Technical articles

What Are Rare Earths? Material Logic of 17 Elements, an Application Map, and a Quick Guide to Aladdin Reagent Selection (Oxides/Salts/Metals/Standard Solutions/Dispersions)

What Are Rare Earths, Really? They Are Not “Earth”—They Are a Set of 17 Elements

“Rare Earth Elements (REEs)” commonly refers to the 15 lanthanides (La–Lu) plus yttrium (Y) and scandium (Sc)—17 elements in total. “Rare” does not mean “all of them have extremely low crustal abundance.” As a group, REEs are not exceptionally scarce; rather, they tend to occur in a dispersed manner, are tightly co-occurring in minerals, and have similar chemical behavior, making them difficult and costly to concentrate, separate, and purify. Therefore, a key bottleneck in the industrial chain lies in separation and purification.

It is also important to note the within-group differences: some heavy rare earths do sit at the low-abundance end; and Pm, although a lanthanide by definition, has virtually no natural abundance in the Earth’s crust.

List of Rare Earth Elements (17)

Category

Elements

Symbols

Light/Medium Lanthanides

Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium

La, Ce, Pr, Nd, Pm, Sm, Eu

Heavy Lanthanides

Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium

Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu

Lanthanide-like

Yttrium, Scandium

Y, Sc

Notes:

1. Y and Sc are often grouped as rare earths because their mineral occurrence and chemical behavior are similar to lanthanides (especially Y³), and they are frequently discussed within the same separation and refining value chain.

2. The light/medium/heavy grouping is one commonly used engineering convention; the exact grouping may vary by industry or statistical definitions.


Why “A Little Rare Earth” Can Change Materials a Lot: Three Fundamental Logics

The “Three Fundamental Logics” by Which REEs Tune Material Properties

Fundamental Logic

How It Manifests in Materials

The Most Common “Knobs” to Tune

Typical Application Scenarios

Tunable 4f/5d energy levels and valence states (magnetism/optics)

Luminescent centers, magnetic moments and anisotropy, electronic transitions; 4f–4f transitions are often narrow-line, while 5d–4f transitions are often broadband and more sensitive to the crystal field

Ion species and valence (e.g., Eu³/Tb³⁺/Ce³⁺/Eu²⁺), coordination environment/crystal-field strength, concentration quenching, reducing/oxidizing atmosphere

Phosphors (e.g., YAG:Ce), laser crystals, scintillators, permanent magnets/magneto-optical materials

“Lanthanide contraction”: ionic radii decrease gradually

Systematic changes in lattice parameters/solid solubility/phase-stability windows

Selecting different ions from La → Lu, site occupancy (A/B sites), co-doping

Structural stabilization, dielectric/ferroelectric tuning, crystal engineering

Ln³ as hard acids: more stable with hard bases (O²⁻/F) in crystal lattices

Oxygen vacancies/valence compensation/grain-boundary barrier modifications → affects ionic conductivity, loss, and interfacial behavior (solid-state defect chemistry dominated)

Dopant valence (3+ vs 4+), oxygen partial pressure/atmosphere, sintering schedule, anion environment (O²/F)

Oxygen-ion conductors, sensing ceramics, electrochemical devices, fluoride optical materials

Rare Earth Application Map

How to Read This Map: Five Core Roles of REEs in Materials and Devices

Role 1 — Emission/Energy-Level Center: RE ions provide characteristic emission (the “bulb filament” of optical functions).

Role 2 — Defect Controller: Introducing/tuning oxygen vacancies and carriers via charge compensation (core for electrochemistry/sensing).

Role 3 — Phase Stabilizer: Stabilizing certain structural phases or widening stability windows (e.g., bringing high-temperature phases down to lower temperatures).

Role 4 — Microstructure Engineer: Refining grains / modifying eutectics / forming stable intermetallics or precipitates (strength, creep, corrosion resistance).

Role 5 — Medical Isotope Platform: Acting as radionuclides/carrier-related materials in nuclear medicine.

Application Scenarios

Scenario

Common RE Elements / Chemical Forms (Selection Entry)

Main RE Role

Key Metrics (Examples)

Common Characterization/Verification

Key Process Window / Common Failure Modes (Pitfalls to Avoid)

High-temperature superconducting ceramics (REBCO/YBCO)

Y, Gd, Sm, Nd, etc.; targets/precursors: REO, REBaCuO₇₋x-related powders, thin-film sputtering targets

Site substitution; defects/flux pinning

Tc, Jc, trapped field, mechanical reliability

XRD, cryogenic transport, magnetic measurement (M–H), defect/texture imaging (SEM/TEM/EBSD)

Oxygen content + heat-treatment window determine Jc; weak links at grain boundaries, microcracks, insufficient texture → large performance scatter; bulk trapped-field strongly depends on temperature and reinforcement design

Oxygen-ion conductors (YSZ, etc.)

YO-doped ZrO (powders: YO, ZrO); ScO-doped systems also used

Defect control (oxygen vacancies) + phase stabilization

σ_ion, grain-boundary impedance, chemical/thermal stability

EIS (bulk vs GB), XRD, SEM/EDS, density

Si/Al/Ca impurities can form insulating GB phases → higher GB resistance; porosity/secondary phases → lower effective conductivity; sintering T/atmosphere critical. (YSZ = composition defines use): SOFC electrolytes often use 8 mol% YO (8YSZ); Y³ substituting Zr⁴⁺ introduces oxygen vacancies via charge compensation—key to high ionic conductivity.

YSZ structural ceramics (toughened zirconia)

YO-stabilized ZrO (powder grade)

Phase stabilization + transformation toughening

K_IC, strength, aging resistance

XRD (phase), mechanical tests, microstructure

Y-content window controls tetragonal stability; hydrothermal aging/phase transformation degrades properties; porosity & grain size are critical. (YSZ = composition defines use): Structural toughening typically uses a partially stabilized / metastable tetragonal window (not “more stabilized is better”); engineering practice often uses ~3 mol% YO (3Y-TZP) relying on stress-induced transformation for toughening.

YSZ thermal barrier coatings (TBC)

YSZ powders/spray powders; extendable to RE zirconates (e.g., La/Gd)

Low thermal conductivity + high-T phase stability

Thermal conductivity, thermal-cycle life, sintering resistance

Thermal cycling/thermal shock, phase analysis, porosity/crack network

Porosity architecture governs insulation and life; high-T sintering closes pores → higher k; CMAS attack/interface spallation are major failure drivers. (YSZ = composition defines use): In TBC engineering, 7 wt% or 7–8 wt% YO (7YSZ/78YSZ) is commonly used as the composition label for mainstream coating systems.

Piezoelectric/ferroelectric/electro-optic (PZT → PLZT)

LaO or La(NO)₃·xHO commonly used; Nd/Sm dopants also seen

Site occupancy + defect control + microstructure control (transparency/electro-optic)

d33, loss, transparency/electro-optic coefficient, stability

Dielectric spectra, P–E loops, transmittance, porosity quantification (microscopy/image analysis)

Porosity/secondary phases = immediate failure for transparent electro-optic behavior; volatile components, sintering atmosphere, heating profile are sensitive; over-doping → segregation/secondary phases. Transparent PLZT performance often depends not only on doping but even more on ultra-low porosity/scatterer suppression, requiring strong densification routes (e.g., hot pressing, HIP, or very tight sintering windows) to reduce residual pores below optically visible levels.

Microwave dielectric ceramics

Composite oxides involving La/Nd/Sm, etc.; precursors often REO or nitrates

Phase stability + lattice tuning

εr, Q×f, τf

Microwave resonance method, XRD (phase/refinement), grain/secondary phases (SEM/EDS)

Secondary phases, abnormal grain growth, glassy phases → strong Q degradation; formulation and sintering window (density/grain size) are strongly coupled

Gas-sensing ceramics (SnO/ZnO/LaFeO, etc.)

La/Nd/Sm, etc.; precursors: RE(NO)₃·xHO, RECl₃·xHO, REO

Morphology/defects/surface chemistry tuning

Sensitivity, selectivity, response/recovery, drift

Electrical response curves, surface analysis (XPS), morphology (SEM/TEM)

Humidity cross-sensitivity and long-term drift are common; over-sintering reduces surface area; noble metals/impurities may become the “true active centers,” causing irreproducibility

Varistor ceramics (ZnO varistors)

La/Pr micro-doping (depends on formulation); precursors: REO/nitrates

Grain-boundary barrier control

Nonlinearity coefficient α, breakdown/leakage, stability

I–V curves, GB phases/segregation (SEM/EDS)

Narrow doping window: excess dopant → lower α and degradation; sintering atmosphere and GB phase chemistry determine varistor behavior. REEs often act as trace co-dopants for GB barrier tuning; the base system is commonly co-designed with BiO, SbO, and acceptor/GB additives such as Co/Mn (varies significantly by process route).

Thermistor ceramics (PTC/NTC; BaTiO systems)

La/Ce/Sm/Dy/Y micro-doping (system-dependent); precursors: REO/nitrates

Carrier/defect and GB control

R–T curves, B value / resistance change near Curie point, aging

Resistance–temperature characteristics, microstructure, phase analysis

Over-doping may cause insulation or drift; GB glass phases/porosity lead to aging and batch variability

Permanent magnets (NdFeB/SmCo)

Nd/Pr metal or master alloy; Dy/Tb for coercivity; Sm metal for SmCo; RE hydrides/alloy powders also used

Large magnetic moment/anisotropy; heavy RE boosts coercivity (GB engineering)

Br, Hcj, (BH)max, temperature coefficient, corrosion resistance

Hysteresis loops (VSM), microstructure/GB phases (SEM/EPMA)

Dy/Tb raise Hcj but may reduce Br and increase cost; GB phases and oxygen control are decisive; corrosion is strongly linked to coating/impurities

Luminescent materials/phosphors (LED/displays)

YO, CeO, EuO, TbO, etc.; nitrate solution routes also common

RE ions as emission centers (4f/5d levels)

Emission peak, quantum efficiency, thermal quenching, lifetime, chromaticity

PL/PLE, integrating-sphere QE, lifetime, XRD

Transition-metal impurities quench; concentration quenching; valence sensitivity (Ce³/Ce⁴⁺) depends on atmosphere; particle size/coatings affect scattering and stability

Laser crystals / upconversion materials

Er/Yb/Tm/Ho, etc.; precursors: high-purity REO or salts

Energy-level transitions; upconversion/stimulated emission

Emission cross section, lifetime, threshold, thermal management

Spectra & lifetimes, impurity spectra, phase/defect characterization

Impurities and OH defects cause loss; concentration/co-doping ratio windows; crystal defects/stress cause scattering and cracking

CeO catalysis / oxygen storage (automotive exhaust, redox)

CeO (powders/nano), often with ZrO; precursors: cerium nitrate/ceria

Reversible valence + oxygen vacancies (OSC)

OSC, conversion, durability/sintering resistance

XPS (Ce³/Ce⁴⁺), TPR/TPD, BET, activity tests

Sintering reduces surface area; impurities/chloride residues harm activity and reproducibility; operating oxygen partial pressure controls valence/vacancies

Solid electrolytes / energy materials (La-containing systems)

Typical La-containing oxide electrolyte families (precursors: LaO/lanthanum nitrate, etc.)

Framework / ion-transport related tuning

Ionic conductivity, interfacial impedance, cycling stability

EIS, phase analysis, interface characterization

Secondary phases and GB impedance are major enemies; moisture/carbonation in air affects powders and interfaces; sintering schedule governs densification and GB chemistry

Al–Sc alloys

Sc metal/master alloy; ScO in certain metallurgical routes

Precipitation strengthening (AlSc) + recrystallization suppression

Strength, thermal stability, weldability/recrystallization behavior

TEM (precipitates), mechanical tests, microstructure after thermal exposure

Key is precipitate size/distribution and coarsening under exposure; Sc cost is high → manage dosage window + recovery/yield in process

Al–Ce alloys

Ce metal/master alloy; or CeO in certain routes

Stable intermetallic/eutectic microstructures, heat resistance

High-T strength, creep, microstructural scale

XRD, quantitative microstructure, creep/high-T tensile

Coarse eutectic/second phases limit toughness and room-temperature properties; refinement and thermal-exposure stability are key

Mg–RE alloys

Y/Nd/Gd metals or master alloys; salts usually not used

Strengthening phases + texture/creep control

Creep resistance, heat resistance, oxidation resistance

High-T mechanical tests, microstructure/phase analysis

Phase coarsening and oxidation dominate degradation; melt cleaning and inclusion control affect lifetime

Cu–RE alloys (casting purification/grain refinement)

Ce/La trace additions; metals or master alloys

Purification, grain refinement, microstructure improvement

Strength/ductility, wear, casting defects

Microstructure & inclusion analysis, mechanical tests

“Multiple-fold improvement” depends strongly on recipe and conditions; over-addition or poor inclusion control may backfire

Agriculture (highly debated)

Mostly La/Ce salts (strict regulation and assessment required)

Possible low-dose stimulation (biphasic response)

Yield/quality, accumulation & ecological risks

Field controls + long-term monitoring + food-chain exposure assessment

Strongly dependent on dosage, soil properties, and speciation; conclusions cannot be generalized; risk assessment must be embedded in boundary conditions. The so-called “low-dose stimulation / high-dose inhibition (hormesis)” is mainly a phenomenological description; evidence depends heavily on soil type, RE form, dose, and study design, and cannot be extrapolated across regions.

Medical Path A: nuclear-medicine radionuclides (more reliable)

Radiopharmaceuticals based on radioactive isotopes (within regulatory systems)

Diagnosis/therapy (dosimetry & targeting are central)

Imaging quality, therapeutic dosimetry, safety

Clinical evidence, dosimetry evaluation, regulatory compliance

Governed by drug/device regulations; do not replace clinical evidence with a “REE salts = anti-cancer” narrative. Clinical use is mostly regulated radionuclide formulations (e.g., Lu-177 radiopharmaceutical systems); evaluation focuses on dosimetry/targeting/safety and standardized workflows rather than “magic of the element.”

Medical Path B: non-radioactive RE complexes / imaging materials (research + established uses coexist)

Gd-complex–related contrast materials, RE nanoprobes, etc.

Imaging contrast/material platform

Stability, chelation strength, biocompatibility

Chemical stability/release evaluation, in vitro/in vivo validation

Risks are strongly tied to regulation; ligand stability and release risk must be clearly defined to avoid generalized claims. In clinical/translational contexts, emphasis is on high-stability chelation/complex systems, release-risk control, and regulatory safety evaluation pathways.


Research & Lab Selection Guide

Process Route → Recommended RE Reagent Forms

Target/Process

Recommended Form

Why It Fits Better

Common Pitfalls

Solid-state synthesis / ceramic sintering (bulk)

REO / CeO / YO

Thermally stable; straightforward weighing; easy stoichiometry control

Some REO absorb moisture/CO  stoichiometry drift and secondary phases

Sol-gel / co-precipitation / impregnation

RE(NO)₃·xHO

High solubility; homogeneous mixing; mature thermal decomposition route

Hydration number x can vary; nitrate decomposition gases affect porosity

Coordination chemistry / organic-phase nanochemistry

RECl₃·xHO / RE(acetate)

Commonly used for coordination reactions; good controllability

Cl residues may affect electrical properties/corrosion; hydrolysis/gelation under basic conditions

Fluoride materials / molten salts / optical fluorides

REF (preferably anhydrous/low-water)

Avoid OH defects; compatible with fluoride systems

Water/OH introduces optical loss and phase deviation

Alloy melting / master-alloy addition

RE metals / master alloys (e.g., Al–Sc)

Direct entry into molten-metal routes

Oxide inclusions, burn-off loss, recovery/yield, coarsening of second phases

Purity and Impurity Profiles

Three Common Purity Conventions

1. trace metals basis: emphasizes strict control of trace metallic impurities (most critical for optical/electrical/magnetic work)

2. REO/TREO basis: reported as rare-earth oxide content (common in the RE industry, ores/intermediates)

3. metals basis: reported as metal content (common in coordination chemistry, solution precursors, metal salts)

Application Scenario → Most Sensitive Impurities

Scenario

Most Sensitive Impurity Types

Why Sensitive

Luminescence / lasers / transparent ceramics

Fe, Cu, Ni, Co, Cr (transition metals)

Create absorption/quenching centers → directly reduce emission efficiency and transmittance

Dielectric / ferroelectric / microwave dielectrics

Si, Al, Ca, Na, K, Fe

Form grain-boundary phases / change defect states → higher loss, drift, lower Q

Ion conductors / electrochemistry (YSZ, etc.)

Si, Al, Ca, Fe, Cl/SO₄²⁻ residues

Raise GB resistance or introduce electronic conduction → poorer conductivity/stability

Catalysis / redox materials

Trace transition metals (any source)

May “seem to enhance activity” but kills reproducibility (impurities become true active centers)

Alloys / melting

O, N, H, S, P (gases/impurities)

Oxide inclusions, porosity, embrittlement, coarsening → lower strength/lifetime

Note: Purity conventions and test lists may differ by supplier and batch. Use the COA (Certificate of Analysis) impurity list and detection limits as the reference; metals basis often does not cover non-metal residues (e.g., C/S/Cl), which should be checked separately.


Risk & Compliance Checklist

Risk Source

Main Risk

Control Measures

RE powders/dust

Inhalation risk (occupational health literature suggests attention is warranted)

Local exhaust/ventilation hood, wet handling, appropriate respiratory protection, avoid airborne dry powders

Nitrates/strong acids

Oxidizing/corrosive hazards; thermal decomposition gases

Small-batch handling, corrosion-resistant containers, off-gas management and treatment during calcination

Ores/tailings/suspicious samples

Associated Th/U risk; TENORM management

Source traceability; handle/dispose per institutional radiation/regulated-waste rules

Waste liquids with heavy metals

Environmental discharge risk

Segregated collection, clear labeling, compliant disposal


Aladdin Representative Rare-Earth Product Classification Table

(Oxides/Salts/Metals/Standard Solutions/Nano Dispersions)

Quick Selection Checklist (Condensed)

Category

Preferred Scenarios

Key Selection Points (How to Choose)

Typical Notes / Common Pitfalls

RE oxides (PrimorTrace™/analytical grade/basic grade)

Solid-state reactions, ceramic sintering, glass/refractory formulations, catalysis/oxygen storage, optical host powders

Ultra-sensitive to impurities (luminescence/electrical/transparent ceramics) → PrimorTrace™; process screening/general prep → analytical/basic grades

Moisture/CO uptake  weighing drift; pre-dry if needed; seal storage

RE nitrates (hydrates; PrimorTrace™/high purity)

Sol-gel, co-precipitation, impregnation, solution doping, thermal decomposition to oxide precursors

Excellent water solubility and mixing; impurity-sensitive systems → PrimorTrace™; general use → high purity/AR

Often hydrates → crystal water affects stoichiometry; decomposition gas can alter pore structure/morphology

RE chlorides (anhydrous/hydrated; PrimorTrace™/high purity)

Solution precursors, halide routes, some coordination/organometallic routes (prefer anhydrous)

Water-sensitive coordination/organometallic → anhydrous; common solution routes → hydrated; impurity-sensitive → PrimorTrace™

Hydrates are strongly hygroscopic; Cl may cause corrosion/side reactions/residues  control via washing/heat treatment

RE metals (powder/ingot/chips/lumps; incl. REO-basis labeling)

Alloying additions, magnetic materials, sputtering/target feedstock, metal-state reduction/intermetallic studies

Powder → faster reaction/more uniform mixing; ingot/lump/chips → stable feeding for melting; oil-sealed ingots reduce oxidation

Easily oxidized (especially powders) → inert/sealed handling; “metals basis (REO)” is a reporting convention—do not misread as total impurity

RE standard solutions (elemental analysis/calibration)

ICP-OES/ICP-MS/AAS calibration, QC, spike recovery, method validation

Match acid matrix to sample digestion (e.g., 1.0 mol/L HNO, 10% HCl, 10% HNO)

Matrix mismatch causes matrix effects; if acid matrix not specified, confirm matrix matching first

RE nano dispersions (<100 nm; dispersions)

Coatings/films, composite fillers, catalyst supports, uniform introduction without separate dispersion steps

Check: particle size (<100 nm; BET), solids content (e.g., 5 wt%), dispersion medium (water/solvent)

Stability depends on pH/ionic strength/solvent exchange; shake/disperse thoroughly before use; consistency matters


Aladdin Representative Rare-Earth Product Classification Table

For more specifications, please refer to the full product list at the end, or search on the Aladdin website by product name/CAS.

Category

CAS No.

Aladdin Cat. No.

Name

Specification/Purity

Product Features or Applications

RE oxides (PrimorTrace™ ultra-high purity)

12060-08-1

S110936

Scandium(III) oxide

PrimorTrace™, ≥99.999% metals basis

Ultra-low impurity background; suitable for advanced optical/electronic materials, precise doping, and impurity-sensitive research systems

RE oxides (PrimorTrace™ ultra-high purity)

12037-01-3

T105880

Terbium oxide

PrimorTrace™, ≥99.999% metals basis

High-purity Tb source for phosphor/magneto-optical doping, precise composition control, and high-requirement analysis/material research

RE oxides (PrimorTrace™ high purity)

12064-62-9

G105875

Gadolinium oxide

PrimorTrace™, ≥99.99% metals basis

High-purity GdO for magnetic/neutron-absorption-related materials, optics, and precision doping

RE oxides (PrimorTrace™ high purity)

1313-97-9

N105307

Neodymium oxide

PrimorTrace™, ≥99.99% metals basis

High-purity NdO for lasers/optical glass, magnetic-materials research, and precise doping

RE oxides (PrimorTrace™ high purity)

12055-62-8

H105899

Holmium oxide

PrimorTrace™, ≥99.99% metals basis

Suitable for magnetic/spectroscopic materials research, precise doping, and impurity-sensitive systems

RE oxides (PrimorTrace™ high purity)

1308-96-9

E106508

Europium oxide

PrimorTrace™, ≥99.99% metals basis

Typical Eu source for luminescence; high purity improves reproducibility and lowers background for spectroscopy/PL research

RE oxides (PrimorTrace™ high purity)

1308-87-8

D105275

Dysprosium oxide

PrimorTrace™, ≥99.99% metals basis

High-purity DyO for magnetic materials, optics, and precision doping research

RE oxides (PrimorTrace™ high purity)

12032-20-1

L105574

Lutetium oxide

PrimorTrace™, ≥99.99% metals basis

Suitable for high-end optics, scintillators, ceramics, and precision doping

RE oxides (PrimorTrace™ high purity)

12037-29-5

P128241

Praseodymium oxide

PrimorTrace™, ≥99.99% metals basis

For functional ceramics, catalysis, and doping systems; suitable where impurity interference must be minimized

RE oxides (PrimorTrace™ high purity)

1314-37-0

Y118477

Ytterbium oxide

PrimorTrace™, ≥99.99% metals basis

High-purity YbO for NIR/luminescence and optical-materials doping with precise composition control

RE oxides (high-purity REO)

12036-44-1

T105902

Thulium oxide

≥99.99% (REO)

High-purity TmO for optical/luminescent/ceramic doping; REO basis supports comparison across RE oxide systems

RE oxides (analytical use/pellets)

1306-38-3

C124415

Cerium oxide

For elemental analysis, 1.5–2.5 mm

Granular form facilitates weighing/charging and elemental-analysis use; CeO is also used for polishing, catalysis, and oxygen-storage studies

RE oxides (analytical grade)

1314-36-9

Y431838

Yttrium oxide 99+

Analytical grade, ≥99%

Basic oxide for ceramics/refractories and optical/phosphor host/doping; suitable for routine analysis and formulations

RE oxides (basic preparative grade)

1312-81-8

L431805

Lanthanum(III) oxide

Basic grade, for preparation

Common base oxide for glass/ceramic modification, catalysis/oxygen-storage systems, and functional fillers; suitable for process screening and preparation

RE nitrates (hydrates; PrimorTrace™ ultra-high purity)

100641-16-5

L431221

Lutetium(III) nitrate hydrate

PrimorTrace™, ≥99.999% metals basis

High-purity Lu nitrate for solution routes and precision doping; nitrates often decompose to oxides upon calcination

RE nitrates (hydrates; PrimorTrace™ ultra-high purity)

35725-34-9

Y432655

Ytterbium(III) nitrate pentahydrate

PrimorTrace™, ≥99.999% metals basis

High-purity Yb nitrate for solution doping/precursors; note hydration water impacts stoichiometry and drying

RE nitrates (hydrates; PrimorTrace™ high purity)

94219-55-3

G189235

Hydrated gadolinium nitrate

PrimorTrace™, ≥99.99% metals basis

High-purity Gd nitrate for solution precursors and nitrate-to-oxide decomposition routes; suitable for precision doping

RE nitrates (hydrates; PrimorTrace™ high purity)

13494-98-9

Y118878

Yttrium nitrate hexahydrate

PrimorTrace™, ≥99.99% metals basis

Highly water-soluble; suitable for sol-gel/co-precipitation/impregnation; high purity helps lower defects in transparent-ceramic/optical systems

RE nitrates (hydrates; PrimorTrace™ high purity)

13759-83-6

S109297

Samarium(III) nitrate hexahydrate

PrimorTrace™, ≥99.99% metals basis

High-purity Sm nitrate for solution precursors/doping; mature nitrate decomposition route supports uniform oxide formation

RE nitrates (hydrates; PrimorTrace™ high purity)

10031-53-5

E196207

Europium(III) nitrate hexahydrate

PrimorTrace™, ≥99.99% metals basis

Suitable for solution doping of phosphors; hydration must be accounted for in stoichiometry

RE nitrates (hydrates; PrimorTrace™ high purity)

15878-77-0

P106056

Praseodymium(III) nitrate hexahydrate

PrimorTrace™, ≥99.99% metals basis

High-purity Pr nitrate for solution precursors/doping; nitrates enable uniform precursors and easy conversion to oxides

RE nitrates (hydrates; PrimorTrace™ high purity)

107552-14-7

S188988

Scandium(III) nitrate hydrate

PrimorTrace™, ≥99.99% metals basis (REO)

High-purity Sc nitrate for solution precursors and decomposition-to-oxide routes; better for impurity-sensitive systems

RE nitrates (hydrates; PrimorTrace™)

36548-87-5

T189124

Thulium(III) nitrate pentahydrate

PrimorTrace™, ≥99.9% metals basis

High-purity Tm nitrate for optical/luminescent doping in solution routes; store dry and account for hydrate mass

RE nitrates (hydrates; high purity)

10294-41-4

C431281

Cerium(III) nitrate hexahydrate

Ultra-pure grade

Highly water-soluble for impregnation/co-precipitation/sol-gel precursors; also used in Ce(III) coordination and catalytic precursor chemistry

RE nitrates (hydrates; high purity)

57584-27-7

T124613

Terbium(III) nitrate pentahydrate

≥99.9% metals basis

Water-soluble for Tb-doped precursors (phosphor/magneto-optical); easy conversion to oxides via nitrate decomposition

RE nitrates (hydrates; high purity)

100587-94-8

L475064

Lanthanum(III) nitrate hydrate

≥99.9% metals basis

Common for sol-gel/impregnation/co-precipitation; hydration degree may vary → watch stoichiometry drift

RE nitrates (hydrates; AR)

16454-60-7

N106057

Neodymium nitrate hexahydrate

AR, ≥99%

Routine high-purity soluble salt for solution routes/doping; account for crystal water in stoichiometry

RE chlorides (hydrates; PrimorTrace™ ultra-high purity)

10025-94-2

Y119237

Yttrium(III) chloride hexahydrate

PrimorTrace™, ≥99.999% metals basis

High-purity soluble Y source for solution processing (impregnation/co-precipitation/sol-gel) and high-end doping systems

RE chlorides (hydrates; PrimorTrace™ ultra-high purity)

20662-14-0

S475229

Scandium(III) chloride hexahydrate

PrimorTrace™, ≥99.999% metals basis

High-purity water-soluble Sc source for impurity-critical solution routes and advanced precursor systems

RE chlorides (hydrates; PrimorTrace™ ultra-high purity)

13798-24-8

T100635

Terbium chloride hexahydrate

PrimorTrace™, ≥99.999% metals basis

High-purity Tb salt for solution doping (phosphor/magneto-optical) and fine chemical research; hydrate mass must be handled carefully

RE chlorides (hydrates; PrimorTrace™ high purity)

13759-92-7

E119161

Europium(III) chloride hexahydrate

PrimorTrace™, ≥99.99% metals basis

High-purity Eu salt for solution doping/co-precipitation; account for hydrate stoichiometry and drying

RE chlorides (hydrates; PrimorTrace™ high purity)

15230-79-2

L119054

Lutetium(III) chloride hexahydrate

PrimorTrace™, ≥99.99% metals basis

High-purity Lu salt for solution routes and precision doping; minimizes impurity-driven secondary phases

RE chlorides (hydrates; PrimorTrace™ high purity)

20211-76-1

L189069

Lanthanum chloride hydrate

PrimorTrace™, ≥99.99% metals basis

High-purity La salt for impregnation/co-precipitation/sol-gel; hydrate water must be considered

RE chlorides (hydrates; PrimorTrace™ high purity)

10035-01-5

Y196893

Ytterbium(III) chloride hexahydrate

PrimorTrace™, ≥99.99% metals basis

High-purity Yb salt for solution precursors/doping; helps avoid impurity-driven quenching/secondary phases

RE chlorides (hydrates; high purity)

13450-84-5

G119153

Gadolinium(III) chloride hexahydrate

≥99.9% metals basis

Water-soluble for solution precursors (impregnation/co-precipitation/sol-gel); correct stoichiometry for hexahydrate

RE chlorides (hydrates; high purity)

13477-89-9

N123721

Neodymium(III) chloride hexahydrate

≥99.9% metals basis

Used for solution doping/precursors; strongly hygroscopic—handle and store dry

RE chlorides (hydrates; high purity)

14914-84-2

H119101

Holmium(III) chloride hexahydrate

≥99.9% metals basis

Ho source for solution processing and doping; high solubility supports homogeneous introduction

RE chlorides (hydrates; high purity)

19423-77-9

P168270

Praseodymium(III) chloride hydrate

≥99.9% metals basis

Soluble precursor for doping; hydrate water is not fixed—use dried/composition-verified basis when dosing

RE chlorides (hydrates; high purity)

10025-75-9

E119092

Erbium(III) chloride hexahydrate

≥99.995% metals basis

High-purity Er salt for optical/doping and solution precursors; keep dry and correct for hydrate

RE chlorides (hydrates; analytical grade)

18618-55-8

C432245

Cerium(III) chloride heptahydrate

purum p.a., ≥98% (AT)

Water-soluble for solution precursors, catalysis/doping; hydrate water affects dosing and drying

RE chlorides (anhydrous; high purity)

10361-82-7

S119219

Samarium chloride

Anhydrous, ≥99.9% metals basis, powder

For water-sensitive systems, coordination/organometallic precursor synthesis, molten-salt/halide-route materials

RE metals (high-purity metal powder)

7440-53-1

E434808

Europium

≥99.9% metals basis, powder, max particle size 250 μm

Eu metal for alloying/reduction/intermetallic studies; powder is highly reactive—store/handle under inert atmosphere

RE metals (high-purity metal powder)

7440-60-0

H434765

Holmium

≥99.9% metals basis, powder, 5 g, ≤500 μm

Ho metal for alloys, magnetic/spectroscopic studies; powder oxidizes easily—use inert handling or rapid operation

RE metals (high-purity metal powder)

7439-94-3

L434755

Lutetium

≥99.9% metals basis, powder, ≤500 μm, 1 g

Lu metal for alloying, target/evaporation feedstock, metal-state reactions; powder requires oxidation control and dust safety

RE metals (high-purity metal powder)

7440-64-4

Y476602

Ytterbium

≥99.9% metals basis, powder, ≤500 μm, 10 g

Reactive Yb metal for reduction/alloying/organometallic studies; keep sealed, dry, oxygen-free

RE metals (high-purity metal powder)

7440-65-5

Y108777

Yttrium metal

≥99.9% metals basis, powder

Used for alloy additions, target feedstock, reductant/deoxidation studies; powder improves mixing/reactivity

RE metals (high-purity metal powder)

7440-10-0

P106105

Praseodymium metal

≥99.9% metals basis, powder

For alloying, magnetic materials, metal-state reactions; control oxidation and dust hazards

RE metals (ingot, oil-sealed)

7440-00-8

N118646

Neodymium ingot

≥99.9% metals basis, ingot (in mineral oil)

Oil sealing reduces oxidation for alloying/magnet studies; degrease before use and account for surface oxide

RE metals (chips/granules)

7440-54-2

G434695

Gadolinium

≥99.9% metals basis, chips

Chips facilitate charging for melting/alloying; used in magnetic/neutron-absorption materials (oxidation control needed)

RE metals (powder/mesh)

7440-19-9

S106107

Samarium powder

≥99.9% metals basis, 200 mesh

Fine powder for mixing/sintering/alloying; Sm common in permanent magnets and alloys—oxidation control required

RE metals (high purity, REO-basis)

7429-91-6

D107056

Dysprosium metal

≥99.9% metals basis (REO)

Dy for high-temperature magnets/alloys/magnetic tuning; “REO basis” is an oxide-equivalent reporting convention, not total impurity content

RE metals (high purity powder, REO-basis)

7440-30-4

T112802

Thulium powder

≥99.9% metals basis (REO)

Tm for alloys, metal-state reactions, target/evaporation feedstock; strict moisture/oxygen control required

RE metals (high-purity metal)

7440-20-2

S107379

Scandium metal

≥99.9% metals basis

Sc for alloying (Al alloys), targets/evaporation feedstock, metal-state reactions; oxidizes readily—store sealed/inert

RE metals (high-purity metal)

7439-91-0

L105396

Lanthanum metal

≥99.9% metals basis

La for alloying, hydrogen storage, catalytic metal components; surface oxidizes easily—care in cutting/melting

RE metals (high-purity metal powder)

7440-27-9

T110937

Terbium powder

≥99.9% metals basis

Tb metal for alloys and magneto-optical/magnetic studies; powder is reactive—oxidation control needed

RE metals (ingot/lumps)

7440-45-1

C108772

Cerium metal

≥99.5% metals basis, ingot, 1–10 mm

1–10 mm lumps are easy for charging/melting/alloying; Ce used in oxygen-storage/reductive studies and alloys (surface oxidizes easily)

RE metals (ingot/lump)

7440-52-0

E119314

Erbium metal

Ingot, 99.9% metals basis

For alloying, magnetic/hydride studies, evaporation/sputtering target feedstock, or metal-state reactions (watch surface oxidation)

RE standard solutions (elemental analysis/calibration)

7440-65-5

Y684766

Yttrium standard solution

1000 μg/mL in 10% HNO

Common internal standard/calibration element; for ICP-OES/ICP-MS calibration, QC, and matrix matching

RE standard solutions (elemental analysis/calibration)

7440-54-2

G117326

Gadolinium standard solution

1000 μg/mL in 1.0 mol/L HNO

For elemental quantification, QC, drift monitoring; nitric matrix supports digestion-matrix matching

RE standard solutions (elemental analysis/calibration)

7429-91-6

D117330

Dysprosium standard solution

1000 μg/mL in 1.0 mol/L nitric acid

For Dy calibration/QC/method validation; nitric matrix aligns with nitric digestion systems

RE standard solutions (elemental analysis/calibration)

7440-53-1

E118416

Europium standard solution

1000 μg/mL in 10% HCl

For Eu calibration/QC; often used for quantitative work on luminescent-material solutions and method development

RE standard solutions (elemental analysis/calibration)

7440-60-0

H117331

Holmium standard solution

Analytical standard, 1000 μg/mL in 1.0 mol/L HNO

For calibration curves, QC preparation, method confirmation; acid matrix stabilizes ions and suppresses hydrolysis

RE standard solutions (elemental analysis/calibration)

7439-94-3

L117339

Lutetium standard solution

Analytical standard, 1000 μg/mL in 1.0 mol/L HNO

For ICP-OES/ICP-MS/AAS calibration, validation, spike recovery; nitric matrix suits most inorganic analyses

RE standard solutions (elemental analysis/calibration)

7439-91-0

L117317

Lanthanum standard solution

1000 μg/mL in 10% HCl

For calibration/QC/spike recovery; HCl matrix suits chloride matrices (note corrosion/volatility considerations)

RE standard solutions (elemental analysis/calibration)

7440-10-0

P117320

Praseodymium standard solution

1000 μg/mL in 1.0 mol/L HNO

For ICP/AAS calibration and validation; nitric systems are typically stable

RE standard solutions (elemental analysis/calibration)

7440-45-1

C117319

Cerium standard solution

1000 μg/mL in 10% HNO

For ICP/AAS calibration/QC; 10% HNO stabilizes ions and suppresses hydrolysis

RE standard solutions (elemental analysis/calibration)

7440-00-8

N117323

Neodymium standard solution

1000 μg/mL in 10% HCl

For Nd quantification/spike recovery/QC; HCl matrix fits certain methods (ensure matrix consistency)

RE standard solutions (elemental analysis/calibration)

7440-20-2

S115452

Scandium standard solution

1000 μg/mL in 10% HCl

For Sc calibration/QC; convenient when matching chloride matrices

RE standard solutions (elemental analysis/calibration)

7440-19-9

S117324

Samarium standard solution

1000 μg/mL in 10% HCl

For Sm calibration/QC/method validation; HCl matrix supports certain matrix-matching needs

RE standard solutions (elemental analysis/calibration)

7440-64-4

Y117338

Ytterbium standard solution

1000 μg/mL in 10% HCl

HCl matrix suits some methods or sample matrices; for ICP/AAS calibration and validation

RE standard solutions (elemental analysis/calibration)

7440-27-9

T117328

Terbium standard solution

1000 μg/mL in 1.0 mol/L HNO

For Tb quantification, calibration/QC; good match for nitric digestion matrices

RE standard solutions (elemental analysis/calibration)

7440-30-4

T117335

Thulium standard solution

1000 μg/mL

Often used for calibration/QC; if acid matrix is not specified, confirm matrix matching with the sample acid system before use

RE oxide dispersions (nano/water dispersion)

12061-16-4

E431579

Erbium(III) oxide, dispersion

Nanoparticles, dispersion, <100 nm (BET), 5 wt% in HO

Water-dispersed nano oxide for uniform introduction in coatings/composites/catalysis/optical studies; reduces powder agglomeration steps

RE oxide dispersions (nano)

12060-58-1

S431576

Samarium(III) oxide dispersion

Nanoparticles, <100 nm (BET)

Suitable for “uniform incorporation/loading” in sol-gel, composites, catalysis, and luminescence studies


Categories: Technical articles
Explore topics: Rare Earth Elements

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

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Cite this article

Aladdin Scientific. "What Are Rare Earths? Material Logic of 17 Elements, an Application Map, and a Quick Guide to Aladdin Reagent Selection (Oxides/Salts/Metals/Standard Solutions/Dispersions)" Aladdin Knowledge Base, updated 28 dic 2025. https://www.aladdinsci.com/us_es/faqs/what-are-rare-earths-en.html
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