Editing Carbon group

{{short description|Periodic table group}}
{{Infobox periodic table group
| title       = Carbon&nbsp;group&nbsp;(group 14)
| group number= 14
| trivial name= tetrels
| by element  = carbon group
| CAS         = IVA
| old IUPAC   = IVB
| mark        = C,Si,Ge,Sn,Pb,Fl
| left        = [[boron group]]
| right       = [[pnictogen]]s}}
{| class="floatright"
! colspan=2 style="text-align:left;" | ↓&nbsp;<small>[[Period (periodic table)|Period]]</small>
|-
! [[Period 2 element|2]]
| {{element cell image|6|Carbon|C| |Solid|Other nonmetal|Primordial|image=Diamond-and-graphite-with-scale.jpg|image caption=Diamond and graphite, two allotropes of carbon}}
|-
! [[Period 3 element|3]]
| {{element cell image|14|Silicon|Si| |Solid|Metalloid|Primordial|image=SiliconCroda.jpg|image caption=Purified silicon}}
|-
! [[Period 4 element|4]]
| {{element cell image|32|Germanium|Ge| |Solid|Metalloid|Primordial|image=Polycrystalline-germanium.jpg|image caption=Polycrystallline germanium}}
|-
! [[Period 5 element|5]]
| {{element cell image|50|Tin|Sn| |Solid|Other metal|Primordial|image=Sn-Alpha-Beta.jpg|image caption=Alpha- and beta-tin, two allotropes of tin}}
|-
! [[Period 6 element|6]]
| {{element cell image|82|Lead|Pb| |Solid|Other metal|Primordial|image=Lead electrolytic and 1cm3 cube.jpg|image caption=Lead crystals}}
|-
! [[Period 7 element|7]]
| {{element cell image|114|Flerovium|Fl| |Unknown phase|Other metal|Synthetic}}
|-
| colspan="2"|
----
''Legend''
{| style="text-align:center; border:0; margin:1em auto;"
|-
| style="border:{{element color|Primordial}}; background:{{Element color|table mark}};" | [[primordial element]]
|-
| style="border:{{element color|Synthetic}}; background:{{Element color|table mark}};" | [[synthetic element]]
|}
|}

The '''carbon group''' is a [[group (periodic table)|periodic table group]] consisting of [[carbon]] (C), [[silicon]] (Si), [[germanium]] (Ge), [[tin]] (Sn), [[lead]] (Pb), and [[flerovium]] (Fl). It lies within the [[p-block]].

In modern [[International Union of Pure and Applied Chemistry|IUPAC]] notation, it is called '''group&nbsp;14'''. In the field of [[Semiconductor#Physics of semiconductors|semiconductor physics]], it is still universally called '''group&nbsp;IV'''. The group is also known as the '''tetrels''' (from the Greek word ''tetra'', which means four), stemming from the Roman numeral IV in the group name, or (not coincidentally) from the fact that these elements have four [[valence electron]]s (see below). They are also known as the '''crystallogens'''<ref name=crystal>{{cite journal |last1=Liu |first1=Ning |last2=Lu |first2=Na |first3=Yan |last3=Su |first4=Pu |last4=Wang |first5=Xie |last5=Quan |date=2019 |title=Fabrication of g-C<sub>3</sub>N<sub>4</sub>/Ti<sub>3</sub>C<sub>2</sub> composite and its visible-light photocatalytic capability for ciprofloxacin degradation |journal=Separation and Purification Technology |volume=211 |pages=782–789 |doi=10.1016/j.seppur.2018.10.027 |url=https://www.researchgate.net/publication/317583451 |access-date=17 August 2019}}</ref> or '''adamantogens'''.<ref>W. B. Jensen, [http://www.che.uc.edu/jensen/w.%20b.%20jensen/reprints/081.%20Periodic%20Table.pdf The Periodic Law and Table] {{Webarchive|url=https://web.archive.org/web/20201110113324/http://www.che.uc.edu/jensen/w.%20b.%20jensen/reprints/081.%20Periodic%20Table.pdf |date=2020-11-10 }}.</ref>

==Characteristics==
===Chemical===
Like other groups, the members of this family show patterns in [[electron configuration]], especially in the outermost shells, resulting in trends in chemical behavior:

{| class="wikitable" style="white-space:nowrap;"
|-
!''[[Atomic number|Z]]'' !! [[Chemical element|Element]] !! Electrons per [[Electron shell|shell]]
|-
| 6 || [[Carbon]] || 2, 4
|-
| 14 || [[Silicon]] || 2, 8, 4
|-
| 32 || [[Germanium]] || 2, 8, 18, 4
|-
| 50 || [[Tin]] || 2, 8, 18, 18, 4
|-
| 82 || [[Lead]] || 2, 8, 18, 32, 18, 4
|-
| 114 || [[Flerovium]] || 2, 8, 18, 32, 32, 18, 4<br/>(predicted)
|}

Each of the [[chemical element|elements]] in this group has 4 [[electron]]s in its outer [[electron shell|shell]]. An isolated, neutral group 14 atom has the ns<sup>2</sup>&nbsp;np<sup>2</sup> configuration in the ground state. These elements, especially [[carbon]] and [[silicon]], have a strong propensity for [[covalent bond]]ing, which usually brings the outer shell [[octet rule|to eight electrons]]. Bonds in these elements often lead to [[orbital hybridisation|hybridisation]] where distinct [[azimuthal quantum number|s and p characters]] of the orbitals are erased. For [[single bond]]s, a typical arrangement has [[tetrahedral molecular geometry|four pairs of sp<sup>3</sup> electrons]], although other cases exist too, such as three sp<sup>2</sup> pairs in [[graphene]] and graphite. Double bonds are characteristic for carbon ([[alkene]]s, {{CO2|link=yes}}...); the same for [[pi bond|π-systems]] in general. The tendency to lose electrons increases as the size of the [[atom]] increases, as it does with increasing atomic number.
Carbon alone forms negative [[ion]]s, in the form of [[carbide]] (C<sup>4−</sup>) ions.
Silicon and [[germanium]], both [[metalloid]]s, each can form +4 ions.
[[Tin]] and [[lead]] both are [[metal]]s, while flerovium is a synthetic, [[radioactive]] (its half life is very short, only 1.9 seconds) element that may have a few [[noble gas]]-like properties, though it is still most likely a post-transition metal. Tin and lead are both capable of forming +2 ions. Although tin is chemically a metal, [[α-tin|its α allotrope]] looks more like germanium than like a metal and it is a poor electric conductor.

Among main group (groups 1, 2, 13–17) alkyl derivatives QR<sub>''n''</sub>, where ''n'' is the standard bonding number for Q (''see'' [[IUPAC nomenclature of inorganic chemistry|lambda convention]]), the group 14 derivatives QR<sub>4</sub> are notable in being electron-precise: they are neither electron-deficient (having fewer electrons than an octet and tending to be Lewis acidic at Q and usually existing as oligomeric clusters or adducts with Lewis bases) nor electron-excessive (having lone pair(s) at Q and tending to be Lewis basic at Q).  As a result, the group 14 alkyls have low chemical reactivity relative to the alkyl derivatives of other groups.  In the case of carbon, the high bond dissociation energy of the [[C–C bond]] and lack of electronegativity difference between the central atom and the alkyl ligands render the saturated alkyl derivatives, the [[alkane]]s, particularly inert.<ref>{{Cite book |last=Crabtree |first=Robert H. |title=The organometallic chemistry of the transition metals |date=2005 |publisher=Wiley |isbn=978-0-471-66256-3 |edition=4 |location=Hoboken, N.J |pages=418}}</ref>

Carbon forms tetrahalides with all the [[halogen]]s. Carbon also forms [[carbon oxides|many oxides]] such as [[carbon monoxide]], [[carbon suboxide]], and [[carbon dioxide]]. Carbon forms [[Carbon disulfide|a disulfide]] an [[Carbon diselenide|a diselenide]].<ref>{{Citation|url = http://www.webelements.com/carbon/compounds.html|title = Carbon compounds|access-date = January 24, 2013}}</ref>

Silicon forms several hydrides; two of them are [[silane|SiH<sub>4</sub>]] and [[disilane|Si<sub>2</sub>H<sub>6</sub>]]. Silicon forms tetrahalides with fluorine ([[Silicon tetrafluoride|SiF<sub>4</sub>]]), chlorine ([[Silicon tetrachloride|SiCl<sub>4</sub>]]), bromine ([[Silicon tetrabromide|SiBr<sub>4</sub>]]), and iodine ([[Silicon tetraiodide|SiI<sub>4</sub>]]). Silicon also forms [[silicon dioxide|a dioxide]] and [[silicon disulfide|a disulfide]].<ref>{{Citation|url = http://www.webelements.com/silicon/compounds.html|title = Silicon compounds|access-date = January 24, 2013}}</ref> [[Silicon nitride]] has the formula Si<sub>3</sub>N<sub>4</sub>.<ref name="The Elements"/>

Germanium forms five hydrides. The first two germanium hydrides are [[germane|GeH<sub>4</sub>]] and [[digermane|Ge<sub>2</sub>H<sub>6</sub>]]. Germanium forms tetrahalides with all halogens except astatine and forms dihalides with all halogens except bromine and astatine. Germanium bonds to all natural single chalcogens except polonium, and forms dioxides, disulfides, and diselenides. [[Germanium nitride]] has the formula Ge<sub>3</sub>N<sub>4</sub>.<ref>{{Citation|url = http://www.webelements.com/germanium/compounds.html|title = Germanium compounds|access-date = January 24, 2013}}</ref>

Tin forms two hydrides: [[stannane|SnH<sub>4</sub>]] and [[distannane|Sn<sub>2</sub>H<sub>6</sub>]]. Tin forms dihalides and tetrahalides with all halogens except astatine. Tin forms monochalcogenides with naturally occurring chalcogens except polonium, and forms dichalcogenides with naturally occurring chalcogens except polonium and tellurium.<ref>{{Citation|url = http://www.webelements.com/tin/compounds.html|title = Tin compounds|access-date = January 24, 2013}}</ref>

Lead forms one hydride, which has the formula [[plumbane|PbH<sub>4</sub>]]. Lead forms dihalides and tetrahalides with fluorine and chlorine, and forms [[Lead(II) bromide|a dibromide]] and [[Lead(II) iodide|a diiodide]], although the tetrabromide and tetraiodide of lead are unstable. Lead forms [[Lead oxide|four oxides]], [[Lead(II) sulfide|a sulfide]], [[Lead selenide|a selenide]], and [[Lead telluride|a telluride]].<ref>{{Citation|url = http://www.webelements.com/lead/compounds.html|title = Lead compounds|access-date = January 24, 2013}}</ref>

There are no known compounds of flerovium.<ref>{{Citation|url = http://www.webelements.com/flerovium/compounds.html|title = Flerovium compounds|access-date = January 24, 2013}}</ref>

===Physical===
The [[boiling point]]s of the carbon group tend to get lower with the heavier elements. At [[standard pressure]], carbon, the lightest carbon group element, [[sublimation (phase transition)|sublimes]] at 3825&nbsp;°C. Silicon's boiling point is 3265&nbsp;°C, germanium's is 2833&nbsp;°C, tin's is 2602&nbsp;°C, and lead's is 1749&nbsp;°C. Flerovium is predicted to boil at −60&nbsp;°C.<ref name=gaseous>
Archived at [https://ghostarchive.org/varchive/youtube/20211211/F1sCiP72SY4 Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20170430135923/https://www.youtube.com/watch?v=F1sCiP72SY4&feature=youtu.be Wayback Machine]{{cbignore}}: {{cite web
|title=Discovering Superheavy Elements
|url=https://www.youtube.com/watch?v=F1sCiP72SY4
|first=Yu. Ts.
|last=Oganessian
|author-link=Yuri Oganessian
|publisher=[[Oak Ridge National Laboratory]]
|date=27 January 2017
|access-date=21 April 2017
}}{{cbignore}}</ref><ref name=EB>
{{cite web
|last=Seaborg |first=G. T.
|title=Transuranium element
|url=https://www.britannica.com/EBchecked/topic/603220/transuranium-element
|publisher=[[Encyclopædia Britannica]]
|access-date=2010-03-16
}}</ref> The [[melting point]]s of the carbon group elements have roughly the same trend as their boiling points. Silicon melts at 1414&nbsp;°C, germanium melts at 939&nbsp;°C, tin melts at 232&nbsp;°C, and lead melts at 328&nbsp;°C.<ref name="Table">{{Citation|last = Jackson|first = Mark|title = Periodic Table Advanced|year = 2001}}</ref>

Carbon's crystal structure is [[hexagonal crystal system|hexagonal]]; at high pressures and temperatures it forms [[diamond]] (see below). Silicon and germanium have [[diamond cubic]] crystal structures, as does tin at low temperatures (below 13.2&nbsp;°C). Tin at room temperature has a [[tetragonal crystal system|tetragonal]] crystal structure. Lead has a [[face-centered cubic]] crystal structure.<ref name = "Table"/>

The [[density|densities]] of the carbon group elements tend to increase with increasing atomic number. Carbon has a density of 2.26 g·cm<sup>−3</sup>; silicon, 2.33 g·cm<sup>−3</sup>; germanium, 5.32 g·cm<sup>−3</sup>; tin, 7.26 g·cm<sup>−3</sup>; lead, 11.3 g·cm<sup>−3</sup>.<ref name = "Table"/>

The [[atomic radii]] of the carbon group elements tend to increase with increasing atomic number. Carbon's atomic radius is 77 [[picometers]], silicon's is 118 picometers, germanium's is 123 picometers, tin's is 141 picometers, and lead's is 175 picometers.<ref name = "Table"/>

====Allotropes====
{{main|Allotropes of carbon}}
Carbon has multiple [[allotrope]]s. The most common is [[graphite]], which is carbon in the form of stacked sheets. Another form of carbon is [[diamond]], but this is relatively rare. [[Amorphous carbon]] is a third allotrope of carbon; it is a component of [[soot]]. Another allotrope of carbon is a [[fullerene]], which has the form of sheets of carbon atoms folded into a sphere. A fifth allotrope of carbon, discovered in 2003, is called [[graphene]], and is in the form of a layer of carbon atoms arranged in a honeycomb-shaped formation.<ref name = "The Elements"/><ref>{{Citation|url = http://www.graphene.manchester.ac.uk/|title = Graphene|access-date = 20 January 2013}}</ref><ref>{{Citation|url=http://www.webelements.com/carbon/allotropes.html |title=Carbon:Allotropes |access-date=20 January 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130117081035/http://www.webelements.com/carbon/allotropes.html |archive-date=2013-01-17 }}</ref>

Silicon has two known allotropes that exist at room temperature. These allotropes are known as the amorphous and the crystalline allotropes. The amorphous allotrope is a brown powder. The crystalline allotrope is gray and has a metallic [[Lustre (mineralogy)|luster]].<ref>{{Citation|last = Gagnon|first = Steve|url = http://education.jlab.org/itselemental/ele014.html|title = The Element Silicon|access-date = January 20, 2013}}</ref>

Tin has two allotropes: α-tin, also known as gray tin, and β-tin. Tin is typically found in the β-tin form, a silvery metal. However, at standard pressure, β-tin converts to α-tin, a gray powder, at temperatures below {{convert|13.2|C}}. This can cause tin objects in cold temperatures to crumble to gray powder in a process known as [[tin pest]] or tin rot.<ref name = "The Elements"/><ref name = "The Disappearing Spoon"/>

===Nuclear===
At least two of the carbon group elements (tin and lead) have [[magic nucleus|magic nuclei]], meaning that these elements are more common and more stable than elements that do not have a magic nucleus.<ref name="The Disappearing Spoon"/>

====Isotopes====
There are 15 known [[isotopes of carbon]]. Of these, three are naturally occurring. The most common is [[stable isotope|stable]] [[carbon-12]], followed by stable [[carbon-13]].<ref name="Table"/> [[Carbon-14]] is a natural radioactive isotope with a half-life of 5,730 years.<ref name = "Nature's Building Blocks"/>

23 [[isotopes of silicon]] have been discovered. Five of these are naturally occurring. The most common is stable silicon-28, followed by stable silicon-29 and stable silicon-30. Silicon-32 is a radioactive isotope that occurs naturally as a result of radioactive decay of [[actinides]], and via [[spallation]] in the upper atmosphere. Silicon-34 also occurs naturally as the result of radioactive decay of actinides.<ref name = "Nature's Building Blocks"/>

32 [[isotopes of germanium]] have been discovered. Five of these are naturally occurring. The most common is the stable germanium-74, followed by stable germanium-72, stable germanium-70, and stable germanium-73. Germanium-76 is a [[primordial nuclide|primordial radioisotope]].<ref name = "Nature's Building Blocks"/>

40 [[isotopes of tin]] have been discovered. 14 of these occur in nature. The most common is tin-120, followed by tin-118, tin-116, tin-119, tin-117, tin-124, tin-122, tin-112, and tin-114: all of these are stable. Tin also has four radioisotopes that occur as the result of the radioactive decay of uranium. These isotopes are tin-121, tin-123, tin-125, and tin-126.<ref name = "Nature's Building Blocks"/>

38 [[isotopes of lead]] have been discovered. 9 of these are naturally occurring. The most common isotope is lead-208, followed by lead-206, lead-207, and lead-204: all of these are stable. 5 isotopes of lead occur from the radioactive decay of uranium and thorium. These isotopes are lead-209, lead-210, lead-211, lead-212 and lead-214.<ref name = "Nature's Building Blocks"/>

6 [[isotopes of flerovium]] (flerovium-284, flerovium-285, flerovium-286, flerovium-287, flerovium-288, and flerovium-289) have been discovered, all from human synthesis. Flerovium's most stable isotope is flerovium-289, which has a half-life of 2.6 seconds.<ref name = "Nature's Building Blocks"/>

==Occurrence==
Carbon accumulates as the result of [[stellar fusion]] in most stars, even small ones.<ref name = "The Disappearing Spoon"/> Carbon is present in the Earth's crust in concentrations of 480 parts per million, and is present in [[seawater]] at concentrations of 28 parts per million. Carbon is present in the atmosphere in the form of [[carbon monoxide]], [[carbon dioxide]], and [[methane]]. Carbon is a key constituent of [[carbonate minerals]], and is in [[hydrogen carbonate]], which is common in seawater. Carbon forms 22.8% of a typical human.<ref name = "Nature's Building Blocks"/>

Silicon is present in the Earth's crust at concentrations of 28%, making it the second most abundant element there. Silicon's concentration in seawater can vary from 30 parts per billion on the surface of the ocean to 2000 parts per billion deeper down. Silicon dust occurs in trace amounts in Earth's atmosphere. [[Silicate minerals]] are the most common type of mineral on earth. Silicon makes up 14.3 parts per million of the human body on average.<ref name = "Nature's Building Blocks"/> Only the largest stars produce silicon via stellar fusion.<ref name = "The Disappearing Spoon"/>

Germanium makes up 2 parts per million of the Earth's crust, making it the 52nd most abundant element there. On average, germanium makes up 1 part per million of [[soil]]. Germanium makes up 0.5 parts per trillion of seawater. [[Organogermanium chemistry|Organogermanium compounds]] are also found in seawater. Germanium occurs in the human body at concentrations of 71.4 parts per billion. Germanium has been found to exist in some very faraway stars.<ref name = "Nature's Building Blocks"/>

Tin makes up 2 parts per million of the Earth's crust, making it the 49th most abundant element there. On average, tin makes up 1 part per million of soil. Tin exists in seawater at concentrations of 4 parts per trillion. Tin makes up 428 parts per billion of the human body. [[Tin(IV) oxide]] occurs at concentrations of 0.1 to 300 parts per million in soils.<ref name = "Nature's Building Blocks"/> Tin also occurs in concentrations of one part per thousand in [[igneous rock]]s.<ref>{{Citation|url = https://www.britannica.com/EBchecked/topic/596431/tin-Sn|title = tin (Sn)|year = 2013|access-date = February 24, 2013|publisher = [[Encyclopædia Britannica]]}}</ref>

Lead makes up 14 parts per million of the Earth's crust, making it the 36th most abundant element there. On average, lead makes up 23 parts per million of soil, but the concentration can reach 20000 parts per million (2 percent) near old lead mines. Lead exists in seawater at concentrations of 2 parts per trillion. Lead makes up 1.7 parts per million of the human body by weight. Human activity releases more lead into the environment than any other metal.<ref name = "Nature's Building Blocks"/>

Flerovium doesn't occur in nature at all, so it only exists in [[particle accelerators]] with a few atoms at a time.<ref name = "Nature's Building Blocks"/>

==History==
=== Discoveries and uses in antiquity ===
[[Carbon]], [[tin]], and [[lead]] are a few of the elements well known in the ancient world, together with [[sulfur]], [[iron]], [[copper]], [[mercury (element)|mercury]], [[silver]], and [[gold]].<ref>{{Citation|url = http://www.chemicalelements.com|title = Chemical Elements|access-date = 20 January 2013}}</ref>

Silicon as silica in the form of rock crystal was familiar to the predynastic Egyptians, who used it for beads and small vases; to the early Chinese; and probably to many others of the ancients. The manufacture of glass containing silica was carried out both by the Egyptians&nbsp;– at least as early as 1500 BCE&nbsp;– and by the [[Phoenicians]]. Many of the naturally occurring compounds or [[silicate minerals]] were used in various kinds of mortar for construction of dwellings by the earliest people.

The origins of tin seem to be lost in history. It appears that bronzes, which are alloys of copper and tin, were used by prehistoric man some time before the pure metal was isolated. Bronzes were common in early Mesopotamia, the Indus Valley, Egypt, Crete, Israel, and Peru. Much of the tin used by the early Mediterranean peoples apparently came from the [[Scilly Isles]] and Cornwall in the British Isles,<ref>{{Citation|url = https://www.britannica.com/EBchecked/topic/596431/tin|title = Online Encyclopædia Britannica, Tin}}</ref> where mining of the metal dates from about 300–200 BCE. Tin mines were operating in both the Inca and Aztec areas of South and Central America before the Spanish conquest.

Lead is mentioned often in early Biblical accounts. The [[Babylonians]] used the metal as plates on which to record inscriptions. The [[Ancient Rome|Romans]] used it for tablets, water pipes, coins, and even cooking utensils; indeed, as a result of the last use, lead poisoning was recognized in the time of [[Augustus Caesar]]. The compound known as [[white lead]] was apparently prepared as a decorative pigment at least as early as 200 BCE.

===Modern discoveries===
[[amorphous silicon|Amorphous elemental silicon]] was first obtained pure in 1824 by the Swedish chemist [[Jöns Jacob Berzelius]]; impure silicon had already been obtained in 1811. [[crystalline silicon|Crystalline elemental silicon]] was not prepared until 1854, when it was obtained as a product of electrolysis.

Germanium is one of three elements the existence of which was predicted in 1869 by the Russian chemist [[Dmitri Mendeleev]] when he first devised his periodic table. However, the element was not actually discovered for some time. In September 1885, a miner discovered a mineral sample in a silver mine and gave it to the mine manager, who determined that it was a new mineral and sent the mineral to [[Clemens Winkler|Clemens A. Winkler]]. Winkler realized that the sample was 75% silver, 18% sulfur, and 7% of an undiscovered element. After several months, Winkler isolated the element and determined that it was element 32.<ref name = "Nature's Building Blocks"/>

The first attempt to discover flerovium (then referred to as "element 114") was in 1969, at the [[Joint Institute for Nuclear Research]], but it was unsuccessful. In 1977, researchers at the Joint Institute for Nuclear Research bombarded [[plutonium-244]] atoms with [[calcium-48]], but were again unsuccessful. This nuclear reaction was repeated in 1998, this time successfully.<ref name = "Nature's Building Blocks"/>

===Etymologies===
*'''Carbon''' comes from the Latin word ''carbo'', meaning "charcoal".
*'''Silicon''' comes from the Latin word ''silex'' (or ''silicis''), meaning "flint".
*'''Germanium''' comes from the Latin word ''Germania'', the Latin name for Germany, which is the country where germanium was discovered.
*'''Stannum''' comes from the Latin word ''stannum'', meaning "tin", from or related to Celtic ''staen''.
::- The common name for stannum in English is ''tin'', inherited directly from [[Old English]]. Possibly of common origin with ''stannum'' and ''staen''.
*'''Plumbum''' comes from the Latin word ''plumbum'' meaning lead.
::- The common name for plumbum in English is ''lead'', inherited directly from Old English.<ref name="Nature's Building Blocks" />
*'''Flerovium''' was named after [[Georgy Flyorov]] and his Institute.

==Applications==
Carbon is most commonly used in its [[amorphous]] form. In this form, carbon is used for [[steelmaking]], as [[carbon black]], as a filling in [[tires]], in [[respirators]], and as [[activated charcoal]]. Carbon is also used in the form of [[graphite]], for example as the lead in [[pencils]]. [[Diamond]], another form of carbon, is commonly used in jewelry.<ref name = "Nature's Building Blocks"/> [[Carbon fibers]] are used in numerous applications, such as [[satellite]] struts, because the fibers are highly strong yet elastic.<ref name = "Structure of Matter">{{Citation|last =  Galan|first = Mark|title = Structure of Matter|year = 1992| publisher=Time-Life |isbn=0-809-49663-1}}</ref>

[[Silicon dioxide]] has a wide variety of applications, including [[toothpaste]], construction fillers, and silica is a major component of [[glass]]. 50% of pure silicon is devoted to the manufacture of metal [[alloys]]. 45% of silicon is devoted to the manufacture of [[silicone]]s. Silicon is also commonly used in [[semiconductor]]s since the 1950s.<ref name = "The Disappearing Spoon"/><ref name="Structure of Matter"/>

Germanium was used in semiconductors until the 1950s, when it was replaced by silicon.<ref name = "The Disappearing Spoon"/> Radiation detectors contain germanium. [[Germanium dioxide]] is used in [[fiber optics]] and wide-angle camera lenses. A small amount of germanium mixed with [[silver]] can make silver [[tarnish]]-proof. The resulting alloy is known as [[argentium sterling silver]].<ref name = "Nature's Building Blocks"/>

[[Solder]] is the most important use of tin; 50% of all tin produced goes into this application. 20% of all tin produced is used in [[tin plate]]. 20% of tin is used by the [[chemical industry]]. Tin is a constituent of numerous alloys, including [[pewter]]. [[Tin(IV) oxide]] has been commonly used in [[ceramic]]s for thousands of years. [[Cobalt stannate]] is a tin compound which is used as a [[cerulean blue]] [[pigment]].<ref name = "Nature's Building Blocks"/>

80% of all lead produced goes into [[Lead–acid battery|lead–acid batteries]]. Other applications for lead include weights, pigments, and shielding against radioactive materials. Lead was historically used in gasoline in the form of [[tetraethyllead]], but this application has been discontinued due to concerns of toxicity.<ref>{{Citation|last = Blum|first = Deborah|title = The Poisoner's Handbook|year = 2010}}<!-- ISBN=1-101-4288-x ?--></ref>

==Production==
Carbon's allotrope diamond is produced mostly by [[Russia]], [[Botswana]], [[Congo (area)|Congo]], [[Canada]], [[South Africa]], and [[India]]. 80% of all [[synthetic diamond]]s are produced by Russia. China produces 70% of the world's graphite. Other graphite-mining countries are [[Brazil]], Canada, and [[Mexico]].<ref name = "Nature's Building Blocks"/>

Silicon can be produced by heating silica with carbon.<ref name = "Structure of Matter"/>

There are some germanium ores, such as [[germanite]], but these are not mined on account of being rare. Instead, germanium is extracted from the ores of metals such as [[zinc]]. In Russia and [[China]], germanium is also separated from coal deposits. Germanium-containing ores are first treated with [[chlorine]] to form [[germanium tetrachloride]], which is mixed with hydrogen gas. Then the germanium is further refined by [[zone refining]]. Roughly 140 metric tons of germanium are produced each year.<ref name = "Nature's Building Blocks"/>

Mines output 300,000 metric tons of tin each year. China, [[Indonesia]], [[Peru]], [[Bolivia]], and Brazil are the main producers of tin. The method by which tin is produced is to heat the tin mineral [[cassiterite]] (SnO<sub>2</sub>) with [[coke (fuel)|coke]].<ref name = "Nature's Building Blocks"/>

The most commonly mined lead ore is [[galena]] (lead sulfide). 4 million metric tons of lead are newly mined each year, mostly in China, [[Australia]], the [[United States]], and Peru. The ores are mixed with coke and [[limestone]] and [[roasting (metallurgy)|roasted]] to produce pure lead. Most lead is recycled from [[lead batteries]]. The total amount of lead ever mined by humans amounts to 350 million metric tons.<ref name = "Nature's Building Blocks"/>

==Biological role==
Carbon is a key element to all known life. It is in all organic compounds, for example, [[DNA]], [[steroid]]s, and [[protein]]s.<ref name = "The Elements">{{Citation|last = Gray|first = Theodore|title = The Elements|year = 2011}}</ref> Carbon's importance to life is primarily due to its ability to form numerous bonds with other elements.<ref name="The Disappearing Spoon">{{Citation|last = Kean|first = Sam|title = The Disappearing Spoon|year = 2011}}</ref> There are 16 kilograms of carbon in a typical 70-kilogram human.<ref name="Nature's Building Blocks"/>

[[Silicon-based life]]'s feasibility is commonly discussed. However, it is less able than carbon to form elaborate rings and chains.<ref name = "The Elements"/> Silicon in the form of [[silicon dioxide]] is used by [[diatoms]] and [[sea sponges]] to form their [[cell walls]] and [[skeletons]]. Silicon is essential for [[bone]] growth in chickens and rats and may also be essential in humans. Humans consume on average between 20 and 1200 [[milligrams]] of silicon per day, mostly from [[cereals]]. There is 1 gram of silicon in a typical 70-kilogram human.<ref name = "Nature's Building Blocks">{{Citation|last = Emsley|first = John|title = Nature's Building Blocks|year = 2011}}</ref>

A biological role for germanium is not known, although it does stimulate [[metabolism]]. In 1980, germanium was reported by [[Kazuhiko Asai]] to benefit health, but the claim has not been proven. Some plants take up germanium from the soil in the form of [[germanium oxide]].{{clarify|date=August 2019|reason=Ge(II) or Ge(IV)?}} These plants, which include [[Food grain|grain]]s and [[vegetables]] contain roughly 0.05 parts per million of germanium. The estimated human intake of germanium is 1 milligram per day. There are 5 milligrams of germanium in a typical 70-kilogram human.<ref name="Nature's Building Blocks"/>

Tin has been shown to be essential for proper growth in rats, but there is, as of 2013, no evidence to indicate that humans need tin in their diet. Plants do not require tin. However, plants do collect tin in their [[root]]s. [[Wheat]] and [[maize]] contain 7 and 3 parts per million respectively. However, the level of tin in plants can reach 2000 parts per million if the plants are near a tin [[smelter]]. On average, humans consume 0.3 milligrams of tin per day. There are 30 milligrams of tin in a typical 70-kilogram human.<ref name="Nature's Building Blocks"/>

Lead has no known biological role, and is in fact highly [[toxic]], but some [[microbes]] are able to survive in lead-contaminated environments. Some plants, such as [[cucumber]]s contain up to tens of parts per million of lead. There are 120 milligrams of lead in a typical 70-kilogram human.<ref name="Nature's Building Blocks"/>

Flerovium has no biological role and instead is found and made only in particle accelerators.

===Toxicity===
Elemental carbon is not generally toxic, but many of its compounds are, such as [[carbon monoxide]] and [[hydrogen cyanide]]. However, carbon dust can be dangerous because it lodges in the lungs in a manner similar to [[asbestos]].<ref name = "Nature's Building Blocks"/>

Silicon minerals are not typically poisonous. However, silicon dioxide dust, such as that emitted by [[volcanoes]] can cause adverse health effects if it enters the lungs.<ref name = "The Disappearing Spoon"/>

Germanium can interfere with such [[enzymes]] as [[lactate dehydrogenase]] and [[alcohol dehydrogenase]]. Organic germanium compounds are more toxic than inorganic germanium compounds. Germanium has a low degree of [[mouth|oral]] toxicity in animals. Severe germanium poisoning can cause death by [[respiratory paralysis]].<ref>{{Citation|url=http://www.food.gov.uk/multimedia/pdfs/evm_germanium.pdf%20 |title=Risk Assessment |year=2003 |access-date=January 19, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20120112060340/http://www.food.gov.uk/multimedia/pdfs/evm_germanium.pdf |archive-date=January 12, 2012 }}</ref>

Some tin compounds are toxic to ingest, but most inorganic compounds of tin are considered nontoxic. Organic tin compounds, such as [[trimethyltin]] and [[triethyltin]] are highly toxic, and can disrupt metabolic processes inside cells.<ref name="Nature's Building Blocks"/>

Lead and its compounds, such as [[lead acetate]]s are highly toxic. [[Lead poisoning]] can cause [[headaches]], stomach pain, [[constipation]], and [[gout]].<ref name = "Nature's Building Blocks"/>

Flerovium is too radioactive to test if it's toxic or not although its high radioactivity alone would be toxic.

==References==
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{{Navbox periodic table}}
{{Carbon group elements}}

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{{DEFAULTSORT:Carbon Group}}
[[Category:Groups (periodic table)]]