The ionic radius, rion, is a measure of the size of an ion in a crystal lattice. Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances The covalent radius, r cov is a measure of the size of Atom which forms part of a Covalent bond. Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances Van der Waals Volume The van der Waals volume, V, also called the atomic volume or molecular volume, is the atomic property most directly An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. It is measured in either picometres (pm) or Angstrom (Å), with 1 Å = 100 pm. A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth An ångström or angstrom (symbol Å) (ˈɔːŋstrəm Swedish: ˈɔ̀ŋstrœm is an internationally recognized non- SI unit of length equal Typical values range from 30 pm (0. 3 Å) to over 200 pm (2 Å).
The concept of ionic radius was developed independently by Goldschmidt and Pauling in the 1920s to summarize the data being generated by the (then) new technique of X-ray crystallography: it is Pauling's approach which proved to be the more influential. Linus Carl Pauling (February 28 1901 – August 19 1994 was an American Scientist, Peace activist, Author and educator. X-ray crystallography is a method of determining the arrangement of Atoms within a Crystal, in which a beam of X-rays strikes a crystal and scatters X-ray crystallography can readily give the length of the side of the unit cell of a crystal, but it is much more difficult (in most cases impossible, even with more modern techniques) to distinguish a boundary between two ions. In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. For example, it can be readily determined that each side of the unit cell of sodium chloride is 564. For sodium chloride in the diet see Salt. Sodium chloride, also known as common salt, table salt, or Halite, is a 02 pm in length, and that this length is twice the distance between the centre of a sodium ion and the centre of a chloride ion:
-
- 2[rion(Na+) + rion(Cl−)] = 564. The chloride Ion is formed when the element Chlorine picks up one Electron to form an Anion (negatively-charged ion Cl&minus 02 pm
However, it is not apparent what proportion of this distance is due to the size of the sodium ion and what proportion is due to the size of the chloride ion. By comparing many different compounds, and with a certain amount of chemical intuition, Pauling decided to assign a radius of 140 pm to the oxide ion O2−, at which point he was able to calculate the radii of the other ions by subtraction. An oxide is a Chemical compound containing at least one Oxygen atom as well as at least one other element [1]
A major review of crystallographic data led to the publication of a revised set of ionic radii in 1976,[2] and these are preferred to Pauling's original values. Some sources have retained Pauling's reference of rion(O2−) = 140 pm, while other sources prefer to list "effective" ionic radii based on rion(O2−) = 126 pm. The latter values are thought to be a more accurate approximation to the "true" relative sizes of anions and cations in ionic crystals. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge An ionic crystal is a Crystal consisting of Ions bound together by their Electrostatic attraction
The ionic radius is not a fixed property of a given ion, but varies with coordination number, spin state and other parameters. The coordination number of an atom in a molecule or a crystal is the number of its nearest neighbours Nevertheless, ionic radius values are sufficiently transferable to allow periodic trends to be recognized. This page is about transferability in chemistry Transferability in economics also exists Periodicity is the quality of occurring at regular intervals or periods (in Time or Space) and can occur in different contexts A Clock marks As with other types of atomic radius, ionic radii increase on descending a group. Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in Ionic size (for the same ion) also increases with increasing coordination number, and an ion in a high-spin state will be larger than the same ion in a low-spin state. Anions (negatively charged) are almost invariable larger than cations (positively charged), although the fluorides of some alkali metals are rare exceptions. Fluoride is the reduced form of Fluorine. Both organic and Inorganic compounds containing the element fluorine are considered fluorides Trends The alkali metals show a number of trends when moving down the group - for instance decreasing electronegativity increasing reactivity and decreasing melting and boiling In general, ionic radius decreases with increasing positive charge and increases with increasing negative charge.
| X− |
NaX |
AgX |
| F |
464 |
492 |
| Cl |
564 |
555 |
| Br |
598 |
577 |
| Unit cell parameters (in pm, equal to two M–X bond lengths) for sodium and silver halides. A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth All compounds crystallize in the NaCl structure. |
An "anomalous" ionic radius in a crystal is often a sign of significant covalent character in the bonding. No bond is completely ionic, and some supposedly "ionic" compounds, especially of the transition metals, are particularly covalent in character. In Chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings It commonly refers to any element in This is illustrated by the unit cell parameters for sodium and silver halides in the table. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen A halide is a Binary compound, of which one part is a Halogen Atom and the other part is an element or radical that is less On the basis of the fluorides, one would say that Ag+ is larger than Na+, but on the basis of the chlorides and bromides the opposite appears to be true. The chloride Ion is formed when the element Chlorine picks up one Electron to form an Anion (negatively-charged ion Cl&minus A bromide Ion is a Bromine atom with charge of −1 Compounds with bromine in formal Oxidation state −1 are called bromides [3] This is because the greater covalent character of the bonds in AgCl and AgBr reduces the bond length and hence the apparent ionic radius of Ag+, an effect which is not present in the halides of the more electropositive sodium, nor in silver fluoride in which the fluoride ion is relatively unpolarizable. " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons Polarizability is the relative tendency of a charge distribution like the Electron cloud of an Atom or Molecule, to be distorted from its normal shape
Ionic radii 6 coordinate unless marked
(e. g +34). ls = low spin, hs= high spin. [2]
| Atomic No |
Element |
|
charge ionic radius pm |
| 3 |
Lithium |
Li |
|
| 4 |
Beryllium |
Be |
|
| 5 |
Boron |
B |
|
| 6 |
Carbon |
C |
|
| 7 |
Nitrogen |
N |
|
| 8 |
Oxygen |
O |
|
| 9 |
Fluorine |
F |
|
| 11 |
Sodium |
Na |
|
| 12 |
Magnesium |
Mg |
|
| 13 |
Aluminum |
Al |
| +3 |
53. A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Beryllium (bəˈrɪliəm is a Chemical element with the symbol Be and Atomic number 4 Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Fluorine, fluorum meaning "to flow" is the Chemical element with the symbol F and Atomic number 9 Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 WikipediaNaming 5 |
|
| 14 |
Silicon |
Si |
|
| 15 |
Phosphorus |
P |
|
| 16 |
Sulfur |
S |
|
| 17 |
Chlorine |
Cl |
|
| 19 |
Potassium |
K |
|
| 20 |
Calcium |
Ca |
|
| 21 |
Scandium |
Sc |
| +3 |
74. Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Scandium (ˈskændiəm is a Chemical element that has the symbol Sc and Atomic number 21 5 |
|
| 22 |
Titanium |
Ti |
| +2 |
86 |
| +3 |
67 |
| +4 |
60. Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 5 |
|
| 23 |
Vanadium |
V |
|
| 24 |
Chromium |
Cr |
| +2 |
73 |
ls |
| +2 |
80 |
hs |
| +3 |
61. Vanadium (vəˈneɪdiəm is a Chemical element that has the symbol V and Atomic number 23 Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 5 |
| +4 |
55 |
| +5 |
49 |
| +6 |
44 |
|
| 25 |
Manganese |
Mn |
| +2 |
67 |
| +3 |
58 |
ls |
| +3 |
64. Manganese (ˈmæŋgəniːz is a Chemical element, designated by the symbol Mn. 5 |
hs |
| +4 |
53 |
| +54 |
33 |
| +64 |
25. 5 |
| +7 |
46 |
|
| 26 |
Iron |
Fe |
| +2 |
61 |
ls |
| +2 |
78 |
hs |
| +3 |
55 |
ls |
| +3 |
64. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 5 |
hs |
| +4 |
58. 5 |
| +64 |
25 |
|
| 27 |
Cobalt |
Co |
| +2 |
65 |
ls |
| +2 |
74. Cobalt (ˈkoʊbɒlt is a hard lustrous silver-grey Metal, a Chemical element with symbol Co. 5 |
hs |
| +3 |
54. 5 |
ls |
| +3 |
61 |
hs |
| +4 |
53 |
|
| 28 |
Nickel |
Ni |
| +2 |
69 |
| +3 |
56 |
ls |
| +3 |
60 |
hs |
| +4 |
48 |
ls |
|
| 29 |
Copper |
Cu |
|
| 30 |
Zinc |
Zn |
|
| 31 |
Gallium |
Ga |
|
| 32 |
Germanium |
Ge |
|
| 33 |
Arsenic |
As |
|
| 34 |
Selenium |
Se |
|
| 35 |
Bromine |
Br |
| −1 |
196 |
| +34sq |
59 |
| +54 |
31 |
| +7 |
39 |
|
| 37 |
Rubidium |
Rb |
|
| 38 |
Strontium |
Sr |
|
| 39 |
Yttrium |
Y |
|
| 40 |
Zirconium |
Zr |
|
| 41 |
Niobium |
Nb |
|
| 42 |
Molybdenum |
Mo |
|
| 43 |
Technetium |
Tc |
| +4 |
64. Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Zinc (ˈzɪŋk from Zink is a Metallic Chemical element with the symbol Zn and Atomic number 30 Gallium (ˈgæliəm is a Chemical element that has the symbol Ga and Atomic number 31 Germanium (dʒɚˈmeɪniəm is a Chemical element with the symbol Ge and Atomic number 32 Arsenic (ˈɑrsənɪk is a Chemical element that has the symbol As and Atomic number of 33 Selenium (səˈliniəm is a Chemical element with the Atomic number 34 represented by the chemical symbol Se, an atomic mass of 78 Rubidium (ruːˈbɪdiəm /rəˈbɪdiəm/ is a Chemical element with the symbol Rb and Atomic number 37 Strontium (ˈstrɒntiəm /ˈstrɒnʃiəm/) is a Chemical element with the symbol Sr and the Atomic number 38 Yttrium (ˈɪtriəm is a Chemical element with symbol Y and Atomic number 39 Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 Niobium (naɪˈoʊbiəm or columbium (/kəˈlʌmbiəm/ is a Chemical element that has the symbol Nb and Atomic number 41 Molybdenum (məˈlɪbdənəm from the Greek word for the metal " Lead " is a Group 6 Chemical element with the symbol Mo Technetium (tɛkˈniːʃɪəm is the lightest Chemical element with no Stable isotope. 5 |
| +5 |
60 |
| +7 |
56 |
|
| 44 |
Ruthenium |
Ru |
| +3 |
68 |
| +4 |
62 |
| +5 |
56. Ruthenium (ruːˈθiːniəm is a Chemical element that has the symbol Ru and Atomic number 44 5 |
| +74 |
38 |
| +84 |
36 |
|
| 45 |
Rhodium |
Rh |
| +3 |
66. Rh redirects here For other uses see Rh (disambiguation Rhodium (ˈroʊdiəm is a Chemical element with the symbol 5 |
| +4 |
60 |
| +5 |
55 |
|
| 46 |
Palladium |
Pd |
| +12 |
59 |
| +2 |
86 |
| +3 |
76 |
| +4 |
61. Palladium (pronounced \pəˈleɪdiəm\ is a rare and lustrous silvery-white metal that was discovered in 1803 by William Hyde Wollaston, who named it palladium after the 5 |
|
| 47 |
Silver |
Ag |
|
| 48 |
Cadmium |
Cd |
|
| 49 |
Indium |
In |
|
| 50 |
Tin |
Sn |
|
| 51 |
Antimony |
Sb |
|
| 52 |
Tellurium |
Te |
|
| 53 |
Iodine |
I |
|
| 54 |
Xenon |
Xe |
|
| 55 |
Caesium |
Cs |
|
| 56 |
Barium |
Ba |
|
| 57 |
Lanthanum |
La |
| +3 |
103. Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen Cadmium (ˈkædmiəm is a Chemical element with the symbol Cd and Atomic number 48 Indium (ˈɪndiəm is a Chemical element with chemical symbol In and Atomic number 49 Tin is a Chemical element with the symbol Sn (stannum and Atomic number 50 Antimony (IPA (Received Pronunciation, /ˈæntɪmoʊni/ (US is a Chemical element with the symbol Sb (stibium meaning "mark" and Tellurium (tɪˈlʊəriəm/ /tɛl- is a Chemical element that has the symbol Te and Atomic number 52 Iodine (ˈaɪədaɪn ˈaɪədɪn or /ˈaɪədiːn/ from ιώδης iodes "violet" is a Chemical element that has the symbol I and Atomic Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. Caesium or cesium (ˈsiːziəm is the Chemical element with the symbol Cs and Atomic number 55 Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 Lanthanum (ˈlænθənəm is a Chemical element with the symbol La and Atomic number 57 2 |
|
| 58 |
Cerium |
Ce |
|
| 59 |
Praseodymium |
Pr |
|
| 60 |
Neodymium |
Nd |
| +28 |
129 |
| +3 |
98. Cerium (ˈsɪəriəm is a Chemical element with the symbol Ce and Atomic number 58 Praseodymium (ˌpreɪzioʊˈdɪmiəm or /ˌpreɪsioʊˈdɪmiəm/ is a Chemical element that has the symbol Pr and Atomic number 59 Neodymium (ˌniːoʊˈdɪmiəm is a Chemical element with the symbol Nd and Atomic number 60 3 |
|
| 61 |
Promethium |
Pm |
|
| 62 |
Samarium |
Sm |
| +24 |
122 |
| +3 |
95. Promethium (prəˈmiːθiəm/ /proʊˈmiːθiəm is a Chemical element with the symbol Pm and Atomic number 61 Samarium (səˈmɛəriəm is a Chemical element with the symbol Sm and Atomic number 62 8 |
|
| 63 |
Europium |
Eu |
| +2 |
117 |
| +3 |
94. Europium (jʊˈroʊpiəm is a Chemical element with the symbol Eu and Atomic number 63 7 |
|
| 64 |
Gadolinium |
Gd |
| +3 |
93. Gadolinium (ˌgædəˈlɪniəm is a Chemical element that has the symbol Gd and Atomic number 64 8 |
|
| 65 |
Terbium |
Tb |
| +3 |
92. Terbium (ˈtɝbiəm is a Chemical element with the symbol Tb and Atomic number 65 3 |
| +4 |
76 |
|
| 66 |
Dysprosium |
Dy |
|
| 67 |
Holmium |
Ho |
| +3 |
90. Holmium (ˈhoʊlmiəm is a Chemical element with the symbol Ho and Atomic number 67 1 |
|
| 68 |
Erbium |
Er |
|
| 69 |
Thulium |
Tm |
|
| 70 |
Ytterbium |
Yb |
| +2 |
102 |
| +3 |
86. Erbium (ˈɝbiəm is a Chemical element with the symbol Er and Atomic number 68 Thulium (ˈθjuːliəm is a Chemical element that has the symbol Tm and Atomic number 69 8 |
|
| 71 |
Lutetium |
Lu |
| +3 |
86. Lutetium (ljuːˈtiːʃiəm is a Chemical element with the symbol Lu and Atomic number 71 1 |
|
| 72 |
Hafnium |
Hf |
|
| 73 |
Tantalum |
Ta |
|
| 74 |
Tungsten |
W |
|
| 75 |
Rhenium |
Re |
|
| 76 |
Osmium |
Os |
| +4 |
63 |
| +5 |
57. Hafnium (ˈhæfniəm is a Chemical element that has the symbol Hf and Atomic number 72 Tantalum (ˈtæntələm (formerly tantalium /tænˈtæliəm/ is a Chemical element with the symbol Ta and Atomic number 73 Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 Rhenium (ˈriːniəm is a Chemical element with the symbol Re and Atomic number 75 Osmium (ˈɒzmiəm is a Chemical element that has the symbol Os and Atomic number 76 5 |
| +6 |
54. 5 |
| +7 |
52. 5 |
| +84 |
39 |
|
| 77 |
Iridium |
Ir |
| +3 |
68 |
| +4 |
62. Iridium (ɪˈrɪdiəm is a Chemical element that has the symbol Ir and Atomic number 77 5 |
| +5 |
57 |
|
| 78 |
Platinum |
Pt |
| +2 |
86 |
| +4 |
62. Platinum (ˈplætɪnəm is a Chemical element with the Atomic symbol Pt and an Atomic number of 78 5 |
| +5 |
57 |
|
| 79 |
Gold |
Au |
|
| 80 |
Mercury |
Hg |
|
| 81 |
Thallium |
Tl |
| +1 |
150 |
| +3 |
88. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum Thallium (ˈθæliəm is a Chemical element with the symbol Tl and Atomic number 81 5 |
|
| 82 |
Lead |
Pb |
| +2 |
119 |
| +4 |
77. Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly 5 |
|
| 83 |
Bismuth |
Bi |
|
| 84 |
Polonium |
Po |
|
| 85 |
Astatine |
At |
|
| 87 |
Francium |
Fr |
|
| 88 |
Radium |
Ra |
|
| 89 |
Actinium |
Ac |
|
| 90 |
Thorium |
Th |
|
| 91 |
Protactinium |
Pa |
|
| 92 |
Uranium |
U |
| +3 |
102. Bismuth (ˈbɪzməθ is a Chemical element that has the symbol Bi and Atomic number 83 Polonium (pəˈloʊniəm is a Chemical element with the symbol Po and Atomic number 84 discovered in 1898 by Marie and Pierre Curie Astatine (ˈæstətiːn is a Radioactive Chemical element with the symbol At and Atomic number 85 Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and Radium (ˈreɪdiəm is a radioactive Chemical element which has the symbol Ra and Atomic number 88 Actinium (ækˈtɪniəm is a radioactive Chemical element with the symbol Ac and Atomic number 89 which was discovered in 1899, the earliest Thorium (ˈθɔːriəm is a Chemical element with the symbol Th and Atomic number 90 Protactinium (ˌproʊtækˈtɪniəm is a Chemical element with the symbol Pa and Atomic number 91 Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the 5 |
| +4 |
89 |
| +5 |
78 |
| +6 |
73 |
|
| 93 |
Neptunium |
Np |
| +2 |
110 |
| +3 |
101 |
| +4 |
87 |
| +5 |
75 |
| +6 |
72 |
| +7 |
71 |
|
| 94 |
Plutonium |
Pu |
|
| 95 |
Americium |
Am |
| +28 |
126 |
| +3 |
97. Neptunium (nɛpˈtjuːniəm is a Chemical element with the symbol Np and Atomic number 93 Americium (ˌæməˈrɪsiəm is a Synthetic element that has the symbol Am and Atomic number 95 5 |
| +4 |
85 |
|
| 96 |
Curium |
Cm |
|
| 97 |
Berkelium |
Bk |
|
| 98 |
Californium |
Cf |
| +3 |
95 |
| +4 |
82. This article is about the chemical element Curium for the ancient city also called Curium (located in Cyprus see Kourion Curium (ˈkjuːriəm Bk redirects here For other uses of the abbreviation see BK (disambiguation. Californium (ˌkælɪˈforniəm is a Metallic Chemical element with the symbol Cf and Atomic number 98 1 |
|
See also
References
- ^ Pauling, L. (1960). Chemical elements data references Atomic radii Note All measurements given are in Picometres (pm Linus Carl Pauling (February 28 1901 – August 19 1994 was an American Scientist, Peace activist, Author and educator. The Nature of the Chemical Bond (3rd Edn. ). Ithaca, NY: Cornell University Press. The City of Ithaca (named for the Greek island of Ithaca) sits on the southern shore of Cayuga Lake, in Central New York
- ^ a b Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides Shannon R. D. Acta Cryst. A32 751-767 (1976) doi:10.1107/S0567739476001551
- ^ On the basis of conventional ionic radii, Ag+ (129 pm) is indeed larger than Na+ (116 pm)
External links
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