Elemental classification Lewis acid/base Pearson’s hard/soft metals Ionic and covalent index Ionic potentials

Earth Scientist's Periodic Table of the Elements and Their Ions

Common minerals and aqueous species in soils

Familiar with equilibrium reactions Use log activity-pH graphs

Trace metals reviewTrace metals review

Elemental Distribution in Sedimentary Rocks based on IP

Accumulation of minor elements in SR is linked to IP (z/r) and metal solubility in water

IP<2.5(low IP)

2.5IP<9.5(Intermediate)

IP>9.5(High IP)

Ba, Li, Rb, Sr

(remain in solution)

REEs, Cu, Ni, Pb, U, Zn, Zr, Tl, Sc, Ge, Cr, Co,….(will precipitate)

As, B, Mo, Se

(will form oxyanions)

If H—O > M—O: M remains in solution (poor incorporation in rocks)If H—O < M—O: M appropriates one or more O from water molecules forming oxyanions and releasing H+:

Se+6 + 4H2O SeO42- + 8H+

If H—O Me—O: leads to the formation of an insoluble hydroxide:

Zn2+ + 2H2O Zn(OH)2 + 2H+

JCB lecture 1/13

Classification based on IP Medium IPMedium IP (2.5-9.5)

Strong bond w/ O-enter early in igneous rocks Make oxides-insoluble Concentrated in soils Not nutrients Least depleted from the mantle

LowLow IPIP (<2.5) Weak bond w/ O-enter late in igneous rocks Make fluoride minerals-soluble Abundant in rivers and seawaters Serves as nutrients

AgHg

F HardClBrI Soft

MgNa

Hard metals: are more likely to form oxides, carbonates, nitrides and fluorides (O, N, and F)

Soft metals: are more likely to form phosphides, sulfides and selinides (P, S, Cl, Br and I).

Classification based on IP Medium IPMedium IP (2.5-9.5)

Strong bond w/ O-enter early in igneous rocks Make oxides-insoluble Concentrated in soils Not nutrients Least depleted from the mantle

LowLow IPIP (<2.5) Weak bond w/ O-enter late in igneous rocks Make fluoride minerals-soluble Abundant in rivers and seawaters Serves as nutrients

HighHigh IPIP (>9.5) Strongest bond w/ O-enter really late in igneous rocks Make oxyanions-soluble Abundant in rivers and seawaters Serves as nutrients

http://www.gly.uga.edu/railsback/PTTalk/PTTalk138.html

Fig. 1 Elemental speciation in aqueous solution

Low T/Late crystalizationSoluble nutrients

High T/early crystalizationInsoluble not nutrients

Too late crystalizationSoluble nutrients

2.3. Goldschmidt’s Geochemical Classification

SIDEROPHILE: They occur with native iron: Fe, Co, Ni, Ru, Rh, Pd, Re, Os, Ir, Pt, Au, Mo, Ge, Sn, C, P, (Pb), (As), (W)

CHALCOPHILE: Concentrated in sulfides: Cu, Ag, (Au), Zn, Cd, Hg, Ga, In, Tl, (Ge), (Sn), Pb, As, Sb, Bi, S, Se, Te, (Fe), (Mo), (Re)

LITHOPHILE: Associated with silicatesLi, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, (Pb), B, Al, Sc, Y, REE, (C), Si, Ti, Zr, Hf, Th, (P), V, Nb, Ta, O, Cr, W, U, (Fe), Mn, F, Cl, I, (H), (Tl), (Ga), (Ge), (N)

ATMOPHILE: prevalent in gas phase H, N, (C), (O), (F), (Cl), (Br), (I), He, Ne, Ar, Kr, Xe

Center of the Periodic Table (mostly noble metals)

Right of the Periodic Table

Left of center of the Periodic Table

Extreme right of the Periodic Table

JCB lecture 1/13

JCB lecture

Hard cationsHard cationsIntermediateIntermediate cationscations

Classification based on hard/soft cations

Hard cationsHard cations Lithophile-Si

IntermediateIntermediate cationscations Siderphile-Fe

Soft cationsSoft cations Chalcophile-S

Chemical Equilibria in Soils (Lindsay, 1979)Chemical Equilibria in Soils (Lindsay, 1979)