Decoding the “Symbol Language” of Molecular Sieves: Pore-Size Units, 3A/4A/5A/13X, ZSM/SAPO/MCM, and IZA Framework Codes—A One-Stop Selection Guide (with an Aladdin Product Table)

Basic Concepts of Molecular Sieves

Molecular sieves are a class of materials named for their function—they possess molecular-scale pores that enable selective adsorption and diffusion. This category includes microporous materials (< 2 nm) as well as ordered mesoporous materials (2–50 nm), which are often referred to in the literature as “mesoporous molecular sieves.” They can act like a “molecular gatekeeper”: small molecules can enter, while larger molecules are excluded, leading to selective adsorption and separation.

"Molecular sieves" is therefore a functional/material category encompassing multiple material systems. Among them, the most important and widely used class is crystalline microporous materials—especially zeolites. Zeolites can be regarded as the most representative molecular-sieve family: they feature regular microporous frameworks, ion-exchange capability, and reversible dehydration, and are widely used in adsorption and catalysis.

First, Clarify This: These Symbols Actually Convey Four Types of Information

1. Size units: Å, nm (how large is the pore opening/pore size?)

2. Commercial grades: 3A/4A/5A/13X (“nominal pore opening + A/X-type zeolite system”)

3. Material family abbreviations: ZSM, SAPO, TS-1, MCM, SBA, KIT (which family/type of material; typical structural features)

4. IZA three-letter framework codes: LTA/FAU/MFI/BEA… (describe topology only; not the same as a specific chemical composition or a commercial product name)

1) What Does Å Mean? How Do You Convert It to nm?

(1) Å (ångström) is a length unit commonly used in crystallography and pore-size contexts:

1 Å = 10⁻¹⁰ m = 0.1 nm (therefore, 1 nm = 10 Å).

(2) In the molecular-sieve context, pore openings of ~3–10 Å are at the “molecular gatekeeping” scale; whereas 2–50 nm is already the typical scale of mesoporous materials, more oriented toward diffusion and loading of larger molecules.

2) 3A/4A/5A/13X: What Do the Number + “A/X” Actually Mean?

(1) “A” is not just the letter A:

1. 3A ≈ 3 Å, 4A ≈ 4 Å, 5A ≈ 5 Å, 13X ≈ 10 Å (“13X” is a historical commercial grade; its nominal pore opening is often remembered as ~10 Å.)
2. In 3A/4A/5A, the number denotes the nominal pore opening (Å). These materials are typically based on A-type zeolite (LTA framework), and the effective pore opening is tuned by exchangeable cations (Na⁺/K⁺/Ca²⁺, etc.).
3. Note: For 13X (NaX, FAU topology), the “10 Å” is often an effective/nominal pore-opening value used for engineering selection. In contrast, according to IZA geometric descriptions, the free diameter of the 12-membered-ring channel in FAU is often listed as approximately 7.4 × 7.4 Å. These two values come from different definitions (engineering-effective adsorption scale vs. structural free diameter) and are not contradictory.

(2) More importantly, the core idea is: “same framework + different exchangeable cations.”

• The most common 3A/4A/5A used in industry and laboratories are essentially all derived from the LTA (A-type) framework, with ion exchange used to make the “gate” smaller or larger. 13X commonly corresponds to the FAU (X-type) framework.

Common Grades Overview

Common grade	Common framework (IZA code)	Typical cation form (why the pore changes)	Nominal pore opening	Most common research-use keywords
3A	LTA	K⁺ exchange → “smaller gate”	~3 Å	Dehydration (more strongly “excludes” slightly larger molecules; often for solvent drying)
4A	LTA	Na⁺ form	~4 Å	General dehydration; moisture control in packaging; water removal from gases/solvents
5A	LTA	Ca²⁺ exchange → “larger gate”	~5 Å	Shape-selective separation; hydrocarbon separations; certain gas purification
13X	FAU	NaX (X-type) system	~10 Å	Gas purification (H₂O/CO₂, etc.); air-separation pretreatment, etc.

3) ZSM-5, β, SAPO, TS-1, MCM-41, SBA-15, KIT-6: What Do These Abbreviations Mean?

1. Microporous zeolites / zeolite-type materials (Å-scale pore openings; often used for catalysis and selective adsorption)

Name / format	Abbreviation / name origin	IZA framework code	Key structural information	Typical research use: what problem it solves
ZSM-5	ZSM = Zeolite Socony Mobil (series name); “-5” is an index	MFI	10-membered-ring (10MR) openings; two intersecting channel systems; a representative “medium-pore zeolite”	Shape-selective catalysis (aromatization, alkylation, MTH/MTP, etc.); adsorption/diffusion sieving
β (Beta) zeolite	“Beta/β” is a conventional name (commercial/literature)	BEA	12MR 3D channel system; a representative “large-pore zeolite”	Easier access for larger molecules; solid-acid catalysis; support and acidic framework for hydroisomerization, etc.
SAPO-11	SAPO = silicoaluminophosphate molecular sieve	AEL	10MR, 1D channels (straight-through along one direction)	Isomerization/cracking scenarios requiring “linear channels + acid sites”
SAPO-34	SAPO series index	CHA	8MR openings; cage-like structure; 3D transport	Small-molecule selective reactions such as MTO/MTP (methanol-to-olefins/propylene)
TS-1	TS-1 = Titanium Silicalite-1 (“silicalite” with framework Ti)	MFI	MFI topology + Ti incorporated into framework sites; a classic microporous catalyst dedicated to oxidation	Mild H₂O₂-based selective oxidation (epoxidation, hydroxylation, ammoximation, etc.)

2. Ordered mesoporous materials (nm-scale channels; better for diffusion/loading; catalyst supports)

Name / format	Abbreviation / name origin	Channel size scale	Key structural information	Typical research use: what problem it solves
MCM-41	MCM = Mobil Composition of Matter (Mobil R&D series)	Typically 2–10 nm (tunable)	1D hexagonally ordered cylindrical pores; high surface area	Loading/adsorption of larger molecules; catalyst support; drug delivery and surface functionalization
SBA-15	SBA = Santa Barbara Amorphous (UCSB naming system)	Commonly ~5–15 nm (tunable)	Hexagonally ordered mesopores; thicker walls and better stability; easy surface modification	Smoother mass transfer for larger molecules; very common “general-purpose mesoporous support/template”
KIT-6	Literature-named “KIT-6” series (often KIT-6 mesoporous silica)	Commonly ~4–12 nm (tunable)	3D cubic Ia3d, bicontinuous interpenetrating network; more “three-dimensional” transport	For loading/diffusion requiring 3D connectivity: e.g., metal nanoparticle dispersion; hydrogenation/oxidation supports

4) What Do the Three-Letter Codes LTA/FAU/MFI/BEA… Actually Represent?

1. They Are Called Framework Type Codes (Framework topology codes)

• Maintained by the IZA Structure Commission, this is a core “structural topology labeling system” in the zeolite/molecular-sieve field.
• These codes describe framework topology (connectivity) only. They are not a specific commercial product, and they do not guarantee Si/Al ratio, acid strength, cation form, crystal size, etc.
• This framework-code system applies not only to traditional aluminosilicate zeolites, but also to AlPO, SAPO, and other “zeotype” crystalline microporous materials—as long as the framework topology is the same, the same three-letter code may be used.

2. A “translation” of common framework-code correspondences

Framework code	Names you often see (examples)	One-sentence memory hook
LTA	3A/4A/5A (A-type system)	“A-type framework”; pore opening is strongly influenced by cations (that’s where 3/4/5 Å come from)
FAU	13X (X-type system), X/Y family	Larger cavities; commonly used for gas purification/adsorptive separation
MFI	ZSM-5, Silicalite-1, TS-1	Medium-pore, intersecting channels; a flagship framework for shape-selective catalysis
BEA	β (Beta) zeolite	Large-pore 3D channels; suitable for “larger” molecules to access
CHA	SAPO-34 / CHA family	Small-pore cage-like structure; common in MTO/MTP
AEL	SAPO-11 / AlPO-11	10MR 1D channels (“a one-way highway”)
MWW	MCM-22	Two channel systems; characteristic “intralayer/interlayer” features
TON / MEL / FER	ZSM-22 / ZSM-11 / ZSM-35, etc.	Different zeolite topologies with different channel dimensionality and openings; directly affect diffusion and selectivity

5) What “Key Structural Information” Should You Look At? (Missing These Often Leads to Wrong Choices)

When you encounter a molecular-sieve entry, prioritize these six hard facts that won’t mislead you:

1. Pore scale: Å-scale (microporous) or nm-scale (mesoporous)
2. Channel dimensionality: 1D / 2D / 3D (directly affects diffusion and susceptibility to pore blocking)
3. Ring size at the pore opening: 8MR / 10MR / 12MR (bigger generally admits larger molecules, but changes selectivity)
4. Framework composition: aluminosilicate (acidity), SAPO (differences in acidity and hydrothermal stability), Ti-containing (oxidation activity), etc.
5. Cation/form: Na⁺/K⁺/Ca²⁺/H⁺… (affects effective pore opening, acidity, and adsorption selectivity)
6. Morphology/particle size/spec: powder/spheres/extrudates, mesh, mm pellets (affects packing, mass transfer, pressure drop, regeneration)

Why Zeolites Are Often Called “Molecular Sieves”

Because zeolites have highly regular pore sizes and can “admit or exclude” molecules, they are often treated as the canonical representatives of “molecular sieve materials.” In many industrial and laboratory contexts, “molecular sieves” is almost synonymous with zeolite desiccants such as 3A/4A/5A/13X.

A Practical Rule of Thumb to Distinguish Them

1. If you see 3A/4A/5A/13X or LTA/FAU/MFI/BEA (framework codes) → it is essentially a zeolite / zeolite-type molecular sieve (crystalline microporous).
2. If you see SAPO, AlPO, TS-1 → they are zeolite-like molecular sieves: structurally very similar to zeolites (also crystalline microporous), but the chemical composition is not necessarily a traditional “aluminosilicate zeolite.”
3. If you see MCM-41, SBA-15, KIT-6 → they are mostly ordered mesoporous materials (mesoporous silica) with nm-scale pores. They are sometimes called “mesoporous molecular sieves,” but their sieving mechanism and application focus differ from those of microporous zeolitic molecular sieves.

Why Molecular Sieves Are So Useful: Four “Hard-Core” Advantages

1) Highly uniform pore size → size/shape selectivity

• In crystalline microporous molecular sieves, pore openings and channels are strictly defined by framework topology, forming a channel network with “nearly identical gate sizes.” As a result, whether a molecule can enter, how fast it diffuses, and whether it can react inside the pore often show strong size/shape selectivity—this is also the intuitive origin of the term “molecular sieve.”

2) Charged framework + ion exchange → tunable selectivity

• For most aluminosilicate zeolites, isomorphous substitution of Si⁴⁺ by Al³⁺ introduces negative framework charge, which must be compensated by cations inside the pores. These “pore cations” are often exchangeable, allowing researchers/engineers to tune affinity for polar molecules, adsorption selectivity, and even catalytic active-site properties through ion exchange and composition control.

Note: Pure-silica frameworks are usually closer to electrically neutral, and their ion-exchange capacity is much weaker.

3) Acid sites → solid-acid catalysis (but not all molecular sieves are strongly acidic)

• Catalysis by molecular sieves often relies on acidity. In Al-containing zeolites, when the charge-compensating cation is a proton (H⁺), classic Brønsted acid sites form (often described as bridging hydroxyls Si–OH–Al), enabling solid-acid catalysis.
• Reminder: Common desiccant grades such as 3A/4A/5A/13X are often in Na⁺/K⁺/Ca²⁺ forms; they behave more as adsorption/ion-exchange materials and are not equivalent to “strong solid-acid catalysts.”
• For SAPO/AlPO systems, the origin of acidity and site chemistry (e.g., negative charge/acid sites introduced by Si substitution) is not strictly identical to that of aluminosilicate zeolites; site chemistry depends on the specific system.

4) Regenerable → suitable for cyclic use (but operate within the “bed temperature window”)

• After saturation, molecular sieves can typically be regenerated by heating with purge gas and/or applying vacuum to desorb adsorbates and restore capacity. Different sieve types have different commonly used regeneration temperature windows. For example, technical references often cite bed-temperature ranges of 3A: 175–260 °C, and 4A/5A/13X: 200–315 °C. In practice, you should also consider the adsorbate identity, heating rate, presence of polymerizable impurities, etc., and cool sufficiently before returning to service.
• Note: These are bed/process regeneration conventions; laboratory activation should follow the technical documentation of the specific product.

Molecular Sieve Classification Map

1. By Pore Structure / Framework (Determines How Large a Molecule Can Be Accommodated)

The classic IUPAC pore-size classification is: micropores ≤ 2 nm; mesopores 2–50 nm; macropores > 50 nm.

Category	Key structural features	Representative families / entries
Microporous adsorption-type molecular sieves / zeolites (≤ 2 nm; Å-scale pore openings)	Uniform pore openings; mainly for adsorption/drying/purification; common commercial grades such as 3A/4A/5A/13X/10X	3A/4A/5A/13X/10X (including mm-sized desiccant particles, beads/pellets, and GC/LC mesh grades)
Microporous catalytic zeolites (≤ 2 nm)	Also microporous, but with emphasis on acidity and shape selectivity; framework topology and Si/Al ratio (etc.) influence catalytic pathways	ZSM-5/ZSM-11/ZSM-22/ZSM-23/ZSM-35, β (Beta), MCM-22, SAPO-11/SAPO-34
Microporous “zeotype” functional molecular sieves (≤ 2 nm)	Still microporous topology, but designed for specific catalysis via heteroatom sites (commonly selective oxidation)	TS-1 / titanium silicalite TS-1 (typically H₂O₂-based selective oxidation; industrial application reports exist)
Ordered mesoporous materials (2–50 nm; nm-scale channels)	Larger “nano-channels” suited to diffusion/loading/confinement of large molecules; common MCM/SBA/KIT families	MCM-41, MCM-48, SBA-3, SBA-15 (including SBA-15-4.2), SBA-16, KIT-6
Functionalized / doped mesoporous materials (2–50 nm)	Introducing Al/Fe, etc. into a mesoporous framework; mainly “support site engineering / adsorption–catalysis interface tuning”	Al-SBA-15, Fe-SBA-15

2. By Function (Determines What Problem It Solves)

Functional class	Typical problems addressed	Corresponding families (examples)	Most critical selection keywords
Adsorptive drying / purification	Dehydration of solvents/gases; gas purification (e.g., water removal; in some systems, CO₂ can also be removed)	3A/4A/13X/10X (desiccant particles, beads/pellets, etc.)	Pore opening size; form factor (mm particles vs beads/pellets); regeneration method
Adsorptive separation (shape selectivity)	Separation of linear/branched/cyclic species by size/shape	5A (a classic for shape-selective separations)	Pore-opening match; bed pressure drop; regeneration frequency
Chromatography / analytical packing	GC/LC adsorbents/packings (greater emphasis on particle size and cleanliness)	UltraPureChrom™ / for GC/LC / chromatography-column dedicated / mesh series (different mesh sizes of 3A/4A/5A/13X)	Mesh size; background/impurities; column efficiency vs backpressure
Solid-acid / shape-selective catalysis	Using pore topology + acidity to control pathways and selectivity	ZSM family, β, MCM-22, SAPO-11/34	Framework type; Si/Al (or acidity indicators); channel dimensionality (1D/3D)
Selective oxidation catalysis	High-selectivity oxidation under mild conditions (often associated with H₂O₂ systems)	TS-1 / titanium silicalite TS-1 (industrial application reports exist)	Site type (Ti, etc.); hydrophobicity / water tolerance; diffusion limitations
Support / confinement platform	Loading metals/acids/bases/enzymes; enabling large molecules to “get in and get out”	MCM-41/MCM-48, SBA-15/SBA-16, KIT-6; and Al-/Fe-SBA-15	Pore size (nm); surface area/pore volume; pore connectivity (3D vs 2D)

Where Are Molecular Sieves Used in Research—and What Problems Do They Solve?

Scenario A: “Dehydration-driven equilibrium shifting” in organic synthesis

• Many reactions—such as condensations, imine/enamine formation, and acetal/ketal formation—are limited by water as a byproduct. Molecular sieves drive the equilibrium toward products by adsorbing water.
• Note: Molecular sieves may also non-selectively adsorb certain small-molecule substrates/solvents (e.g., some alcohols and amines), or interact with acidic species via ion exchange or surface effects. Small-scale trials and blank controls are recommended.

Scenario B: Solvent and gas-line drying (especially for water-sensitive systems)

• In glovebox/inert-atmosphere experiments and in water-sensitive catalytic or reagent systems, molecular sieves are widely used for drying solvents and purifying gas lines, with the advantage of high capacity and regenerability.
• Key points: fully activate/regenerate before use, and watch for carryover of fine powders and non-target adsorption of additives/substrates.

Scenario C: Catalysis research (shape selectivity + site-engineering controls)

• Researchers often compare different frameworks (e.g., ZSM, β, SAPO) to study how topology and pore openings affect selectivity, and tune acidity and hydrophobicity via Si/Al adjustment, ion exchange, or heteroatom incorporation to build structure–performance relationships.
• Beyond framework and Si/Al, crystal size and diffusion limitations (e.g., whether hierarchical pores exist) can also strongly affect apparent results.

Scenario D: Mesoporous materials as “large-molecule channels” and supports

• When substrates/polymers/enzymes or nanoparticles to be loaded are large and microporous zeolites become diffusion-limited, ordered mesoporous materials such as SBA-15, MCM-41, and KIT-6 are often used as supports/confinement platforms. Their core advantage is “larger channels and smoother mass transfer.”
• They are better at solving diffusion/loading problems than the Å-scale “gatekeeping sieving” typical of microporous zeolites.

Scenario E: Analytical and chromatographic sample preparation

Molecular sieves are also commonly used for drying/purification in GC/LC or gas-line systems and for sample pretreatment (corresponding to “chromatography-grade mesh” and “analysis-specific” product forms).

How to Choose: A Practical “Decision Tree”

Step 1: What exactly are you trying to remove/separate?

1. Target is water (or small molecules such as CO₂, H₂S, thiols, etc.) → typically choose adsorptive drying/purification types (3A/4A/13X, etc.).
2. Target is linear vs branched separation → focus on 5A, which has strong shape-selective separation capability.
3. Target is catalysis → decide whether you need acidity (ZSM/β/SAPO) or selective oxidation (TS-1).
4. Target is diffusion/loading of large molecules → go directly to mesoporous materials (MCM/SBA/KIT).

Step 2: Match the “pore opening” to molecular size

1. Principle: the pore opening must be large enough for your target to enter, but small enough to exclude molecules you do not want inside.
2. In practice, preliminary screening often uses data such as critical diameter or kinetic diameter (many technical references provide tables of critical diameters for common molecules).

Step 3: Then consider form factor and grade

1. mm particles / spherical beads / pellets: suitable for packing, cyclic regeneration, and controllable pressure drop
2. beads + mesh: commonly used in fixed beds or for specific packing requirements
3. Chromatography grade (GC/LC, specified mesh): emphasizes particle-size distribution and cleanliness (trade-off between column efficiency and backpressure)

Step 4: Don’t ignore hydrophobicity/acidity

1. Structural factors such as Si/Al ratio can affect zeolite hydrophobicity, stability, and catalytic/adsorption behavior; high-silica materials tend to be more hydrophobic and have a lower density of acid sites (as a general trend).

Usage Notes

1. Activate/regenerate before use: Molecular sieves often contain adsorbed water upon shipment or after exposure to air. Typical activation involves heating with purge gas and/or vacuum. Regeneration windows vary by type (commonly cited bed-temperature ranges: 3A: 175–260 °C; 4A/5A/13X: 200–315 °C). Slow heating is recommended, and after regeneration the material should be cooled to near the intended use temperature.
2. Be aware they may “remove things you didn’t mean to remove”: Besides water, molecular sieves may adsorb small molecules such as alcohols, CO₂, and H₂S—sometimes beneficial, sometimes altering composition (especially in trace analysis or kinetic studies).
3. Watch for side reactions from solid-acid or surface sites: In some systems, isomerization, condensation, or adsorption-induced selectivity changes may occur—especially with acidic zeolites or materials containing active sites. Blank controls are strongly recommended.
4. Do not mix up the logic of mesoporous vs microporous materials: Mesoporous materials solve diffusion and loading problems, while microporous materials solve sieving and strong adsorption. Their pore-size scales differ by roughly an order of magnitude.

Frequently Asked Questions (FAQ)

Q1: How can I quickly choose between 3A/4A/5A/13X?

A: Choose based on “pore opening + target task.”

• 3A/4A are commonly used for dehydration (3A has a smaller pore opening; 4A is more general-purpose).
• 5A is strong in linear/branched separation and certain natural-gas purification applications.
• 13X has a larger pore opening and is often used for gas drying and air-separation pretreatment (water removal + CO₂ removal).

Q2: Are molecular sieves the same as zeolites?

A: Molecular sieves are a functional term for porous materials that sieve at the molecular scale. Zeolites are the most important subfamily (e.g., crystalline microporous aluminosilicates).

Q3: Why do some people write LTA/FAU/MFI, while others write 4A/13X/ZSM-5?

A: LTA/FAU/MFI are framework topology codes (describing the framework structure). 4A/13X/ZSM-5 are more commonly used engineering-grade names/material names, often tied to specific cations/compositions/forms. A framework code is not equivalent to a specific material.

Q4: Can molecular sieves be reused?

A: Yes. They are designed for regeneration and cyclic use: adsorbates can be removed to restore capacity by heating/purging, etc., but you must follow the appropriate regeneration temperature range and operating window for the specific type.

Q5: Are mesoporous materials (SBA-15/MCM-41) still considered “molecular sieves”?

A: Many papers call them “mesoporous molecular sieves/mesoporous sieves.” However, it should be made clear that they mainly provide 2–50 nm mesoporous channels, with mechanisms focused on diffusion and serving as loading/support platforms, rather than the Å-scale shape-selective sieving typical of zeolitic micropores.

Aladdin Master Product Table of Molecular Sieves and Mesoporous Materials

(Tiered classification by pore structure × application scenario: drying / chromatography / analysis / catalysis / supports)

Category	Aladdin Cat. No.	Product Name	CAS No.	Specification / Purity	Product Features or Applications
Microporous zeolitic molecular sieve | X-type | 10X | desiccant/adsorbent grade | particles 3–5 mm	M116951	10X Molecular Sieve	-	Desiccant grade, 3–5 mm	General adsorption/drying; a common fixed-bed packing size; used for gas/solvent dehydration and adsorption purification.
Microporous zeolitic molecular sieve | X-type | 13X | desiccant/adsorbent grade | particles 2–3 mm	M105940	13X Molecular Sieve	63231-69-6	2–3 mm, desiccant grade	13X for drying/adsorption; suitable for small fixed beds/drying columns.
Microporous zeolitic molecular sieve | X-type | 13X | desiccant/adsorbent grade | particles 3–5 mm	M140030	13X Molecular Sieve	63231-69-6	3–5 mm, desiccant grade	Common packing size for 13X; convenient for regenerative cyclic use.
Microporous zeolitic molecular sieve | X-type | 13X | desiccant/adsorbent grade | particles 4–6 mm	M140031	13X Molecular Sieve	63231-69-6	4–6 mm, desiccant grade	Coarser particles, more oriented to low pressure drop in fixed beds/drying towers.
Microporous zeolitic molecular sieve | X-type | 13X | desiccant/adsorbent grade | spherical 2–3 mm	M105942	13X Molecular Sieve	63231-69-6	2–3 mm, spherical	Spherical packing for uniform bed and good flowability; used for fixed-bed dehydration/adsorptive separation.
Microporous zeolitic molecular sieve | X-type | 13X | desiccant/adsorbent grade | spherical 3–5 mm	M105941	13X Molecular Sieve	63231-69-6	3–5 mm, beads	3–5 mm spheres balance pressure drop and mass transfer; suitable for fixed beds.
Microporous zeolitic molecular sieve | X-type | 13X | chromatography grade (GC/LC) | 40–60 mesh	M105939	13X Molecular Sieve	63231-69-6	40–60 mesh	Chromatography-grade adsorbent/packing; coarser particles typically give lower backpressure.
Microporous zeolitic molecular sieve | X-type | 13X | chromatography grade (GC/LC) | 60–80 mesh	M105937	13X Molecular Sieve	63231-69-6	60–80 mesh	Common “balanced” chromatography grade; balances column efficiency and backpressure.
Microporous zeolitic molecular sieve | X-type | 13X | chromatography grade (GC/LC) | 80–100 mesh	M105938	13X Molecular Sieve	63231-69-6	80–100 mesh	Finer particles often improve efficiency/resolution, but increase backpressure.
Microporous zeolitic molecular sieve | A-type | 3A | desiccant/adsorbent grade | pellets 3–5 mm	M100323	3 Å Molecular Sieve	308080-99-1	Pellets, 3–5 mm	Strongly selective dehydration at 3Å; suitable for fixed beds/drying columns.
Microporous zeolitic molecular sieve | A-type | 3A | desiccant/adsorbent grade | particles 3–5 mm	M100322	3 Å Molecular Sieve	308080-99-1	3–5 mm, desiccant grade	Standard desiccant particle size; for deep dehydration of solvents/gases.
Microporous zeolitic molecular sieve | A-type | 3A | desiccant/adsorbent grade | particles 2–3 mm	M100324	Molecular Sieve, 3 Å	308080-99-1	Particles, 2–3 mm	Smaller particles give faster mass transfer but higher pressure drop; suitable for small columns/small fixed beds.
Microporous zeolitic molecular sieve | A-type | 3A | desiccant/adsorbent grade | extrudates (strip)	M137843	Molecular Sieve, 3 Å	308080-99-1	Extrudates (strip)	Common engineering packing form; used in drying towers/fixed-bed dehydration and adsorption.
Microporous zeolitic molecular sieve | A-type | 3A | desiccant/adsorbent grade | extrudates 1/8”	M1272960	Molecular Sieve 3A	308080-99-1	1/8” extrudates	Typical fixed-bed packing specification; suitable for continuous dehydration/adsorption.
Microporous zeolitic molecular sieve | A-type | 3A | desiccant/adsorbent grade | particles 4–6 mm	M140026	Molecular Sieve 3A	308080-99-1	4–6 mm, desiccant grade	Coarser particles favor lower pressure drop; suitable for higher-throughput fixed beds.
Microporous zeolitic molecular sieve | A-type | 3A | desiccant/adsorbent grade | particles 2–3 mm	M140027	Molecular Sieve 3A	308080-99-1	2–3 mm, desiccant grade	Common lab packing size; a balance between dehydration efficiency and pressure drop.
Microporous zeolitic molecular sieve | A-type | 3A | powder (materials/mechanism research)	M1372199	Molecular Sieve, 3 Å	308080-99-1	Powder	Powder for adsorption mechanism/material studies or as an additive; not recommended for direct fixed-bed packing.
Microporous zeolitic molecular sieve | A-type | 3A | general catalysis/adsorption | spherical particles	M598389	3 Å Molecular Sieve	308080-99-1	Spherical particles; use: catalyst	Used as a water-control/adsorption component in catalytic systems or adsorption–catalysis coupled materials; spherical form aids packing.
Microporous zeolitic molecular sieve | A-type | 3A | analysis-specific (elemental analysis) | Φ 1–2.5 mm	M141467	Molecular Sieve, 3A	308080-99-1	For elemental analysis, Φ: 1–2.5 mm	For pretreatment such as gas-line purification/dehydration in analytical systems; suitable for small tubing.
Microporous zeolitic molecular sieve | A-type | 3A | chromatography grade (GC/LC) | 20–40 mesh	M100318	3Å; Molecular Sieve	308080-99-1	20–40 mesh, for GC/LC columns	Column packing / adsorption purification; coarser mesh usually gives lower backpressure.
Microporous zeolitic molecular sieve | A-type | 3A | chromatography grade (GC/LC) | 40–60 mesh	M100319	3 Å Molecular Sieve	308080-99-1	40–60 mesh, for GC/LC columns	Common particle-size range for column packing.
Microporous zeolitic molecular sieve | A-type | 3A | chromatography grade (GC/LC) | 60–80 mesh	M100320	3 Å Molecular Sieve	308080-99-1	60–80 mesh, for GC/LC columns	Balanced mesh: efficiency vs backpressure.
Microporous zeolitic molecular sieve | A-type | 3A | chromatography grade (GC/LC) | 80–100 mesh	M100321	3 Å Molecular Sieve	308080-99-1	80–100 mesh, for GC/LC columns	Finer mesh; often improves efficiency but increases backpressure.
Microporous zeolitic molecular sieve | A-type | 3A | chromatography grade (GC/LC) | ≥100 mesh	M299538	Molecular Sieve, 3Å	308080-99-1	≥100 mesh, for GC/LC columns	Very fine chromatography packing; for high-efficiency adsorption separation/purification (note backpressure).
Microporous zeolitic molecular sieve | A-type | 4A | desiccant/adsorbent grade | particles 1–1.6 mm	M139984	Molecular Sieve, 4 Å	-	1–1.6 mm, desiccant grade	Smaller particles improve contact/mass transfer but raise pressure drop; suitable for small columns.
Microporous zeolitic molecular sieve | A-type | 4A | desiccant/adsorbent grade | particles 3–5 mm	M165304	Molecular Sieve, 4 Å	-	3–5 mm, desiccant grade	General-purpose desiccant size; suitable for fixed beds/drying columns.
Microporous zeolitic molecular sieve | A-type | 4A | desiccant/adsorbent grade | beads 1–4 mesh	M406640	Molecular Sieve, 4 Å	70955-01-0	Beads, 1–4 mesh	Coarse beads with low pressure drop; oriented to drying towers/high-throughput fixed beds.
Microporous zeolitic molecular sieve | A-type | 4A | desiccant/adsorbent grade | beads 4–8 mesh	M103748	Molecular Sieve, 4 Å	-	Beads, 4–8 mesh	Medium beads: balance pressure drop and mass transfer; general fixed-bed packing.
Microporous zeolitic molecular sieve | A-type | 4A | desiccant/adsorbent grade | beads 8–12 mesh	M103749	Molecular Sieve, 4 Å	-	Beads, 8–12 mesh	Finer beads: better mass transfer but higher pressure drop.
Microporous zeolitic molecular sieve | A-type | 4A | desiccant/adsorbent grade | particles 2–3 mm	M103747	Molecular Sieve 4A	-	2–3 mm, desiccant grade	Common lab packing size; for solvent/gas dehydration.
Microporous zeolitic molecular sieve | A-type | 4A | chromatography grade (GC/LC) | 20–40 mesh	M103739	4A Molecular Sieve	-	UltraPureChrom™, for GC/LC, 20–40 mesh	Coarser chromatography grade with low backpressure; suitable for low-pressure packing/purification.
Microporous zeolitic molecular sieve | A-type | 4A | chromatography grade (GC/LC) | 40–61 mesh	M103740	4A Molecular Sieve	-	UltraPureChrom™, for GC/LC, 40–61 mesh	Medium particle-size chromatography packing.
Microporous zeolitic molecular sieve | A-type | 4A | chromatography grade (GC/LC) | 60–80 mesh	M103741	4A Molecular Sieve	-	UltraPureChrom™, for GC/LC, 60–80 mesh	Common balanced grade; efficiency vs backpressure.
Microporous zeolitic molecular sieve | A-type | 4A | chromatography grade (GC/LC) | 80–100 mesh	M103744	4A Molecular Sieve	-	UltraPureChrom™, for GC/LC, 80–100 mesh	Finer particles; often improves efficiency but increases backpressure.
Microporous zeolitic molecular sieve | A-type | 5A | desiccant/adsorbent grade | particles 4–6 mm	M140029	Molecular Sieve, 5 Å	69912-79-4	4–6 mm, desiccant grade	Coarser particles favor low pressure drop in fixed beds/drying towers.
Microporous zeolitic molecular sieve | A-type | 5A | desiccant/adsorbent grade | particles 3–5 mm	M103773	Molecular Sieve, 5 Å	69912-79-4	3–5 mm, desiccant grade	Common packing size; for dehydration and adsorption purification.
Microporous zeolitic molecular sieve | A-type | 5A | desiccant/adsorbent grade | pellets 3–5 mm	M103774	Molecular Sieve, 5 Å	69912-79-4	Pellets, 3–5 mm	Pellets suitable for fixed-bed packing and regenerative cycling.
Microporous zeolitic molecular sieve | A-type | 5A | desiccant/adsorbent grade | pellets 2.5–3.5 mm	M103775	Molecular Sieve, 5 Å	69912-79-4	Pellets, 2.5–3.5 mm	Smaller pellets: faster mass transfer but higher pressure drop; for small fixed beds/high-efficiency drying.
Microporous zeolitic molecular sieve | A-type | 5A | desiccant/adsorbent grade | particles 2–3 mm	M140028	Molecular Sieve, 5 Å	69912-79-4	2–3 mm, desiccant grade	Smaller particles suited to small columns; manage pressure drop and attrition/fines.
Microporous zeolitic molecular sieve | A-type | 5A | chromatography grade (GC/LC) | 20–40 mesh	M103769	Molecular Sieve, 5 Å	69912-79-4	UltraPureChrom™, for GC/LC, 20–40 mesh	Coarser chromatography grade with low backpressure; suitable for low-pressure packing/guard columns/purification.
Microporous zeolitic molecular sieve | A-type | 5A | chromatography grade (GC/LC) | 40–60 mesh	M103770	Molecular Sieve, 5 Å	69912-79-4	UltraPureChrom™, for GC/LC, 40–60 mesh	Common particle-size range for chromatography packing.
Microporous zeolitic molecular sieve | A-type | 5A | chromatography grade (GC/LC) | 60–80 mesh	M103771	Molecular Sieve, 5 Å	69912-79-4	UltraPureChrom™, for GC/LC, 60–80 mesh	Balanced grade: efficiency/backpressure trade-off.
Microporous zeolitic molecular sieve | A-type | 5A | chromatography grade (GC/LC) | 80–100 mesh	M103772	Molecular Sieve, 5 Å	69912-79-4	UltraPureChrom™, for GC/LC, 80–100 mesh	Finer particles; often improve efficiency but increase backpressure.
Microporous zeolite for catalysis | β (Beta)	M196617	Beta Molecular Sieve (β)	-	Pore size: 0.55–0.7 nm	Beta zeolite: a typical material for solid-acid catalysis/shape-selectivity studies; pore-size data help assess diffusion and selectivity.
Microporous zeolite for catalysis | MCM-22 (MWW family)	M196705	MCM-22 Molecular Sieve	-	Pore size (nm): 0.55–1.0; Si/Al ratio: 30	MCM-22: relevant to acid catalysis/shape selectivity; Si/Al correlates with acidity and hydrophobicity.
Microporous zeolite for catalysis | ZSM-5	M196697	ZSM-5 Molecular Sieve	-	-	Classic solid-acid/shape-selective zeolite; performance depends on acid form, Si/Al ratio, crystal size, and post-treatments.
Microporous zeolite for catalysis | ZSM-11	M196709	ZSM-11 Molecular Sieve	-	Na-form; BET surface area: 160 m²/g; SiO₂/Al₂O₃ (mol): 25–30	ZSM-11: “Na-form” indicates it may need ion exchange to H-form before catalytic studies.
Microporous zeolite for catalysis | ZSM-23	M196710	ZSM-23 Molecular Sieve	-	-	Shape-selective microporous zeolite, often used in hydrocarbon-conversion mechanism/formulation comparative studies.
Microporous zeolite for catalysis | ZSM-22	M196703	ZSM-22 Molecular Sieve	-	Pore size (nm): 0.56–0.58; Si/Al ratio: 20–300	ZSM-22: shape-selective/acid catalysis; wide Si/Al range covers different acidity/hydrophobicity regimes.
Microporous zeolite for catalysis | ZSM-35	M196701	ZSM-35 Molecular Sieve	-	Pore size (nm): 0.5–0.6; Si/Al ratio: 20–90	ZSM-35: shape-selective/acid catalysis research; pore size and Si/Al used for structure–performance correlation.
Microporous molecular sieve for catalysis | SAPO-11	M196700	SAPO-11 Molecular Sieve	-	Pore size (nm): 0.6–0.7; Si/Al ratio: SiO₂/P₂O₅/Al₂O₃ = 0.5–0.8:1:1	SAPO-11: silicoaluminophosphate molecular sieve for acid catalysis/shape-selectivity; composition parameters help interpret framework and acidity trends.
Microporous molecular sieve for catalysis | SAPO-34	M196702	SAPO-34 Molecular Sieve	--	Avg. crystal size (μm): 1.5; pore size (nm): 0.4; P/Al ratio: 1	SAPO-34: small-pore molecular sieve often used for shape-selective catalysis; crystal size affects diffusion and coking behavior.
Microporous molecular sieve for catalysis | TS-1 (titanium silicalite)	M196704	TS-1 Molecular Sieve		-	TS-1: classic selective-oxidation molecular sieve (Ti sites); used in selective oxidation/epoxidation studies.
Microporous molecular sieve for catalysis | TS-1 (titanium silicalite) | with BET/pore size	T302641	Titanium Silicalite TS-1	-	Pore size: 0.56–0.58 nm; BET: 350–450 m²/g	TS-1 for selective-oxidation catalysis; BET/pore-size data help with loading and diffusion comparisons.
Ordered mesoporous material | KIT-6 (3D connectivity)	M196699	KIT-6 Molecular Sieve	-	Surface area: 780 m²/g; avg. pore size: 9.2 nm	3D-connected mesopores; suitable as support/template/adsorbent; beneficial for diffusion and dispersion/loading of large species.
Ordered mesoporous material | MCM-41 (hexagonal mesopores) | low Na / high pore volume	M196708	MCM-41 Molecular Sieve	-	Pore size: 3.5 nm; surface area >850 m²/g; pore volume ≥0.80 cm³/g; Na content ≤0.5%	Mesoporous silica support/adsorption platform; low Na helps reduce ionic impurity effects.
Ordered mesoporous material | MCM-41 (hexagonal mesopores) | all-silica / with particle size	M196707	MCM-41 Molecular Sieve	-	Pore size: 2.5 nm; particle size: 1–2 μm; surface area: 600–800 m²/g; all-silica	All-silica tends to be more inert/hydrophobic as a control support; particle size helps guide dispersion/film formation/packing choices.
Ordered mesoporous material | MCM-48 (3D connectivity)	M196706	MCM-48 Molecular Sieve	-	Reagent grade	3D mesoporous network aids diffusion; used for supports, adsorption, and templating studies.
Ordered mesoporous material | SBA-3 | all-silica / high surface area	M196712	SBA-3 Molecular Sieve	-	SiO₂/Al₂O₃ (mol): all-silica; pore size: 2.8–3.8 nm; BET ≥900 m²/g	High-surface-area mesoporous material for adsorption and supports; all-silica suitable for inert/confinement controls.
Ordered mesoporous material | SBA-15 | pore size 6–11 nm	M196613	SBA-15 Molecular Sieve	-	Pore size: 6–11 nm; surface area: 600–800 m²/g	Classic mesoporous support; suitable for diffusion/loading/adsorption of larger molecules.
Ordered mesoporous material | SBA-15 | specified pore size 4.2 nm	M196614	SBA-15-4.2 Molecular Sieve	-	Surface area: 433.8 m²/g; pore size: 4.2 nm	Specified pore size facilitates diffusion/confinement effect comparisons; support/adsorption platform.
Ordered mesoporous material | SBA-16 (3D mesopores / cage-like)	M196612	SBA-16 Molecular Sieve	-	Pore size: 2.5–4.0 nm	3D mesoporous structure favors diffusion; used for supports, adsorption, and templating studies.
Ordered mesoporous material | SBA-15-based | Al functionalization (Al-SBA-15)	M196616	Al-SBA-15 Molecular Sieve	-	Surface area >600 m²/g; pore size: 6–8 nm	Al-functionalized SBA-15 for introducing/tuning acidity or functional sites in mesoporous support research.
Ordered mesoporous material | SBA-15-based | Fe functionalization (Fe-SBA-15)	M196615	Fe-SBA-15 Molecular Sieve	-	-	Fe-functionalized SBA-15 for introducing redox active sites and building synergistic catalysis or adsorption–catalysis systems.
Microporous zeolite/molecular sieve | general synthetic zeolite (powder) | materials / adsorption–catalysis research	P103646	Synthetic Zeolite	1318-02-1	Particle size ≤10.0 μm	Synthetic zeolite powder (microporous crystalline material) for adsorption/ion exchange/catalytic mechanism studies; small particles aid dispersion and sample prep (note dust and filtration).
Ordered mesoporous material | MCM-41 (hexagonal mesopores) | mesoporous aluminosilicate / support platform	A475517	Aluminosilicate, Mesoporous Structure	1318-02-1	MCM-41 (hexagonal)	Typical hexagonally ordered mesoporous material (MCM-41), suitable for diffusion/loading of large molecules; widely used as catalyst supports, adsorbents, surface functionalization, and confined-reaction platforms.
Microporous zeolite/molecular sieve | silver ion–exchanged zeolite (Ag⁺-zeolite) | functional adsorption / antimicrobial type	S477658	Silver Ion–Exchanged Zeolite		1.2–1.6 mm	Ag⁺ exchange provides antibacterial/antimicrobial and odor/VOC adsorption functions; 1.2–1.6 mm particles are convenient for fixed-bed/packed applications (performance depends on silver loading and release conditions).

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