). A phosphate salt forms when a positively charged ion attaches to the negatively charged oxygen atoms of the ion, forming an ionic compound. Many phosphates are not soluble in water at standard temperature and pressure. The sodium, potassium, rubidium, caesium and ammonium phosphates are all water soluble. Most other phosphates are only slightly soluble or are insoluble in water. As a rule, the hydrogen and dihydrogen phosphates are slightly more soluble than the corresponding phosphates. The pyrophosphates are mostly water soluble.

Aqueous phosphate exists in four forms. In strongly basic conditions, the phosphate ion (PO3−
4) predominates, whereas in weakly basic conditions, the hydrogen phosphate ion (HPO2−
4) is prevalent. In weakly acid conditions, the dihydrogen phosphate ion (H₂PO−
4) is most common. In strongly acidic conditions, trihydrogen phosphate (H₃PO₄) is the main form.

• 

  H₃PO₄
• 

  H₂PO−
  4
• 

  HPO2−
  4
• 

  PO3−
  4

More precisely, considering the following three equilibrium reactions:

H₃PO₄ H⁺ + H₂PO−
4

H₂PO−
4 H⁺ + HPO2−
4

HPO2−
4 H⁺ + PO3−
4

the corresponding constants at 25°C (in mol/L) are (see phosphoric acid):

Failed to parse (Missing texvc executable; please see math/README to configure.): K_{a1}=\frac{[\mbox{H}^+][\mbox{H}_2\mbox{PO}_4^-]}{[\mbox{H}_3\mbox{PO}_4]}\simeq 7.5\times10^{-3}

(pKa1 2.12)

Failed to parse (Missing texvc executable; please see math/README to configure.): K_{a2}=\frac{[\mbox{H}^+][\mbox{HPO}_4^{2-}]}{[\mbox{H}_2\mbox{PO}_4^-]}\simeq 6.2\times10^{-8}

(pKa2 7.21)

Failed to parse (Missing texvc executable; please see math/README to configure.): K_{a3}=\frac{[\mbox{H}^+][\mbox{PO}_4^{3-}]}{[\mbox{HPO}_4^{2-}]}\simeq 2.14\times10^{-13}

(pKa3 12.67)

The speciation diagram obtained using these pK values shows three distinct regions. In effect H₃PO₄, H₂PO−
4 and HPO2−
4 behave as separate weak acids. This is because the successive pK values differ by more than 4. For each acid the pH at half-neutralization is equal to the pK value of the acid. The region in which the acid is in equilibrium with its conjugate base is defined by pH ≈ pK ± 2. Thus the three pH regions are approximately 0–4, 5–9 and 10–14. This is idealized as it assumes constant ionic strength, which will not hold in reality at very low and very high pH values.

For a neutral pH as in the cytosol, pH=7.0

Failed to parse (Missing texvc executable; please see math/README to configure.): \frac{[\mbox{H}_2\mbox{PO}_4^-]}{[\mbox{H}_3\mbox{PO}_4]}\simeq 7.5\times10^4 \mbox{ , }\frac{[\mbox{HPO}_4^{2-}]}{[\mbox{H}_2\mbox{PO}_4^-]}\simeq 0.62 \mbox{ , } \frac{[\mbox{PO}_4^{3-}]}{[\mbox{HPO}_4^{2-}]}\simeq 2.14\times10^{-6}

so that only H₂PO−
4 and HPO2−
4 ions are present in significant amounts (62% H₂PO−
4, 38% HPO2−
4 Note that in the extracellular fluid (pH=7.4), this proportion is inverted (61% HPO2−
4, 39% H₂PO−
4).

Phosphate can form many polymeric ions such as diphosphate (also known as pyrophosphate), P₂O4−
7, and triphosphate, P₃O5−
10. The various metaphosphate ions (which are usually long linear polymers) have an empirical formula of PO−
3 and are found in many compounds.

Biochemistry of phosphates[link]

In biological systems, phosphorus is found as a free phosphate ion in solution and is called inorganic phosphate, to distinguish it from phosphates bound in various phosphate esters. Inorganic phosphate is generally denoted P_i and at physiological (neutral) pH primarily consists of a mixture of HPO2−
4 and H₂PO−
4 ions.

Inorganic phosphate can be created by the hydrolysis of pyrophosphate, which is denoted PP_i:

P₂O4−
7 + H₂O 2 HPO2−
4

However, phosphates are most commonly found in the form of adenosine phosphates, (AMP, ADP and ATP) and in DNA and RNA and can be released by the hydrolysis of ATP or ADP. Similar reactions exist for the other nucleoside diphosphates and triphosphates. Phosphoanhydride bonds in ADP and ATP, or other nucleoside diphosphates and triphosphates, contain high amounts of energy which give them their vital role in all living organisms. They are generally referred to as high energy phosphate, as are the phosphagens in muscle tissue. Compounds such as substituted phosphines have uses in organic chemistry but do not seem to have any natural counterparts.

The addition and removal of phosphate from proteins in all cells is a pivotal strategy in the regulation of metabolic processes.

Reference ranges for blood tests, showing inorganic phosphorus in purple at right, being almost identical to the molar concentration of phosphate.

Phosphate is useful in animal cells as a buffering agent. Phosphate salts that are commonly used for preparing buffer solutions at cell pHs include Na₂HPO₄, NaH₂PO₄, and the corresponding potassium salts.

An important occurrence of phosphates in biological systems is as the structural material of bone and teeth. These structures are made of crystalline calcium phosphate in the form of hydroxyapatite. The hard dense enamel of mammalian teeth consists of fluoroapatite, an hydroxy calcium phosphate where some of the hydroxyl groups have been replaced by fluoride ions.

Insect exoskeleta are constructed of chitin containing crystalline calcium phosphate as a strengthening material.

Occurrence and mining[link]

Phosphates are the naturally occurring form of the element phosphorus, found in many phosphate minerals. In mineralogy and geology, phosphate refers to a rock or ore containing phosphate ions. Inorganic phosphates are mined to obtain phosphorus for use in agriculture and industry.^[2]

The largest phosphorite or rock phosphate deposits in North America lie in the Bone Valley region of central Florida, United States, the Soda Springs region of Idaho, and the coast of North Carolina. Smaller deposits are located in Montana, Tennessee, Georgia and South Carolina near Charleston along Ashley Phosphate road. The small island nation of Nauru and its neighbor Banaba Island, which used to have massive phosphate deposits of the best quality, have been mined excessively. Rock phosphate can also be found in Egypt, Israel, Morocco, Navassa Island, Tunisia, Togo and Jordan, countries that have large phosphate mining industries.

Phosphorite mines are primarily found in:

• North America: United States of America, especially North Carolina, with lesser deposits in Florida, Idaho and Tennessee.
• Africa: Morocco, mainly near Khouribga and Youssoufia; Senegal, Togo, Tunisia and Western Sahara.
• Middle East: Israel, Saudi Arabia, Jordan, and Iraq, at the town of Akashat, near the Jordanian border.
• Oceania: Australia, Makatea, Nauru, and Banaba Island.

In 2007, at the current rate of consumption, the supply of phosphorus was estimated to run out in 345 years.^[4] However, some scientists now believe that a "peak phosphorus" will occur in 30 years and that at "current rates, reserves will be depleted in the next 50 to 100 years."^[5] Reserves refer to the amount assumed recoverable at current market prices, and, in 2012, the USGS estimated 71 billion tons of world reserves, while 0.19 billion tons were mined globally in 2011.^[6] Phosphorus comprises 0.1% by mass of the average rock^[7] (while, for perspective, its typical concentration in vegetation is 0.03% to 0.2%),^[8] and consequently there are quadrillions of tons of phosphorus in Earth's 3 * 10¹⁹ ton crust,^[9] albeit at predominantly lower concentration than the deposits counted as reserves from being inventoried and cheaper to extract.

Some phosphate rock deposits are notable for their inclusion of significant quantities of radioactive uranium isotopes. This syndrome is noteworthy because radioactivity can be released into surface waters^[10] in the process of application of the resultant phosphate fertilizer (e.g. in many tobacco farming operations in the southeast USA).

Ecology[link]

In ecological terms, because of its important role in biological systems, phosphate is a highly sought after resource. Once used, it is often a limiting nutrient in environments, and its availability may govern the rate of growth of organisms. This is generally true of freshwater environments, whereas nitrogen is more often the limiting nutrient in marine (seawater) environments. Addition of high levels of phosphate to environments and to micro-environments in which it is typically rare can have significant ecological consequences. For example, blooms in the populations of some organisms at the expense of others, and the collapse of populations deprived of resources such as oxygen (see eutrophication) can occur. In the context of pollution, phosphates are one component of total dissolved solids, a major indicator of water quality.

Calcium hydroxyapatite and calcite precipitates can be found around bacteria in alluvial topsoil.^[11] As clay minerals promote biomineralization, the presence of bacteria and clay minerals resulted in calcium hydroxyapatite and calcite precipitates.^[11]

Phosphate deposits can contain significant amounts of naturally occurring heavy metals. Mining operations processing phosphate rock can leave tailings piles containing elevated levels of cadmium, lead, nickel, copper, chromium, and uranium. Unless carefully managed, these waste products can leach heavy metals into groundwater or nearby estuaries. Uptake of these substances by plants and marine life can lead to concentration of toxic heavy metals in food products.^[12]

See also[link]

References[link]

External links[link]

Wikimedia Commons has media related to: Phosphates

• US Minerals Databrowser provides data graphics covering consumption, production, imports, exports and price for phosphate and 86 other minerals
• Taking Stock of Phosphorus and Biofuels, global phosphate mining, use and shortages.

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There are many people in history who are commonly appended with the phrase "the Great", or who were called that or an equivalent phrase in their own language. Other languages have their own suffixes such as e Bozorg and e azam in Persian and Urdu respectively.

In Persia, the title "the Great" at first seems to be a colloquial version of the Old Persian title "Great King". This title was first used by the conqueror Cyrus II of Persia.^[1]

The Persian title was inherited by Alexander III of Macedon (336–323 BC) when he conquered the Persian Empire, and the epithet "Great" eventually became personally associated with him. The first reference (in a comedy by Plautus)^[2] assumes that everyone knew who "Alexander the Great" was; however, there is no earlier evidence that Alexander III of Macedon was called "the Great".

The early Seleucid kings, who succeeded Alexander in Persia, used "Great King" in local documents, but the title was most notably used for Antiochus the Great (223–187 BC).

Later rulers and commanders began to use the epithet "the Great" as a personal name, like the Roman general Pompey. Others received the surname retrospectively, like the Carthaginian Hanno and the Indian emperor Ashoka the Great. Once the surname gained currency, it was also used as an honorific surname for people without political careers, like the philosopher Albert the Great.

As there are no objective criteria for "greatness", the persistence of later generations in using the designation greatly varies. For example, Louis XIV of France was often referred to as "The Great" in his lifetime but is rarely called such nowadays, while Frederick II of Prussia is still called "The Great". A later Hohenzollern - Wilhelm I - was often called "The Great" in the time of his grandson Wilhelm II, but rarely later.

Rulers[link]

• Abbas I of Persia (1571–1629), Shah of Iran
• Akbar (1542–1605), ruler of the Mughal Empire of South Asia, mainly India
• Alain I of Albret (1440–1522), French aristocrat
• Alexander the Great (356-323 BC), King of Macedonia, Persia, Greece, Egypt, and all of Mesopotamia
• Alexander I of Georgia (1386–1446), King of Georgia
• Alfonso III of León (c. 848-910), King of León, Galicia and Asturias
• Alfred the Great (848/849-899), King of Wessex
• Antiochus III the Great (c. 241–187 BC), ruler of the Seleucid Empire
• Ashoka the Great (c. 304–232 BC), Indian emperor of the Maurya dynasty
• Ashot I of Iberia “the Great”(died 826/830), presiding prince of Iberia (modern Georgia),
• Askia Mohammad I (c. 1442–1538), ruler of the Songhai Empire
• Bhumibol Adulyadej (born 1927), King of Thailand
• Bolesław I Chrobry (967-1025), sometimes called "the Great", first King of Poland
• Bruno the Great (925–965), Archbishop of Cologne and Duke of Lotharingia (also listed in the following section)
• Buddha Yodfa Chulaloke (1736–1809), founder and ruler of the Rattanakosin Kingdom (in what is now Thailand)
• Cnut the Great (c. 985 or 995-1035), King of Denmark, England, Norway and parts of Sweden
• Casimir III the Great (1310–1370), King of Poland
• Catherine the Great (1729–1796), Empress of Russia
• Chandragupta II (reigned 375-413/415), also known as Vikramaditya, ruler of the Gupta empire in India
• Charlemagne (died 814), King of the Franks and Emperor of the Romans
• Chulalongkorn (1853–1910), King of Siam (now Thailand)
• Chlothar II (584-629), King of Neustria and King of the Franks
• Conrad, Margrave of Meissen (c. 1097-1157), Margrave of Meissen
• Constantine I (c. 272-337), Roman emperor
• Cyaxares the Great (c. 625-585 BC), third king of Media
• Cyrus the Great (c. 600 BC or 576 BC–530 BC), founder and ruler of the Persian or Achaemenid Empire
• Darius the Great (550 – 486 BC), third ruler of the Persian Empire
• Devapala (died 850), ruler of the Pala Empire in the Indian subcontinent
• Dionysius I, Greek tyrant of Syracuse^[3]
• Ferdinand I of León and Castile (c. 1015–1065), King of León and Count of Castile
• Frederick the Great (1712–1786), King of Prussia
• Genghis Khan (1162?-1227), founder and Great Khan of the Mongol Empire
• Gero (c. 900–965), ruler of Marca Geronis, a very large march in Europe
• Gustavus Adolphus of Sweden (1594–1632), King of Sweden, founder of the Swedish Empire, and noted military leader
• Gwanggaeto the Great, King of Goguryeo, one of the Three Kingdoms of Korea^[4][5]
• Hanno the Great, the name of three leaders of Carthage, in the 4th, 3rd, and 2nd centuries BC
• Henry I, Duke of Burgundy (946–1002)
• Henry IV of France (1553–1610), King of France and King of Navarre
• Herod the Great (73/74 BC-4 BC), King of Judea
• Hugh the Great (898-956), Duke of the Franks and Count of Paris
• Hugh Magnus of France (1007–1025), co-King of France
• Hugh I, Count of Vermandois (1057–1101)
• Humphrey I de Bohun (died c. 1123), Anglo-Norman aristocrat
• Ivan III of Russia (1440–1505), Tsar of Russia
• John I of Portugal (1358–1433), King of Portugal and the Algarve
• John II of Aragon (1398–1479), King of Aragon and, through his wife, King of Navarre
• Justinian I (483-565), Byzantine Emperor
• Kamehameha I (c. 1758-1819), first King of Hawai'i
• Kanishka (died c. 127), ruler of the Kushan Empire in Central Asia and parts of India
• Kvirike III of Kakheti (1010–1029), King of Kakheti in eastern Georgia
• Kublai Khan (1215–1294), Mongol ruler in the 13th century and Emperor of China; founder of the Yuan Dynasty
• Llywelyn the Great (c. 1172–1240), Prince of Gwynedd and de facto ruler of most of Wales
• Louis I of Hungary (1326–1382), King of Hungary, Croatia and Poland
• Mangrai the Great (1238–1317), Lanna, northern Thailand
• Emperor Meiji (1852–1912), Emperor of Japan
• Mircea I of Wallachia (1355–1418)
• Mithridates II of Parthia (died 88 BC), ruler of the Parthian Empire (in present day Iran)
• Mithridates VI of Pontus (134 BC–63 BC), ruler of Pontus and the Bosporan Kingdom
• Mstislav I of Kiev (1076–1132), Grand Prince of Kievan Rus
• Naresuan (1555–1605), King of Ayutthaya
• Narai (1633–1688), King of Ayutthaya (in what is now modern Thailand)
• Odo the Great (died c. 735), Duke of Aquitaine
• Otto I, Holy Roman Emperor (912-973)
• K'inich Janaab' Pakal (603-683), ruler of the Mayan city-state of Palenque
• Parakramabahu I of Polonnaruwa (1123–1186), King of Sri Lanka
• Peter Krešimir IV of Croatia (died 1075), King of Croatia
• Peter the Great (1672–1725), Tsar of Russia
• Peter III of Aragon (1239–1285), King of Aragon and King of Sicily
• Pompey (106 BC-48 BC), military and political leader of the late Roman Republic, rival of Julius Caesar
• Radama I (1793–1828), first king of greater Madagascar
• Raja Raja Chola I (c. 947-1014), Indian emperor of the Cholas.^[6][7][8]
• Rajendra Chola I (reigned 1014–1044), Tamil King of India
• Ramesses II (reigned 1279 BC – 1213 BC), considered the greatest pharaoh of Ancient Egypt
• Ram Khamhaeng (around 1237 to 1247-1298), King of Sukhothai (in present day Thailand)
• Ramon Berenguer III, Count of Barcelona (1082–1131), also Count of Provence and various other counties
• Rhodri the Great (c. 820–878), King of Gwynedd (in present day Wales)
• Roman the Great (after 1160-1205), Grand Prince of Kiev
• Saladin (c. 1138-1193), Kurdish Sultan of Egypt and Syria, founder of the Ayyubid dynasty, and victor over the Crusaders
• Samudragupta (c. 335–375), ruler of the Gupta empire in the Indian subcontinent
• Sancho III of Navarre (c. 992-1035), King of Kingdom of Navarre
• Sargon of Akkad (died c. 2215 BC), ruler of the Akkadian Empire
• Sejong the Great (1397–1450), Korean king^[9]
• Shapur II (309-379), king of the Sassanid Empire, Persia
• Simeon I of Bulgaria (864/865-927), ruler of the First Bulgarian Empire
• Stephen III of Moldavia (1433–1504), Prince of Moldavia (Romania)
• Stephen Uroš IV Dušan of Serbia (c. 1308-1355), King of Serbia and Emperor of the Serbs and Greeks
• Taksin (1734–1782), King of the Thonburi Kingdom (Thailand)
• Tamar (1160-1123), Queen of the Georgian Empire
• Timur (1336–1405), better known as Tamerlane, founder of the Timurid Dynasty
• Theobald II, Count of Champagne (1090–1151), Count of Blois and of Chartres as Theobald IV, Count of Champagne and of Brie
• Theodoric the Great (454-526), King of the Ostrogoths, regent of the Visigoths and a viceroy of the Byzantine Empire
• Theodosius I (347-395), Roman emperor
• Tigranes the Great (140-55 BC), Emperor of Armenia
• Tiridates III of Armenia (285-339), King of Armenia
• Umar (c. 586 to 590–644), second caliph of the Muslim Empire
• Valdemar I of Denmark (1131–1182), King of Denmark
• Valentinian I (364-375), Roman Emperor
• Vladimir I of Kiev (c. 958-1015), ruler of Kievan Rus
• Vytautas (c. 1350-1430), archduke of the Lithuanian Grand Duchy
• William I, Count of Burgundy (1020–1087), Count of Burgandy and Mâcon
• William V, Duke of Aquitaine (969-1030), also Count of Poitou
• Xerxes I (519-465 BC), King of Kings of the Achaemenid Empire (Persia)
• Yu the Great (c. 2200-2100 BC), legendary ruler in ancient China

Religious figures[link]

• Abraham the Great of Kashkar (ca. 492-586), monk and saint of the Assyrian Church of the East
• Abraham Kidunaia (died c. 366, hermit, priest, and Christian saint of Mesopotamia
• Albertus Magnus (1193/1206–1280), medieval German philosopher and theologian
• Anthony the Great (c. 251–356), early Christian saint of Egypt
• Babai the Great (c. 551–628), Assyrian church leader
• Basil of Caesarea (330-379), Greek bishop and theologian
• Bruno the Great (925–965), Archbishop of Cologne and Duke of Lotharingia (also listed in the previous section)
• Euthymius the Great (377-473), abbot and Roman Catholic and Eastern Orthodox saint
• Gertrude the Great (1256-c. 1302), German Benedictine, mystic, theologian and Roman Catholic saint
• Pope Gregory I (c. 540-604)
• Hiyya the Great, 3rd-century rabbi, Palestine
• Pope John Paul II (1920–2005)
• Pope Leo I (c. 391 or 400-461)
• Macarius of Egypt (c. 300-391), Egyptian hermit
• Pope Nicholas I (c. 800-867)
• Photius I of Constantinople (c. 810–c. 893), Eastern Orthodox saint and Patriarch of Constantinople
• William of Maleval (died 1157), founder of the Catholic congregation of Williamites

Other[link]

• Beli Mawr, a figure in medieval Welsh literature and genealogies
• Emmy the Great, folk singer
• Matteo Rosso the Great, Roman politician and father of Pope Nicholas III
• Prokop the Great, Hussite general in Bohemia

See also[link]

• Epithet
• List of monarchs by nickname
• List of nicknames of European Royalty and Nobility: G-I
• James, son of Zebedee, also known as James the Greater, one of the twelve apostles of Jesus
• Ajax (mythology), called Ajax the Greater
• Mohandas Karamchand Gandhi, whose common honorific "Mahatma" means "Great Soul"

Notes[link]