Technical articles

Post-Transition Metals and Their Salts: A Classification Guide from Definitions to Value-Chain Applications (Including Product Lists in Tables 1–4)

What are post-transition metals?

Post-transition metals usually refer to a set of main-group metals (mostly in the p-block) that sit to the right of the transition metals in the periodic table, close to the boundary between metals and metalloids/nonmetals. They are also often labeled poor metals / p-block metals / other metals, depending on the source and context. This is a teaching/engineering convenience label, not an element family strictly defined by IUPAC. Its key purpose is to conveniently describe metals whose properties lie between typical metals and metalloids, and whose chemistry behaves more like main-group elements.

Why is the boundary not unique?

Like the category “metalloid,” post-transition metals do not have a globally unified hard boundary. Different textbooks and references disagree on whether to include certain elements (especially Zn/Cd/Hg, or Cu/Ag/Au, Po, etc.). However, many sources emphasize a “core set” that is almost always included.

In most engineering/materials contexts, the elements most often treated as post-transition metals (or as the core set) are:

Al, Ga, In, Sn, Tl, Pb, Bi (sometimes with Po added)

A common consensus is that Ga, In, Sn, Tl, Pb, Bi form the core set.

 

Typical shared features of post-transition metals

Post-transition metals are often grouped separately because, compared with typical transition metals, they more commonly show these features:

  1. Closer to the metal–nonmetal boundary: their structures/bonding more readily show stronger directionality and increased covalent character. Many systems show amphoteric oxides/hydroxides and anionic complexes (e.g., aluminate, stannate, etc.).
  2. Oxidation states are more “main-group-like”: unlike typical transition metals, their chemistry is not primarily driven by partially filled d orbitals that enable rich variable valence and coordination chemistry (though they can still form complexes).
  3. Inert pair effect: for heavier p-block metals (especially Tl, Pb, Bi, and in part Sn), the outer ns² electron pair is often “less willing” to participate in bonding, making lower oxidation states more stable: Tl(I) is more common than Tl(III), Pb(II) more common than Pb(IV), Bi(III) more common than Bi(V), while Sn(II)/Sn(IV) are both common (with stability/reactivity depending on conditions). This also explains why these elements often exhibit lone-pair-related structural effects and pronounced differences in hydrolysis/coordination behavior.

For comparison: IUPAC defines a transition element as an element whose atom has an incomplete d subshell, or that can form cations with an incomplete d subshell. Post-transition metals generally do not meet this criterion (or at least, it is not their primary chemical driver).

 

What are post-transition metal salts?

Post-transition metal salts are ionic compounds (salts) built around cations derived from post-transition metal elements (e.g., Al³, Sn²⁺/Sn⁴⁺, Pb²⁺, Bi³⁺, etc.) paired with anions (Cl, NO₃⁻, SO₄²⁻, RCOO, OH, halide-complex anions, etc.). In many real-world contexts, this also includes their salt forms in solution and the associated hydrolysis/complexation equilibria.

In reagent/engineering terms, this typically means a class of halides, nitrates, sulfates, carboxylates, oxides/hydroxides, and their hydrates/complexed forms, sold and used as metal sources. In the solid state and in solution, they may appear as ionic, molecular, polymeric, or complexed structures, depending on composition and conditions.

These salts are often treated in engineering as “weighable, soluble/formulatable, convertible metal sources”, used to:

  1. Provide metal ions (for reactions/catalysis/complexation)
  2. Serve as precursors (thermal decomposition / hydrolysis / precipitation / sol–gel → oxides, sulfides, halide films, powders)
  3. Act as functional additives (flocculation, stabilization, flame retardancy, pigments, plating, electronic-material formulations, etc.)

 

Are they important? Why?

Yes. They support key industrial value chains including displays, semiconductors, soldering/interconnects, electrochemical energy storage, water treatment, alloys, and lead-free substitution materials.

  1. Indium (In): one of the major long-standing uses is ITO (indium tin oxide) transparent conductive films, widely used in flat-panel displays and touch interfaces; also used in some alloys/solders and in compound semiconductor/materials fields.
  2. Gallium (Ga): GaN is central to LEDs/laser diodes, power electronics, and RF electronics; GaAs is used in various compound semiconductor devices.
  3. Tin (Sn): applications mainly concentrate in tinplate/packaging, solders and alloys, and the broader chemical supply chain (“tin chemicals” as a major source stream).
  4. Lead (Pb): consumption is highly concentrated in lead–acid batteries; use in non-battery applications (paints, gasoline additives, solders, water systems, etc.) has declined long-term due to regulation (shares vary by year/region).
  5. Aluminum salts (e.g., aluminum sulfate, polyaluminum chloride): widely used as coagulants/flocculants in drinking water and wastewater treatment; performance depends strongly on pH, alkalinity, and dosing conditions.
  6. Bismuth (Bi): often considered one option for lead replacement in metallurgy/alloys (requires evaluation of performance and recycling chain); bismuth salts also have established use in gastrointestinal medicines.
  7. Thallium (Tl): applications are more specialized (infrared optics, gamma detection, etc.); due to high toxicity and compliance constraints, it usually appears only in controlled R&D or specialized supply chains.

 

Where are they used, and what roles do they play?

Category

Typical elements/chemical forms (examples)

Typical materials/scenarios

Main role

Selection tips

A Electronics & optoelectronics

In/Sn salts (solution metal sources); ITO/IGZO/FTO oxide systems (targets/films); organogallium precursors TMGa/TEGa (epitaxy)

ITO transparent electrodes; IGZO TFT backplanes; CIGS thin-film PV; GaN/GaAs epitaxy

Upstream metal sources for films/semiconductors

For solution routes: solubility/hydrolysis; for epitaxy: volatility/purity; PVD often corresponds to oxide target systems

B Interconnects & alloys

Sn-based alloys; Bi alloy additives

Solders (incl. lead-free), low-temp soldering; free-cutting alloys/steels; lead-free substitution

Connecting, tuning properties, replacing Pb

Focus on alloy system and melting-point window; Bi often used for lead-free substitution and machinability improvement

C Energy & electrochemistry

Pb/PbO; oxides/alloys/doping precursors of Sn/Bi/In/Ga

Lead–acid batteries; selected electrodes/catalysis/conductive oxides (often niche or R&D adoption)

Battery main chain + building blocks for new systems

Emphasis: Pb–acid is mature bulk; others often require system-/form-/purity-specific selection

D Water treatment & environment

Al(SO) (alum/aluminum sulfate); PACl/PAC (pre-hydrolyzed polyaluminum species)

Drinking water/wastewater coagulation for turbidity removal; removal of colloids/organics

Aggregate particles so they settle/filter out

Mechanisms often summarized as charge neutralization + sweep flocculation; strongly dependent on pH/alkalinity/dose

E Organic synthesis & catalysis

AlCl, GaCl, InCl, SnCl (Lewis acids); SnCl (reducing); some Bi(III) salts (Lewis acid under mild conditions)

Activating carbonyls/epoxides, improving selectivity, widening process window

Faster/more selective/more scalable reactions

Prioritize: oxidation state (Sn(II) vs Sn(IV)), moisture sensitivity, coordination/side-reaction risk

F Pharma & life science

Bismuth salts such as bismuth subsalicylate (GI drugs); Al(OH), aluminum phosphate, etc. (vaccine adjuvants)

GI formulations; vaccine adjuvants and biologics formulations

Active ingredient or functional excipient

Safety note: large differences by element/form; both Al-salt adjuvants and Bi salts have mature uses, but not a “naturally safe” label

 

How to classify them: what type of post-transition metal salt is it, and how should it be used?

Level

What to look at

What you can conclude

Common examples

Step 1 Element

Element symbol/metal name: Al, Ga, In, Sn, Tl, Pb, Bi

Big picture: value-chain use + compliance/toxicity tier

In → displays/ITO; Ga → GaN/GaAs; Sn → solder/chemicals; Pb → batteries; Al → water treatment; Bi → lead-free substitution/drugs

Step 2 Valence (oxidation state)

(III)/(II)/(IV)/(I) or “Sn(II)”, “Sn(IV)”, etc.

Reactivity/stability framework: redox, Lewis acidity, hydrolysis tendency

Sn(II) is often more reducing and easier to oxidize; Sn(IV) is more stable and more strongly Lewis acidic; Tl often +1; Pb often +2; Bi often +3

Step 3 Anion (salt form)

Cl / Br / NO₃⁻ / SO₄²⁻ / OAc (acetate) / RCOO / OH

Solubility, moisture sensitivity, suitability as a solution metal source

Anhydrous AlCl is strongly hygroscopic and hydrolyzes readily; Pb(NO) is a common soluble Pb source; sulfates/carbonates often lean toward precipitation/ceramic routes

Step 3.5 Hydration/solvation

anhydrous, ·xHO, ·MeCN, solution, etc.

Same “name” can differ in effective metal content, activity, and exothermic hydrolysis behavior

“BiCl₃” vs “BiCl₃·xHO; anhydrous AlCl reacts exothermically with water; hydrated metal nitrates are commonly water-containing

 

Element–valence–typical forms–selection points

Element

Common valence states

Typical examples

Common roles

Selection points

Al

+3

AlCl; Al(SO); PAC

Lewis acid/catalysis; water-treatment coagulation; inorganic precursor

In water systems: focus on hydrolysis/alkalinity window; anhydrous halides are strongly hygroscopic

Ga

+3

GaCl, Ga(NO); organogallium precursors (epitaxy)

Upstream metal sources for optoelectronics/semiconductors

Electronic-grade routes emphasize purity and precursor form

In

+3

InCl, In(NO); complex precursors

ITO/display-related; materials precursors

Solution routes: watch hydrolysis/complexation and impurity control

Sn

+2/+4

SnCl, SnCl; organotin/tin carboxylates

Solders/alloys; materials precursors; selective reagents

First separate Sn(II) vs Sn(IV) (very different reactivity)

Tl

+1/+3

TlNO, TlCl

Limited specialized uses/research

Highly toxic and highly constrained; compliance first

Pb

+2 (rarely +4)

Pb(NO), Pb(OAc), PbO

Lead–acid battery chain; regulated uses declining

In most contexts: recognize Pb(II) dominance and compliance limits

Bi

+3

Bi(NO), BiCl; some pharmaceutical salts

Lead-free alloy additive; catalysis/drugs

Bi(III) dominates; common “basic salts/oxyhalides” as intermediate forms

 

Representative Product Classification Tables for Post-Transition Metals (Tables 1–4)

Quick Guide to the Four Product Tables

  1. Table 1 | Pb (Lead): Lead oxides / lead-salt conversion chemistry, lead halides (PbCl / PbBr / PbI), and the organolead oxidant lead tetraacetate. Toxicity and regulatory compliance must be confirmed first.
  2. Table 2 | Sn (Tin): Tin halides and tin oxides (SnO / SnO), reducing Sn(II) salts (e.g., SnCl), and organotin catalysts (DBTDL, stannous 2-ethylhexanoate).
  3. 3. and as bismuth precursors.
  4. Table 4 | In / Ga / Tl / Al + ITO + Standards: Transparent conductors / semiconductors and thin-film deposition (ALD/MOCVD), high-purity precursors, plus various standard solutions / thermal-analysis standards. Tl is extremely toxic and is limited to compliant materials research.

How to Choose Quickly Within the Tables

  1. For bulk materials: prioritize oxides / functional oxides (e.g., ITO, InO, GaO, SnO, BiO).
  2. For precursors / solution routes: prioritize nitrates / halides / complexes (acac); for moisture-sensitive systems choose ultra-dry / anhydrous / high-purity grades.
  3. For deposition (ALD/MOCVD): prioritize organometallics (e.g., TMA, TEAl, TMGa/TEGa, TEIn).
  4. For calibration / quantification: choose standard solutions / thermal-analysis standards (not primary material feedstocks).

 

Table 1 | Pb (Lead) System (Including Organolead Reagents)

Category

CAS No.

Aladdin Cat. No.

Name

Specification / Purity

Application or Key Features (Post-transition-metal related)

Pb (Lead) | Metal (foil)

7439-92-1

L433425

Lead foil

Analytical foil, ~0.25 mm thick

Typical metallic lead foil: used for analytical reference, shielding/electrodes/material comparison, etc.; a “form factor” supply of the post-transition metal Pb.

Pb (Lead) | Metal (powder)

7439-92-1

L105392

Lead powder

≥99.95% metals basis

Pb metal source (powder form): for alloys/material preparation, powder metallurgy, and lab formulation benchmarking (particle size and surface oxide layer affect reactivity/sintering); also used in research formulations for shielding/composites (note lead toxicity and compliance).

Pb (Lead) | Oxide

1317-36-8

L141267

Lead(II) oxide, yellow

Orthorhombic, 99.97% metals basis

Typical Pb(II) oxide metal source; for glass/ceramic glazes, precursor to lead salts/lead-oxide systems, and lead-based functional materials (note toxicity and environmental restrictions).

Pb (Lead) | Mixed-valence oxide (red lead)

1314-41-6

L112926

Lead(II,IV) oxide (PbO)

AR, ≥95%

PbO (red lead): lead-oxide system/material precursor; also used as a reference in lead chemistry/pigment/protective systems (note toxicity).

Pb (Lead) | Oxide (PbO)

1309-60-0

L753005

Lead dioxide

≥99.9% metals basis

Pb(IV) oxide: strong oxidant; relevant to electrode materials (e.g., lead–acid systems, electrochemical reference); note lead toxicity and oxidizing hazard.

Pb (Lead) | Carboxylate (acetate)

6080-56-4

L112922

Lead(II) acetate trihydrate

Premium grade, ≥99.5%

Common soluble Pb(II) metal source: for preparing other lead salts/lead oxides, precursor for materials synthesis; also used in complexation/precipitation chemistry (note toxicity).

Pb (Lead) | Carbonate

598-63-0

L433042

Lead(II) carbonate

Analytical grade, ACS, premium

Typical sparingly soluble Pb(II) salt/lead source: for lead-salt conversions, ceramics/inorganic pigments, and precursor studies (note toxicity and regulations).

Pb (Lead) | Basic salt (basic carbonate)

1319-46-6

L105147

Basic lead carbonate

AR, ≥99%

Common “lead white”/basic lead carbonate: pigment/inorganic precursor and lead-salt conversion chemistry; lead toxicity and regulatory restrictions are significant.

Pb (Lead) | Nitrate (strong oxidizer)

10099-74-8

L431226

Lead(II) nitrate (explosive precursor)

Ph.Eur, analytical grade, ACS, premium

Typical soluble Pb(II) salt / oxidizing nitrate: used to prepare PbO/PbX and other lead compounds/material precursors (note oxidizing hazard and safety/compliance).

Pb (Lead) | Sulfate

7446-14-2

L112940

Lead sulfate

PrimorTrace™, ≥99.999% metals basis

High-purity PbSO: sparingly soluble lead salt/reference material; used for lead-salt conversion, material benchmarking, and precipitation chemistry studies (note lead toxicity).

Pb (Lead) | Halide (chloride)

7758-95-4

L407489

Lead(II) chloride

PrimorTrace™, ultra-dry, ≥99.99% metals basis

High-purity PbCl metal source: for lead-halide materials / lead-halide perovskite research and lead-salt conversion; note toxicity and compliance.

Pb (Lead) | Halide (bromide)

10031-22-8

L119346

Lead(II) bromide

PrimorTrace™, ≥99.999% metals basis

High-purity PbBr precursor: commonly used in lead-halide perovskite/optoelectronic materials and lead-salt routes; impurities/moisture strongly affect device/optical performance.

Pb (Lead) | Halide (high-purity iodide)

10101-63-0

L292078

Lead(II) iodide

PrimorTrace™, ultra-dry, ≥99.999% metals basis

High-purity PbI precursor: closely tied to lead-halide optoelectronic/semiconductor materials (e.g., perovskite precursor routes); ultra-dry grade and trace control are key to device consistency.

Pb (Lead) | Organolead reagent (strong oxidant)

546-67-8

L106810

Lead tetraacetate

AR, with 4–10% glacial acetic acid stabilizer

Classic oxidant/cleavage reagent in organic synthesis (Pb(IV) reagent); glacial acetic acid as stabilizer; strict attention required for toxicity and waste disposal.

 

Table 2 | Sn (Tin) System (Including Organotin Catalysts)

Category

CAS No.

Aladdin Cat. No.

Name

Specification / Purity

Application or Key Features (Post-transition-metal related)

Sn (Tin) | Metal (powder)

7440-31-5

T141462

Tin powder

For elemental analysis

Sn metal source / reducing metal powder: for elemental analysis, alloy/material preparation, and reduction reactions; particle size and surface oxide affect activity.

Sn (Tin) | Oxide

18282-10-5

T432252

Tin(IV) oxide

Basic grade, for preparation

Typical SnO precursor / functional oxide: common in gas-sensing materials, catalysis, and transparent-conductor related systems; also used as a filler and for mixed-oxide preparation.

Sn (Tin) | Oxide (Sn(II))

21651-19-4

T475191

Tin(II) oxide

PrimorTrace™, ≥99.99% metals basis

SnO (stannous oxide): for tin-oxide materials, redox/valence-controlled synthesis; high purity helps phase purity and electrical consistency.

Sn (Tin) | Sulfate (Sn(II))

7488-55-3

S112918

Stannous sulfate

AR

SnSO: common Sn(II) metal source / reducing salt; used for tin-salt conversion and precursor preparation.

Sn (Tin) | Halide (tin tetrachloride, crystalline)

10026-06-9

S116324

Tin(IV) chloride, crystalline

Premium grade, ≥99%

Typical Sn(IV) precursor; used for SnO/tin-based materials and as a Lewis-acid/catalysis-related precursor (moisture-sensitive; control humidity).

Sn (Tin) | Halide (tin tetrachloride, Sn(IV))

7646-78-8

T433714

Tin(IV) chloride

PrimorTrace™, ≥99.995% metals basis

High-purity SnCl: common precursor for SnO/tin-based materials and catalysis; moisture-sensitive; ultra-dry/high purity aids controlled synthesis.

Sn (Tin) | Halide (stannous salt)

7772-99-8

T433980

Tin(II) chloride

Anhydrous grade, for synthesis

Typical Sn(II) reducing metal salt: widely used as a reductant and tin source in organic/material synthesis; anhydrous grade benefits moisture-sensitive systems.

Sn (Tin) | Halide (hydrated stannous salt)

10025-69-1

T478535

Tin(II) chloride dihydrate

Reagent grade, 98%

Common soluble Sn(II) tin source: broad use in reduction and coordination chemistry; dihydrate dissolves more readily for solution prep (oxygen/water sensitive—control conditions).

Sn (Tin) | Halide (bromide, Sn(II))

10031-24-0

T302028

Tin(II) bromide

≥99%

SnBr: Sn(II) halide metal source / reducing salt; used in tin halide and coordination/synthesis systems.

Sn (Tin) | Halide (fluoride, Sn(II))

7783-47-3

T195033

Tin(II) fluoride

≥99%

SnF: Sn(II) fluoride metal source; relevant to fluorine chemistry/material precursors and specific formulation systems.

Sn (Tin) | Halide (iodide, Sn(II))

10294-70-9

T292327

Tin(II) iodide

PrimorTrace™, ultra-dry, ≥99.99% metals basis

High-purity SnI precursor: used for tin iodide/tin-halide semiconductors and materials synthesis; ultra-dry grade suits moisture-sensitive routes and trace control.

Sn (Tin) | Halide (tin tetraiodide)

7790-47-8

T195043

Tin(IV) iodide

Anhydrous, PrimorTrace™, ≥99.998% metals basis

High-purity Sn(IV) halide precursor: for high-purity tin compounds/semiconductors and materials synthesis; trace control suits electronics/optoelectronics.

Organotin | Catalyst (DBTDL)

77-58-7

D100274

Dibutyltin dilaurate (DBTDL)

≥95%

Classic organotin catalyst: promoter for polyurethane and silicone-rubber condensation curing; sensitive to regulations/toxicology—watch substitution trends.

Organotin | Catalyst (stannous 2-ethylhexanoate / stannous octoate)

301-10-0

T100108

Stannous 2-ethylhexanoate

≥95%

Common Sn(II) organocarboxylate catalyst: for polyester polycondensation and polyurethane/silicone systems; a “soluble Sn(II) catalyst form” that is easy to dose and disperse.

 

Table 3 | Bi (Bismuth) System

Category

CAS No.

Aladdin Cat. No.

Name

Specification / Purity

Application or Key Features (Post-transition-metal related)

Bi (Bismuth) | Metal (granules)

7440-69-9

B109170

Bismuth granules

PrimorTrace™, ≥99.999% metals basis, 1–6 mm

Ultra-high-purity Bi metal source: for alloys/targets/melting and materials preparation; granules are convenient for weighing and melt processing.

Bi (Bismuth) | Oxide (nano)

1304-76-3

B431714

Bismuth(III) oxide

Nanopowder, ≥99.8% trace metals basis, 100–500 nm

Common BiO functional oxide: used in ceramics/glass modification and research on photocatalysis/ion conductors; trace control helps electrical/optical consistency.

Bi (Bismuth) | Halide (chloride)

7787-60-2

B100338

Bismuth(III) chloride

Reagent grade

Common Bi(III) metal source: for preparing bismuth salts/bismuth oxides, exploring Lewis-acid/catalysis systems, and materials synthesis.

Bi (Bismuth) | Nitrate

1304-85-4

B431716

Bismuth(III) nitrate

Ph.Eur, premium reagent, analytical grade, basic

Soluble Bi(III) salt precursor: used for BiO/basic bismuth salts, catalysis, and materials; the basic form relates to hydrolysis/coordination behavior.

Bi (Bismuth) | Nitrate (pentahydrate)

10035-06-0

B110814

Bismuth(III) nitrate pentahydrate

PrimorTrace™, ≥99.99% metals basis

Common soluble Bi(III) precursor: for BiO, basic bismuth nitrate, etc.; widely used in photocatalysis/functional-ceramic precursor routes.

Bi (Bismuth) | Carboxylate (acetate)

22306-37-2

B303104

Bismuth(III) acetate

PrimorTrace™, ≥99.99% metals basis

Convertible Bi(III) metal source: for bismuth oxides/basic bismuth salts and materials precursors; organic-acid salts are convenient in solvent-based processing.

Bi (Bismuth) | Basic halide (oxychloride)

7787-59-9

B304629

Bismuth oxychloride

≥99%

BiOCl: a common layered bismuth oxyhalide; used in photocatalysis, pigments/pearlescent effects, and precursor studies.

Bi (Bismuth) | Organic acid salt (subsalicylate)

14882-18-9

B107666

Bismuth subsalicylate

≥97%

Bi organic-acid/basic bismuth salt system: common in pharma and bismuth-source studies; can also serve as a conversion precursor to other bismuth compounds.

 

Table 4 | In / Ga / Tl / Al Systems + ITO + Standards

Category

CAS No.

Aladdin Cat. No.

Name

Specification / Purity

Application or Key Features (Post-transition-metal related)

In (Indium) | Reference material (thermal analysis)

7440-74-6

I119584

Thermal analysis reference material (indium)

Melting point: 156.52 °C

Common metal standard for DSC/DTA temperature/enthalpy calibration; post-transition metal In used as a “high-purity fixed point” for instrument metrology.

In (Indium) | Halide (hydrate)

10025-82-8

I431124

Indium(III) chloride hydrate

~39% In basis, 2–3 mol/mol HO

Common In(III) metal source: Lewis acid for coordination/organic synthesis and precursor for indium oxide/indium sulfide, etc.; hydrate form facilitates dissolution and solution preparation.

In (Indium) | Halide (high-purity tribromide)

13465-09-3

I290921

Indium(III) bromide

Ultra-dry, ≥99.95% metals basis

High-purity In(III) source: for high-purity indium inorganic/organometallic routes and electronic-material precursors; ultra-dry grade suits moisture-sensitive synthesis.

In (Indium) | Nitrate (hydrate)

207398-97-8

I118831

Indium nitrate hydrate

PrimorTrace™, ≥99.999% metals basis

High-purity soluble In(III) source: for indium oxides/indium salts, sol–gel and impregnation precursors; hydrate form eases solution preparation.

In (Indium) | Oxide (nano InO)

1312-43-2

I105868

Nano indium oxide

PrimorTrace™, ≥99.99% metals basis, <50 nm (TEM)

InO nanopowder: widely used in transparent conductors, gas sensing, and catalysis; particle size affects dispersion, sintering, and conductive networks.

In (Indium) | β-diketonate complex (acac)

14405-45-9

I465809

Indium(III) acetylacetonate

PrimorTrace™, ≥99.99% metals basis

Typical In(acac) precursor: commonly used for solgel, spray pyrolysis, thin-film coating/deposition, etc.

In (Indium) | Organometallic (MOCVD precursor)

923-34-2

T770767

Triethylindium

≥99.999% metals basis

Typical In source for MOCVD/epitaxial deposition (e.g., InP/InAs/InGaAs systems); high purity strongly impacts epitaxial defects and electrical properties.

In–Sn (Indium–tin) | Functional oxide (ITO)

50926-11-9

I432805

Indium tin oxide

Nanopowder, <50 nm

Typical transparent conductive oxide (TCO): for transparent electrodes, display/PV/sensor conductive coatings; particle size affects dispersion, sintering, and conductive pathways.

Ga (Gallium) | Analytical standard solution

7440-55-3

G115414

Gallium standard solution

Analytical standard, 1000 µg/mL in 1 mol/L HCl

Trace Ga calibration: for quantifying Ga in semiconductor/material samples and method development.

Ga (Gallium) | Halide (anhydrous chloride)

13450-90-3

G196258

Anhydrous gallium(III) chloride

PrimorTrace™, ≥99.999% metals basis

High-purity GaCl (Lewis acid / Ga source): for coordination/organic synthesis and gallium-compound preparation; anhydrous high purity suits trace-sensitive and moisture-sensitive reactions.

Ga (Gallium) | Halide (high-purity bromide)

13450-88-9

G302444

Gallium(III) bromide

Ultra-dry, ≥99.999% metals basis

High-purity Ga(III) source: for Ga compound/semiconductor precursor routes; ultra-dry grade suits moisture-sensitive/high-purity synthesis.

Ga (Gallium) | Halide (iodide)

13450-91-4

G284076

Gallium(III) iodide

PrimorTrace™, ultra-dry, ≥99.99% metals basis

High-purity GaI precursor: for gallium-halide/electronic-material chemistry and inorganic synthesis; ultra-dry grade benefits moisture-sensitive systems.

Ga (Gallium) | Nitrate (hydrate)

69365-72-6

G118483

Gallium(III) nitrate hydrate

PrimorTrace™, ≥99.999% metals basis

High-purity soluble Ga(III) salt: for GaO/gallium salts and materials precursors; common Ga source for aqueous processing.

Ga (Gallium) | Sulfate (hydrate)

13780-42-2

G190759

Gallium sulfate hydrate

PrimorTrace™, ≥99.999% metals basis

High-purity Ga(III) salt: gallium source / solution precursor; suited for sulfate-based systems or syntheses requiring specific ionic strength.

Ga (Gallium) | Sulfate (anhydrous / labeled (III))

13494-91-2

G475156

Gallium(III) sulfate

PrimorTrace™, ≥99.99% metals basis

Ga(III) sulfate: common for solution preparation and inorganic synthesis; suited for sulfate systems or routes controlling coordination environment.

Ga (Gallium) | Oxide (GaO)

12024-21-4

G110982

Gallium oxide

PrimorTrace™, ≥99.999% metals basis

Ultra-high-purity GaO functional oxide: common in wide-bandgap semiconductors/transparent electronics; high purity improves electrical/optical consistency.

Ga (Gallium) | β-diketonate complex (acac)

14405-43-7

G107856

Gallium(III) acetylacetonate

PrimorTrace™, ≥99.99% metals basis

Typical Ga(acac) precursor: used for GaO/gallium-based films and powders (solution routes, coating, thermal decomposition, etc.).

Ga (Gallium) | Organometallic (MOCVD precursor)

1115-99-7

T475958

Triethylgallium

Packaged for deposition systems

Typical Ga source for MOCVD/epitaxial deposition (GaAs/GaN-related research); highly volatile/reactive; packaging is designed for deposition delivery.

Ga (Gallium) | Organometallic (MOCVD precursor)

1445-79-0

T432113

Trimethylgallium

Packaged for deposition systems

Typical MOCVD Ga source: for GaN/GaAs films/epitaxy; oxygen/moisture sensitive and supplied for system-level delivery.

Tl (Thallium) | Halide (high-purity bromide)

7789-40-4

T578964

Thallium(I) bromide

Ultra-dry, ≥99.998% metals basis

Tl(I) halide crystal/salt precursor: relevant to Tl-halide materials for infrared optics and radiation detection (Tl is highly toxic; strict compliance required).

Tl (Thallium) | Halide (iodide)

7790-30-9

T292456

Thallium iodide

PrimorTrace™, ultra-dry, ≥99.99% metals basis

High-purity TlI: used in Tl-halide crystal materials for infrared optics/radiation detection; strict safety and regulatory compliance required due to extreme toxicity.

Al (Aluminum) | Oxide support (porous alumina)

1344-28-1

A1492668

Activated alumina balls

For catalyst supports

Typical catalyst support/adsorbent: for metal loading, drying/dehydration, and purification adsorption; pore structure and surface area govern loading and mass transfer.

Al (Aluminum) | Hydroxide

21645-51-2

A657564

Aluminum hydroxide

For preparing alumina

AlO precursor: calcination yields alumina; also common in inorganic fillers/flame retardancy systems and aluminum-salt preparation routes.

Al (Aluminum) | Halide (hydrate)

7784-13-6

A475793

Aluminum chloride hexahydrate

High purity, reagent grade, ≥99%

Common Al(III) salt: for preparing aluminum-salt solutions and hydrolysis/precipitation syntheses; hydrate chloride is sensitive to acidity and complexation.

Al (Aluminum) | Sulfate

10043-01-3

A101186

Aluminum sulfate

Anhydrous, ≥99.95% metals basis

Common Al(III) salt: for water-treatment flocculation, papermaking, inorganic synthesis, and alumina-route precursors; high purity suits materials/analytical uses.

Al (Aluminum) | Fluoride

7784-18-1

A105069

Aluminum fluoride

Anhydrous, ≥99.9% metals basis

Typical Al–F inorganic salt: fluoride-chemistry/inorganic-synthesis precursor; also linked to aluminum electrolysis flux/catalyst-support modification in some systems.

Al (Aluminum) | Nitrate (hydrate)

7784-27-2

A434090

Aluminum nitrate nonahydrate

Analytical grade, premium

Common soluble Al(III) salt: for inorganic synthesis/sol–gel precursors and analytical reagents; hydrate form facilitates solution preparation and impregnation.

Al (Aluminum) | Halide (high-purity iodide)

7784-23-8

A434022

Aluminum iodide

PrimorTrace™, anhydrous, ≥99.999% metals basis, powder

High-purity Al(III) halide / Lewis-acid-type precursor: for high-purity inorganic synthesis and Al–halide chemistry; anhydrous high purity helps trace control.

Al (Aluminum) | Halide solution (Lewis acid)

7727-15-3

A433866

Aluminum bromide solution

Anhydrous, 1.0 M in dibromomethane

Typical strong Lewis acid: promotes Friedel–Crafts, halogenation, rearrangements, etc.; solution form enables accurate dosing and anhydrous use.

Al (Aluminum) | Alkoxide

555-31-7

A432901

Aluminum isopropoxide (triisopropoxide)

For synthesis

Typical metal-alkoxide precursor: sol–gel preparation of alumina/composite-oxide films and powders; also used as an Al source in organic catalysis/transformations.

Al (Aluminum) | Basic salt (basic acetate)

142-03-0

A100197

Basic aluminum acetate

AR

Al(III) salt/complex system: for aluminum-salt solutions, precipitation/colloid systems, and materials precursors; basic salts are sensitive to pH/hydrolysis.

Al (Aluminum) | Polymeric salt (PAC)

1327-41-9

A190574

Polyaluminum chloride

AlO 28%

Typical water-treatment flocculant/polymeric Al salt: dominated by multinuclear hydroxy-aluminum species; widely used in engineering, with emphasis on effective AlO content.

Al (Aluminum) | Analytical standard solution

7429-90-5

A105852

Aluminum standard solution

Analytical standard, 100 µg/mL in 5% HCl

For ICP/AAS/IC calibration; acidic matrix (5% HCl) stabilizes metal ions and supports traceable quantification.

Al (Aluminum) | Organometallic (ALD/MOCVD precursor)

75-24-1

T433589

Trimethylaluminum (TMA)

Packaged for deposition systems

Classic ALD precursor for AlO films; also used as a co-catalyst/scavenger in polymerization (highly pyrophoric/reactive; requires dedicated gas handling).

Al (Aluminum) | Organometallic (TEAl solution)

97-93-8

T434622

Triethylaluminum solution

25 wt.% in toluene

Typical Ziegler–Natta/metallocene co-catalyst & scavenger; highly pyrophoric/reactive; solution form aids metering (requires inert handling).

Note: The above are representative Aladdin catalog numbers. For more products, please refer to the product tables at the end of this article or search the official website by CAS number or product name.


Aladdin: https://www.aladdinsci.com/

Categories: Technical articles
Explore topics: Post-transition metals

Da — when not otherwise indicated, molecular weight units are daltons.   Mw — weight-average molecular weight.   Mn — number-average molecular weight.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.

Cite this article

Aladdin Scientific. "Post-Transition Metals and Their Salts: A Classification Guide from Definitions to Value-Chain Applications (Including Product Lists in Tables 1–4)" Aladdin Knowledge Base, updated Jan 4, 2026. https://www.aladdinsci.com/us_en/faqs/post-transition-metals-and-their-salts-en.html
Was this article helpful? Yes No 0 out found this helpful

Shall we send you a message when we have discounts available?

Remind me later

Thank you! Please check your email inbox to confirm.

Oops! Notifications are disabled.