128:
116:
2023:. Additional one-parameter base strength scales have been presented. However, it has been shown that to define the order of Lewis base strength (or Lewis acid strength) at least two properties must be considered. For Pearson's qualitative HSAB theory the two properties are hardness and strength while for Drago's quantitative
1470:
1796:
2011:
The W term represents a constant energy contribution for acid–base reaction such as the cleavage of a dimeric acid or base. The equation predicts reversal of acids and base strengths. The graphical presentations of the equation show that there is no single order of Lewis base strengths or Lewis acid
2015:
A related method adopting the E and C formalism of Drago and co-workers quantitatively predicts the formation constants for complexes of many metal ions plus the proton with a wide range of unidentate Lewis acids in aqueous solution, and also offered insights into factors governing HSAB behavior in
2107:
Reanalysis of a large number of various most typical ambident organic system reveals that thermodynamic/kinetic control describes reactivity of organic compounds perfectly, whereas the HSAB principle fails and should be abandoned in the rationalization of ambident reactivity of organic compounds.
2098:
2 mechanism is involved and whether hard or soft electrophiles are employed. Preferred N attack, as postulated for hard electrophiles by the HSAB principle, could not be observed with any alkylating agent. Isocyano compounds are only formed with highly reactive electrophiles that react without an
1929:
1239:
2099:
activation barrier because the diffusion limit is approached. It is claimed that the knowledge of absolute rate constants and not of the hardness of the reaction partners is needed to predict the outcome of alkylations of the cyanide ion.
2492:
Strutinsky's shell-correction method in the extended Kohn-Sham scheme: application to the ionization potential, electron affinity, electronegativity and chemical hardness of atoms in Recent
Advances in the Theory of Chemical and Physical
1577:
1220:
64:
The theory is used in contexts where a qualitative, rather than quantitative, description would help in understanding the predominant factors which drive chemical properties and reactions. This is especially so in
1565:
156:
bases, all other factors being equal. It can also be said that hard acids bind strongly to hard bases and soft acids bind strongly to soft bases. The HASB classification in the original work was largely based on
1832:
1970:
is quantitative model that describes and predicts the strength of Lewis acid base interactions, -ΔH . The model assigned E and C parameters to many Lewis acids and bases. Each acid is characterized by an
1582:
1244:
2629:
Cramer, R. E., and Bopp, T. T. (1977) Great E and C plot. Graphical display of the enthalpies of adduct formation for Lewis acids and bases. Journal of
Chemical Education 54 612-613
2579:
Christe, K.O.; Dixon, D.A.; McLemore, D.; Wilson, W.W.; Sheehy, J.A.; Boatz, J.A. (2000). "On a quantitative scale for Lewis acidity and recent progress in polynitrogen chemistry".
2639:
The
Mechanism of the Reaction of Silver Nitrite with Alkyl Halides. The Contrasting Reactions of Silver and Alkali Metal Salts with Alkyl Halides. The Alkylation of Ambident Anions
2167:
E.-C. Koch, Acid-Base
Interactions in Energetic Materials: I. The Hard and Soft Acids and Bases (HSAB) Principle-Insights to Reactivity and Sensitivity of Energetic Materials,
1987:. The E and C parameters refer, respectively, to the electrostatic and covalent contributions to the strength of the bonds that the acid and base will form. The equation is
1137:) as being proportional to the second derivative of the total energy of a chemical system with respect to changes in the number of electrons at a fixed nuclear environment:
1465:{\displaystyle {\begin{aligned}\eta &\approx {\frac {E(N+1)-2E(N)+E(N-1)}{2}}\\&={\frac {(E(N-1)-E(N))-(E(N)-E(N+1))}{2}}\\&={\frac {1}{2}}(I-A)\end{aligned}}}
1791:{\displaystyle {\begin{aligned}\mu &\approx {\frac {E(N+1)-E(N-1)}{2}}\\&={\frac {-(E(N-1)-E(N))-(E(N)-E(N+1))}{2}}\\&=-{\frac {1}{2}}(I+A)\end{aligned}}}
1143:
57:. 'Hard' applies to species which are small, have high charge states (the charge criterion applies mainly to acids, to a lesser extent to bases), and are weakly
1958:
If the interaction between acid and base in solution results in an equilibrium mixture the strength of the interaction can be quantified in terms of an
1571:
from which an operational definition for the chemical potential is obtained from a finite difference approximation to the first order derivative as
2165:
17:
2283:
1512:
83:
reactions. In 2005 it was shown that even the sensitivity and performance of explosive materials can be explained on basis of HSAB theory.
2019:
Another quantitative system has been proposed, in which Lewis acid strength toward Lewis base fluoride is based on gas-phase affinity for
1924:{\displaystyle 2\eta =\left({\frac {\partial \mu }{\partial N}}\right)_{Z}\approx -\left({\frac {\partial \chi }{\partial N}}\right)_{Z}}
2489:
Delchev, Ya. I.; A. I. Kuleff; J. Maruani; Tz. Mineva; F. Zahariev (2006). Jean-Pierre Julien; Jean
Maruani; Didier Mayou (eds.).
2618:
2501:
2150:
1935:
and in this sense hardness is a measure for resistance to deformation or change. Likewise a value of zero denotes maximum
2552:
Hancock, R. D.; Martell, A. E. (1989). "Ligand design for the selective complexation of metal ions in aqueous solution".
2666:
Tishkov, Alexander A.; Mayr, Herbert (2004). "Ambident
Reactivity of the Cyanide Ion: A Failure of the HSAB Principle".
2409:
Robert G. Parr & Ralph G. Pearson (1983). "Absolute hardness: companion parameter to absolute electronegativity".
2741:
2071:
reaction. This rule (established in 1954) predates HSAB theory but in HSAB terms its explanation is that in a S
2012:
strengths. The ECW model accommodates the failure of single parameter descriptions of acid-base interactions.
2746:
2285:
R. G. Pearson, Chemical
Hardness – Applications From Molecules to Solids, Wiley-VCH, Weinheim, 1997, 198 pp
1946:
anion deviates. Another discrepancy noted in the original 1983 article are the apparent higher hardness of
1812:
765:
ion) is a very soft acid and H (proton) is a hard acid, which compete for B (the base to be classified).
2613:
Laurence, C. and Gal, J-F. Lewis
Basicity and Affinity Scales, Data and Measurement, (Wiley 2010) p 51
2458:
80:
2212:
Pearson, Ralph G. (1968). "Hard and soft acids and bases, HSAB, part 1: Fundamental principles".
2087:
61:. 'Soft' applies to species which are big, have low charge states and are strongly polarizable.
2453:
2248:
Pearson, Ralph G. (1968). "Hard and soft acids and bases, HSAB, part II: Underlying theories".
823:
1215:{\displaystyle \eta ={\frac {1}{2}}\left({\frac {\partial ^{2}E}{\partial N^{2}}}\right)_{Z}}
726:
Generally speaking, acids and bases interact and the most stable interactions are hard–hard (
38:
2526:
2258:
2222:
2044:
1959:
1498:
The first derivative of the energy with respect to the number of electrons is equal to the
1480:
738:
158:
1229:
An operational definition for the chemical hardness is obtained by applying a three-point
8:
90:
2530:
2262:
2226:
2471:
2117:
2052:
1499:
812:
773:
50:
2592:
2381:
2718:
2683:
2642:
2614:
2596:
2497:
2411:
2396:
Miessler G.L. and Tarr D.A. "Inorganic
Chemistry" 2nd ed. Prentice-Hall 1999, p.181-5
2357:
2318:
2186:
2146:
1802:
1488:
1230:
784:
479:
332:
227:
94:
46:
2475:
2710:
2675:
2650:
2588:
2561:
2534:
2463:
2438:
2419:
2349:
2337:
2308:
2297:"Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)"
2266:
2230:
2194:
66:
54:
72:, where numerous experiments have been done to determine the relative ordering of
2490:
2048:
2040:
940:
808:
660:
565:
201:
1966:) of formation of the Lewis acid-base adduct in a non-coordinating solvent. The
2701:
Mayr, Herbert (2011). "Farewell to the HSAB Treatment of
Ambident Reactivity".
2250:
2214:
1058:
1028:
792:
664:
214:
58:
2079:(a hard acid) reacts with a hard base (high electronegativity) and that in a S
819:
are soft solvents with a preference for solvating large anions and soft bases.
2735:
2600:
2361:
2322:
837:
826:
soft–soft and hard–hard interactions exist between ligands and metal centers.
762:
731:
371:
345:
337:
284:
279:
86:
53:
and pathways. It assigns the terms 'hard' or 'soft', and 'acid' or 'base' to
2313:
2296:
1491:. This expression implies that the chemical hardness is proportional to the
1226:
The factor of one-half is arbitrary and often dropped as Pearson has noted.
737:
An attempt to quantify the 'softness' of a base consists in determining the
2722:
2714:
2687:
2679:
2122:
2064:
2056:
1806:
1134:
1129:
extended the qualitative HSAB theory with a quantitative definition of the
1072:
188:
2578:
2076:
1126:
575:
535:
523:
513:
501:
2654:
2565:
2423:
2353:
2198:
89:
introduced the HSAB principle in the early 1960s as an attempt to unify
2641:
Nathan Kornblum, Robert A. Smiley, Robert K. Blackwood, Don C. Iffland
2488:
2467:
727:
2538:
2270:
2234:
1560:{\displaystyle \mu =\left({\frac {\partial E}{\partial N}}\right)_{Z}}
2024:
1967:
1012:
977:
878:
796:
592:
554:
466:
413:
353:
320:
166:
Comparing tendencies of hard acids and bases vs. soft acids and bases
69:
42:
2083:
2 reaction tetravalent carbon (a soft acid) reacts with soft bases.
2020:
1963:
1947:
1492:
964:
929:
865:
860:
852:
800:
708:
696:
692:
439:
429:
421:
405:
395:
387:
379:
161:
of Lewis acid/base reactions with a reference base for comparison.
76:
and transition metal ions in terms of their hardness and softness.
2047:(nucleophiles that can attack from two or more places), the more
1943:
1099:
1042:
988:
916:
905:
889:
816:
780:
720:
716:
712:
688:
676:
668:
628:
624:
607:
455:
361:
34:
127:
115:
1085:
953:
672:
584:
490:
447:
73:
2408:
2377:
804:
788:
704:
768:
Some examples illustrating the effectiveness of the theory:
257:
2184:
Pearson, Ralph G. (1963). "Hard and Soft Acids and Bases".
2090:
occur preferentially at carbon, regardless of whether the S
1939:, where softness is defined as the reciprocal of hardness.
1826:
The hardness and Mulliken electronegativity are related as
1001:
680:
636:
258:
242:
241:
79:
HSAB theory is also useful in predicting the products of
2516:
2382:
Glossary of terms used in theoretical organic chemistry
2551:
1942:
In a compilation of hardness values only that of the
1835:
1580:
1515:
1242:
1146:
2027:
the two properties are electrostatic and covalent .
2517:Vogel G. C.; Drago, R. S. (1996). "The ECW Model".
1962:. An alternative quantitative measure is the heat (
1979:. Each base is likewise characterized by its own E
1923:
1790:
1559:
1464:
1214:
2439:"Chemical hardness and density functional theory"
2247:
2211:
2183:
2733:
2436:
2496:. New York: Springer-Verlag. pp. 159–177.
2035:An application of HSAB theory is the so-called
776:by soft bases such as phosphines and sulfides.
2404:
2402:
2140:
2665:
2392:
2390:
2399:
293:Examples of hard and soft acids and bases
2457:
2312:
1495:of a chemical system, when a gap exists.
2387:
2342:Journal of the American Chemical Society
1233:approximation to the second derivative:
846:
843:
314:
311:
308:
305:
300:
297:
2703:Angewandte Chemie International Edition
2668:Angewandte Chemie International Edition
2373:
2371:
2335:
14:
2734:
2294:
2063:and the less electronegative one in a
2043:) which states that in reactions with
1801:which is equal to the negative of the
1114:
655:Borderline cases are also identified:
27:Chemical theory about acids and bases
2700:
2368:
2088:electrophilic alkylations at free CN
830:
140:Essentially, the theory states that
108:Hard–soft trends for acids and bases
807:anions. On the other hand, dipolar
772:Bulk metals are soft acids and are
24:
2030:
1902:
1894:
1861:
1853:
1538:
1530:
1186:
1172:
25:
2758:
835:
1953:
152:acids prefer to form bonds with
144:acids prefer to form bonds with
126:
114:
45:for explaining the stability of
2694:
2659:
2632:
2623:
2607:
2572:
2545:
2510:
2482:
2430:
2338:"Hard and Soft Acids and Bases"
1117:Table 2. Chemical hardness data
741:for the following equilibrium:
291:
2329:
2288:
2277:
2241:
2205:
2177:
2159:
2134:
1781:
1769:
1737:
1734:
1722:
1713:
1707:
1701:
1695:
1692:
1686:
1677:
1665:
1659:
1634:
1622:
1613:
1601:
1455:
1443:
1414:
1411:
1399:
1390:
1384:
1378:
1372:
1369:
1363:
1354:
1342:
1336:
1314:
1302:
1293:
1287:
1275:
1263:
1125:In 1983 Pearson together with
834:
270:(but more than soft-base HOMO)
13:
1:
2593:10.1016/S0022-1139(99)00151-7
2581:Journal of Fluorine Chemistry
2519:Journal of Chemical Education
2128:
18:Hard and soft acids and bases
2102:
799:strong solute bases such as
7:
2111:
41:". HSAB is widely used in
10:
2763:
2336:Pearson, Ralph G. (1963).
2301:Pure and Applied Chemistry
2143:Modern Inorganic Chemistry
730:character) and soft–soft (
2437:Ralph G. Pearson (2005).
2295:Muller, P. (1994-01-01).
2145:. New York: McGraw-Hill.
100:
2169:Prop.,Expl.,Pyrotech. 30
2384:, accessed 16 Dec 2006.
2314:10.1351/pac199466051077
2086:According to findings,
39:(Lewis) acids and bases
2715:10.1002/anie.201007100
2680:10.1002/anie.200461640
1925:
1792:
1561:
1466:
1216:
824:coordination chemistry
2649:; 77(23); 6269-6280.
2141:Jolly, W. L. (1984).
2051:atom reacts when the
2045:ambident nucleophiles
1926:
1793:
1562:
1467:
1217:
836:Chemical hardness in
159:equilibrium constants
1960:equilibrium constant
1833:
1811:) definition on the
1578:
1513:
1481:ionization potential
1240:
1144:
739:equilibrium constant
181:Soft acids and bases
176:Hard acids and bases
97:reaction chemistry.
2747:Inorganic chemistry
2742:Acid–base chemistry
2655:10.1021/ja01628a064
2566:10.1021/cr00098a011
2531:1996JChEd..73..701V
2424:10.1021/ja00364a005
2354:10.1021/ja00905a001
2263:1968JChEd..45..643P
2227:1968JChEd..45..581P
2199:10.1021/ja00905a001
840:
294:
168:
51:reaction mechanisms
37:for "hard and soft
2468:10.1007/BF02708340
2118:Acid-base reaction
2053:reaction mechanism
1921:
1788:
1786:
1557:
1500:chemical potential
1462:
1460:
1212:
813:dimethyl sulfoxide
292:
164:
2709:(29): 6470–6505.
2643:J. Am. Chem. Soc.
2619:978-0-470-74957-9
2539:10.1021/ed073p701
2503:978-1-4020-4527-1
2418:(26): 7512–7516.
2412:J. Am. Chem. Soc.
2348:(22): 3533–3539.
2271:10.1021/ed045p643
2235:10.1021/ed045p581
2193:(22): 3533–3539.
2187:J. Am. Chem. Soc.
2152:978-0-07-032760-3
1909:
1868:
1803:electronegativity
1767:
1744:
1641:
1545:
1506:, of the system,
1489:electron affinity
1441:
1421:
1321:
1231:finite difference
1200:
1161:
1131:chemical hardness
1123:
1122:
831:Chemical hardness
785:hydrogen fluoride
653:
652:
480:Boron trifluoride
290:
289:
228:electronegativity
16:(Redirected from
2754:
2727:
2726:
2698:
2692:
2691:
2663:
2657:
2636:
2630:
2627:
2621:
2611:
2605:
2604:
2576:
2570:
2569:
2560:(8): 1875–1914.
2554:Chemical Reviews
2549:
2543:
2542:
2514:
2508:
2507:
2486:
2480:
2479:
2461:
2443:
2434:
2428:
2427:
2406:
2397:
2394:
2385:
2375:
2366:
2365:
2333:
2327:
2326:
2316:
2307:(5): 1077–1184.
2292:
2286:
2281:
2275:
2274:
2245:
2239:
2238:
2209:
2203:
2202:
2181:
2175:
2163:
2157:
2156:
2138:
1950:compared to Tl.
1930:
1928:
1927:
1922:
1920:
1919:
1914:
1910:
1908:
1900:
1892:
1879:
1878:
1873:
1869:
1867:
1859:
1851:
1797:
1795:
1794:
1789:
1787:
1768:
1760:
1749:
1745:
1740:
1654:
1646:
1642:
1637:
1596:
1566:
1564:
1563:
1558:
1556:
1555:
1550:
1546:
1544:
1536:
1528:
1471:
1469:
1468:
1463:
1461:
1442:
1434:
1426:
1422:
1417:
1334:
1326:
1322:
1317:
1258:
1221:
1219:
1218:
1213:
1211:
1210:
1205:
1201:
1199:
1198:
1197:
1184:
1180:
1179:
1169:
1162:
1154:
841:
809:aprotic solvents
685:Borderline bases
657:borderline acids
295:
285:covalent bonding
271:
261:
245:
182:
177:
169:
167:
163:
130:
118:
67:transition metal
55:chemical species
21:
2762:
2761:
2757:
2756:
2755:
2753:
2752:
2751:
2732:
2731:
2730:
2699:
2695:
2664:
2660:
2637:
2633:
2628:
2624:
2612:
2608:
2577:
2573:
2550:
2546:
2515:
2511:
2504:
2487:
2483:
2459:10.1.1.693.7436
2441:
2435:
2431:
2407:
2400:
2395:
2388:
2376:
2369:
2334:
2330:
2293:
2289:
2282:
2278:
2257:(45): 643–648.
2246:
2242:
2221:(45): 581–586.
2210:
2206:
2182:
2178:
2164:
2160:
2153:
2139:
2135:
2131:
2114:
2105:
2097:
2093:
2082:
2075:1 reaction the
2074:
2068:
2060:
2049:electronegative
2041:Nathan Kornblum
2037:Kornblum's rule
2033:
2031:Kornblum's rule
2006:
2002:
1998:
1994:
1986:
1982:
1978:
1974:
1956:
1915:
1901:
1893:
1891:
1887:
1886:
1874:
1860:
1852:
1850:
1846:
1845:
1834:
1831:
1830:
1785:
1784:
1759:
1747:
1746:
1655:
1653:
1644:
1643:
1597:
1595:
1588:
1581:
1579:
1576:
1575:
1551:
1537:
1529:
1527:
1523:
1522:
1514:
1511:
1510:
1459:
1458:
1433:
1424:
1423:
1335:
1333:
1324:
1323:
1259:
1257:
1250:
1243:
1241:
1238:
1237:
1206:
1193:
1189:
1185:
1175:
1171:
1170:
1168:
1164:
1163:
1153:
1145:
1142:
1141:
1119:
1107:
1093:
1066:
1050:
1036:
1020:
941:carbon monoxide
897:
833:
793:protic solvents
760:
752:
748:
702:
661:trimethylborane
619:
615:
604:
600:
566:Carbon monoxide
562:
551:
547:
543:
531:
509:
498:
487:
474:
463:
349:
341:
328:
269:
262:energy of acids
246:energy of bases
202:oxidation state
180:
175:
165:
148:bases, whereas
138:
137:
136:
135:
134:
131:
123:
122:
119:
110:
109:
103:
28:
23:
22:
15:
12:
11:
5:
2760:
2750:
2749:
2744:
2729:
2728:
2693:
2674:(1): 142–145.
2658:
2631:
2622:
2606:
2587:(2): 151–153.
2571:
2544:
2525:(8): 701–707.
2509:
2502:
2481:
2452:(5): 369–377.
2429:
2398:
2386:
2367:
2328:
2287:
2276:
2251:J. Chem. Educ.
2240:
2215:J. Chem. Educ.
2204:
2176:
2158:
2151:
2132:
2130:
2127:
2126:
2125:
2120:
2113:
2110:
2104:
2101:
2095:
2091:
2080:
2072:
2066:
2058:
2032:
2029:
2009:
2008:
2004:
2000:
1996:
1992:
1984:
1980:
1976:
1972:
1955:
1952:
1933:
1932:
1918:
1913:
1907:
1904:
1899:
1896:
1890:
1885:
1882:
1877:
1872:
1866:
1863:
1858:
1855:
1849:
1844:
1841:
1838:
1813:Mulliken scale
1799:
1798:
1783:
1780:
1777:
1774:
1771:
1766:
1763:
1758:
1755:
1752:
1750:
1748:
1743:
1739:
1736:
1733:
1730:
1727:
1724:
1721:
1718:
1715:
1712:
1709:
1706:
1703:
1700:
1697:
1694:
1691:
1688:
1685:
1682:
1679:
1676:
1673:
1670:
1667:
1664:
1661:
1658:
1652:
1649:
1647:
1645:
1640:
1636:
1633:
1630:
1627:
1624:
1621:
1618:
1615:
1612:
1609:
1606:
1603:
1600:
1594:
1591:
1589:
1587:
1584:
1583:
1569:
1568:
1554:
1549:
1543:
1540:
1535:
1532:
1526:
1521:
1518:
1473:
1472:
1457:
1454:
1451:
1448:
1445:
1440:
1437:
1432:
1429:
1427:
1425:
1420:
1416:
1413:
1410:
1407:
1404:
1401:
1398:
1395:
1392:
1389:
1386:
1383:
1380:
1377:
1374:
1371:
1368:
1365:
1362:
1359:
1356:
1353:
1350:
1347:
1344:
1341:
1338:
1332:
1329:
1327:
1325:
1320:
1316:
1313:
1310:
1307:
1304:
1301:
1298:
1295:
1292:
1289:
1286:
1283:
1280:
1277:
1274:
1271:
1268:
1265:
1262:
1256:
1253:
1251:
1249:
1246:
1245:
1224:
1223:
1209:
1204:
1196:
1192:
1188:
1183:
1178:
1174:
1167:
1160:
1157:
1152:
1149:
1121:
1120:
1115:
1112:
1111:
1108:
1105:
1102:
1097:
1094:
1091:
1088:
1082:
1081:
1078:
1075:
1070:
1067:
1064:
1061:
1059:Sulfur dioxide
1055:
1054:
1051:
1048:
1045:
1040:
1037:
1034:
1031:
1029:Carbon dioxide
1025:
1024:
1021:
1018:
1015:
1010:
1007:
1004:
998:
997:
994:
991:
986:
983:
980:
974:
973:
970:
967:
962:
959:
956:
950:
949:
946:
943:
938:
935:
932:
926:
925:
922:
919:
914:
911:
908:
902:
901:
898:
895:
892:
887:
884:
881:
875:
874:
871:
868:
863:
858:
855:
849:
848:
845:
832:
829:
828:
827:
820:
777:
758:
755:
754:
750:
746:
700:
665:sulfur dioxide
651:
650:
648:
646:
644:
642:
639:
634:
631:
621:
620:
617:
613:
610:
605:
602:
598:
595:
590:
587:
581:
578:
572:
571:
568:
563:
560:
557:
552:
549:
545:
541:
538:
533:
529:
526:
520:
519:
516:
511:
507:
504:
499:
496:
493:
488:
485:
482:
476:
475:
472:
469:
464:
461:
458:
453:
450:
445:
442:
436:
435:
432:
427:
424:
419:
416:
411:
408:
402:
401:
398:
393:
390:
385:
382:
377:
374:
368:
367:
364:
359:
356:
351:
347:
339:
335:
330:
326:
323:
317:
316:
313:
310:
307:
303:
302:
299:
288:
287:
282:
277:
273:
272:
266:
263:
254:
253:
250:
247:
238:
237:
234:
231:
224:
223:
220:
217:
215:polarizability
211:
210:
207:
204:
198:
197:
194:
191:
184:
183:
178:
173:
132:
125:
124:
120:
113:
112:
111:
107:
106:
105:
104:
102:
99:
26:
9:
6:
4:
3:
2:
2759:
2748:
2745:
2743:
2740:
2739:
2737:
2724:
2720:
2716:
2712:
2708:
2704:
2697:
2689:
2685:
2681:
2677:
2673:
2669:
2662:
2656:
2652:
2648:
2644:
2640:
2635:
2626:
2620:
2616:
2610:
2602:
2598:
2594:
2590:
2586:
2582:
2575:
2567:
2563:
2559:
2555:
2548:
2540:
2536:
2532:
2528:
2524:
2520:
2513:
2505:
2499:
2495:
2494:
2485:
2477:
2473:
2469:
2465:
2460:
2455:
2451:
2447:
2440:
2433:
2425:
2421:
2417:
2414:
2413:
2405:
2403:
2393:
2391:
2383:
2379:
2374:
2372:
2363:
2359:
2355:
2351:
2347:
2343:
2339:
2332:
2324:
2320:
2315:
2310:
2306:
2302:
2298:
2291:
2284:
2280:
2272:
2268:
2264:
2260:
2256:
2253:
2252:
2244:
2236:
2232:
2228:
2224:
2220:
2217:
2216:
2208:
2200:
2196:
2192:
2189:
2188:
2180:
2173:
2170:
2166:
2162:
2154:
2148:
2144:
2137:
2133:
2124:
2121:
2119:
2116:
2115:
2109:
2100:
2089:
2084:
2078:
2070:
2062:
2054:
2050:
2046:
2042:
2038:
2028:
2026:
2022:
2017:
2013:
1990:
1989:
1988:
1969:
1965:
1961:
1954:Modifications
1951:
1949:
1945:
1940:
1938:
1916:
1911:
1905:
1897:
1888:
1883:
1880:
1875:
1870:
1864:
1856:
1847:
1842:
1839:
1836:
1829:
1828:
1827:
1824:
1822:
1818:
1814:
1810:
1809:
1804:
1778:
1775:
1772:
1764:
1761:
1756:
1753:
1751:
1741:
1731:
1728:
1725:
1719:
1716:
1710:
1704:
1698:
1689:
1683:
1680:
1674:
1671:
1668:
1662:
1656:
1650:
1648:
1638:
1631:
1628:
1625:
1619:
1616:
1610:
1607:
1604:
1598:
1592:
1590:
1585:
1574:
1573:
1572:
1552:
1547:
1541:
1533:
1524:
1519:
1516:
1509:
1508:
1507:
1505:
1501:
1496:
1494:
1490:
1486:
1482:
1478:
1452:
1449:
1446:
1438:
1435:
1430:
1428:
1418:
1408:
1405:
1402:
1396:
1393:
1387:
1381:
1375:
1366:
1360:
1357:
1351:
1348:
1345:
1339:
1330:
1328:
1318:
1311:
1308:
1305:
1299:
1296:
1290:
1284:
1281:
1278:
1272:
1269:
1266:
1260:
1254:
1252:
1247:
1236:
1235:
1234:
1232:
1227:
1207:
1202:
1194:
1190:
1181:
1176:
1165:
1158:
1155:
1150:
1147:
1140:
1139:
1138:
1136:
1132:
1128:
1118:
1113:
1109:
1103:
1101:
1098:
1095:
1089:
1087:
1084:
1083:
1079:
1076:
1074:
1071:
1068:
1062:
1060:
1057:
1056:
1052:
1046:
1044:
1041:
1038:
1032:
1030:
1027:
1026:
1022:
1016:
1014:
1011:
1008:
1005:
1003:
1000:
999:
995:
992:
990:
987:
984:
981:
979:
976:
975:
971:
968:
966:
963:
960:
957:
955:
952:
951:
947:
944:
942:
939:
936:
933:
931:
928:
927:
923:
920:
918:
915:
912:
909:
907:
904:
903:
899:
893:
891:
888:
885:
882:
880:
877:
876:
872:
869:
867:
864:
862:
859:
856:
854:
851:
850:
842:
839:
838:electron volt
825:
821:
818:
814:
810:
806:
802:
798:
794:
790:
786:
782:
778:
775:
771:
770:
769:
766:
764:
763:methylmercury
744:
743:
742:
740:
735:
733:
729:
724:
722:
718:
714:
710:
706:
698:
694:
690:
686:
682:
678:
674:
670:
666:
662:
658:
649:
647:
645:
643:
640:
638:
635:
632:
630:
626:
623:
622:
611:
609:
606:
596:
594:
591:
588:
586:
582:
579:
577:
574:
573:
569:
567:
564:
558:
556:
553:
539:
537:
534:
527:
525:
522:
521:
517:
515:
512:
505:
503:
500:
494:
492:
489:
483:
481:
478:
477:
470:
468:
465:
459:
457:
454:
451:
449:
446:
443:
441:
438:
437:
433:
431:
428:
425:
423:
420:
417:
415:
412:
409:
407:
404:
403:
399:
397:
394:
391:
389:
386:
383:
381:
378:
375:
373:
372:Alkali metals
370:
369:
365:
363:
360:
357:
355:
352:
350:
343:
336:
334:
331:
324:
322:
319:
318:
304:
296:
286:
283:
281:
280:ionic bonding
278:
275:
274:
267:
264:
260:
256:
255:
251:
248:
244:
240:
239:
235:
232:
229:
226:
225:
221:
218:
216:
213:
212:
208:
205:
203:
200:
199:
195:
192:
190:
186:
185:
179:
174:
171:
170:
162:
160:
155:
151:
147:
143:
129:
117:
98:
96:
92:
88:
87:Ralph Pearson
84:
82:
77:
75:
71:
68:
62:
60:
56:
52:
48:
44:
40:
36:
32:
19:
2706:
2702:
2696:
2671:
2667:
2661:
2646:
2638:
2634:
2625:
2609:
2584:
2580:
2574:
2557:
2553:
2547:
2522:
2518:
2512:
2491:
2484:
2449:
2446:J. Chem. Sci
2445:
2432:
2415:
2410:
2345:
2341:
2331:
2304:
2300:
2290:
2279:
2254:
2249:
2243:
2218:
2213:
2207:
2190:
2185:
2179:
2171:
2168:
2161:
2142:
2136:
2123:Oxophilicity
2106:
2085:
2036:
2034:
2018:
2014:
2010:
1957:
1941:
1936:
1934:
1825:
1820:
1816:
1807:
1800:
1570:
1503:
1497:
1484:
1476:
1474:
1228:
1225:
1130:
1124:
1116:
1073:Hydrosulfide
767:
756:
736:
734:character).
725:
684:
683:Pb cations.
656:
654:
209:low or zero
189:ionic radius
153:
149:
145:
141:
139:
85:
78:
63:
30:
29:
2077:carbocation
1127:Robert Parr
749:Hg ⇌ H + CH
576:Lanthanides
536:P-chloranil
524:Carbocation
514:Thiocyanate
502:Carboxylate
59:polarizable
2736:Categories
2129:References
2016:solution.
81:metathesis
2601:0022-1139
2454:CiteSeerX
2362:0002-7863
2323:1365-3075
2103:Criticism
2025:ECW model
1991:-ΔH = E
1968:ECW model
1903:∂
1898:χ
1895:∂
1884:−
1881:≈
1862:∂
1857:μ
1854:∂
1840:η
1757:−
1717:−
1699:−
1681:−
1672:−
1657:−
1629:−
1617:−
1593:≈
1586:μ
1539:∂
1531:∂
1517:μ
1450:−
1394:−
1376:−
1358:−
1349:−
1309:−
1279:−
1255:≈
1248:η
1187:∂
1173:∂
1148:η
1013:phosphine
978:Lanthanum
879:Aluminium
728:ionogenic
593:Hydrazine
555:Carbonate
467:Phosphine
414:Palladium
354:Hydroxide
321:Hydronium
276:affinity
91:inorganic
70:chemistry
47:compounds
43:chemistry
2723:21726020
2688:15599920
2476:96042488
2112:See also
2021:fluoride
1964:enthalpy
1937:softness
1493:band gap
965:hydroxyl
930:Scandium
866:Fluoride
853:Hydrogen
811:such as
801:fluoride
797:dissolve
795:tend to
791:and the
783:such as
781:solvents
774:poisoned
757:Where CH
732:covalent
723:anions.
709:chloride
703:and the
697:nitrogen
693:pyridine
440:Chromium
430:Halogens
422:Halogens
406:Titanium
396:Thiolate
388:Alkoxide
380:Platinum
172:Property
2527:Bibcode
2493:Systems
2259:Bibcode
2223:Bibcode
2039:(after
1975:and a C
1944:hydride
1479:is the
1100:Methane
1043:nitrite
989:cyanide
917:hydride
906:Lithium
890:Ammonia
817:acetone
745:BH + CH
721:sulfate
717:nitrate
713:bromide
689:aniline
679:Cs and
677:caesium
669:ferrous
629:uranium
625:Thorium
608:Benzene
456:Ammonia
376:Li,Na,K
362:Hydride
333:Mercury
252:higher
230:(bases)
187:atomic/
95:organic
74:ligands
35:acronym
2721:
2686:
2617:
2599:
2500:
2474:
2456:
2360:
2321:
2149:
2094:1 or S
1475:where
1086:Iodine
954:Sodium
847:Bases
673:cobalt
585:metals
491:Borane
448:Silver
344:, Hg,
301:Bases
268:lower
196:large
101:Theory
33:is an
2472:S2CID
2442:(PDF)
2378:IUPAC
1983:and C
1483:and
844:Acids
805:oxide
789:water
779:Hard
705:azide
687:are:
633:Th, U
583:Bulk
444:Cr,Cr
315:soft
298:Acids
222:high
193:small
133:Bases
121:Acids
2719:PMID
2684:PMID
2647:1955
2615:ISBN
2597:ISSN
2498:ISBN
2358:ISSN
2319:ISSN
2255:1968
2219:1968
2172:2005
2147:ISBN
2007:+ W
1999:+ C
1487:the
1110:4.0
1080:4.1
1053:4.5
1039:10.8
1023:5.0
1009:10.8
1002:Zinc
996:5.3
985:15.4
972:5.6
961:21.1
948:6.0
937:24.6
924:6.8
913:35.1
900:6.8
886:45.8
815:and
803:and
761:Hg (
719:and
681:lead
671:Fe,
667:and
659:are
637:Gold
518:SCN
426:F,Cl
312:hard
309:soft
306:hard
265:high
259:LUMO
243:HOMO
236:low
233:high
206:high
154:hard
150:hard
146:soft
142:soft
93:and
31:HSAB
2711:doi
2676:doi
2651:doi
2589:doi
2585:101
2562:doi
2535:doi
2464:doi
2450:117
2420:doi
2416:105
2350:doi
2309:doi
2267:doi
2231:doi
2195:doi
2174:, 5
2055:is
1819:= −
1096:3.4
1069:5.6
822:In
753:HgB
675:Co
570:CO
510:COO
400:RS
249:low
219:low
2738::
2717:.
2707:50
2705:.
2682:.
2672:44
2670:.
2645:;
2595:.
2583:.
2558:89
2556:.
2533:.
2523:73
2521:.
2470:.
2462:.
2448:.
2444:.
2401:^
2389:^
2380:,
2370:^
2356:.
2346:85
2344:.
2340:.
2317:.
2305:66
2303:.
2299:.
2265:.
2229:.
2191:85
1948:Tl
1823:.
1815::
1502:,
1104:CH
1077:SH
1063:SO
1047:NO
1033:CO
1017:PH
1006:Zn
993:CN
982:La
969:OH
958:Na
945:CO
934:Sc
910:Li
894:NH
883:Al
873:7
787:,
715:,
711:,
707:,
695:,
691:,
663:,
641:Au
627:,
580:Ln
559:CO
544:Cl
506:CH
495:BH
484:BF
471:PR
460:NH
452:Ag
434:I
418:Pd
410:Ti
392:RO
384:Pt
366:H
358:OH
346:Hg
342:Hg
338:CH
49:,
2725:.
2713::
2690:.
2678::
2653::
2603:.
2591::
2568:.
2564::
2541:.
2537::
2529::
2506:.
2478:.
2466::
2426:.
2422::
2364:.
2352::
2325:.
2311::
2273:.
2269::
2261::
2237:.
2233::
2225::
2201:.
2197::
2155:.
2096:N
2092:N
2081:N
2073:N
2069:2
2067:N
2065:S
2061:1
2059:N
2057:S
2005:B
2003:C
2001:A
1997:B
1995:E
1993:A
1985:B
1981:B
1977:A
1973:A
1971:E
1931:,
1917:Z
1912:)
1906:N
1889:(
1876:Z
1871:)
1865:N
1848:(
1843:=
1837:2
1821:χ
1817:μ
1808:χ
1805:(
1782:)
1779:A
1776:+
1773:I
1770:(
1765:2
1762:1
1754:=
1742:2
1738:)
1735:)
1732:1
1729:+
1726:N
1723:(
1720:E
1714:)
1711:N
1708:(
1705:E
1702:(
1696:)
1693:)
1690:N
1687:(
1684:E
1678:)
1675:1
1669:N
1666:(
1663:E
1660:(
1651:=
1639:2
1635:)
1632:1
1626:N
1623:(
1620:E
1614:)
1611:1
1608:+
1605:N
1602:(
1599:E
1567:,
1553:Z
1548:)
1542:N
1534:E
1525:(
1520:=
1504:μ
1485:A
1477:I
1456:)
1453:A
1447:I
1444:(
1439:2
1436:1
1431:=
1419:2
1415:)
1412:)
1409:1
1406:+
1403:N
1400:(
1397:E
1391:)
1388:N
1385:(
1382:E
1379:(
1373:)
1370:)
1367:N
1364:(
1361:E
1355:)
1352:1
1346:N
1343:(
1340:E
1337:(
1331:=
1319:2
1315:)
1312:1
1306:N
1303:(
1300:E
1297:+
1294:)
1291:N
1288:(
1285:E
1282:2
1276:)
1273:1
1270:+
1267:N
1264:(
1261:E
1222:.
1208:Z
1203:)
1195:2
1191:N
1182:E
1177:2
1166:(
1159:2
1156:1
1151:=
1135:η
1133:(
1106:3
1092:2
1090:I
1065:2
1049:2
1035:2
1019:3
921:H
896:3
870:F
861:∞
857:H
759:3
751:3
747:3
701:2
699:N
618:6
616:H
614:6
612:C
603:4
601:H
599:2
597:N
589:M
561:3
550:2
548:O
546:4
542:6
540:C
532:C
530:3
528:R
508:3
497:3
486:3
473:3
462:3
348:2
340:3
329:O
327:3
325:H
20:)
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