Magnesium Hydroxide (CAS 1309-42-8): companion and pitfall notes for Fine Chemicals
Magnesium Hydroxide (CAS 1309-42-8; InChIKey VTHJTEIRLNZDEV-UHFFFAOYSA-L) is a chemical raw material used in Industrial Chemicals, with formula H2MgO2 and molecular weight 58.32 g/mol. This page lists database-verifiable properties, what those values imply for formulation and QC, and a specification checklist for Industrial Chemicals applications.
Key takeaways
- TPSA 2 Ų and 2 H-bond donors / 2 acceptors mean a small polar surface area usually favours compatibility with non-polar resins and oils.
- Molecular weight 58.32 g/mol: 1 mol = 58.32 g. Use this for stoichiometric, neutralisation or substitution calculations — never substitute a related material by mass alone. Accurate mass 57.9905210 supports HRMS identification (add a proton for [M+H]+).
- InChIKey VTHJTEIRLNZDEV-UHFFFAOYSA-L is the reliable cross-database identifier — more dependable than a trade or common name for ruling out hydrate/anhydrous and same-name-different-substance mix-ups.
- rotatable bonds: flexible molecules often crystallise slowly and form solvates. If caking or a broad melting range appears, check polymorph and residual solvent before rejecting the assay.
Published properties of Magnesium Hydroxide (by CAS 1309-42-8)
| Property | Value |
|---|---|
| Molecular formula | H2MgO2 |
| Molecular weight | 58.32 g/mol |
| Accurate mass | 57.9905210 |
| IUPAC name | magnesium dihydroxide |
| InChIKey | VTHJTEIRLNZDEV-UHFFFAOYSA-L |
| Topological polar surface area | 2 Ų |
| H-bond donors / acceptors | 2 / 2 |
| Rotatable bonds | 0 |
| Heavy atoms | 3 |
Computed values above: PubChem CID 73981; melting/boiling points, where shown, come from the site product page.
What the numbers mean in practice
| Aspect | Evidence and actionable conclusion |
|---|---|
| Molecular polarity | TPSA 2 Ų and 2 H-bond donors / 2 acceptors mean a small polar surface area usually favours compatibility with non-polar resins and oils. |
| Dosing & analytical checks | Molecular weight 58.32 g/mol: 1 mol = 58.32 g. Use this for stoichiometric, neutralisation or substitution calculations — never substitute a related material by mass alone. Accurate mass 57.9905210 supports HRMS identification (add a proton for [M+H]+). |
| Substance identity | InChIKey VTHJTEIRLNZDEV-UHFFFAOYSA-L is the reliable cross-database identifier — more dependable than a trade or common name for ruling out hydrate/anhydrous and same-name-different-substance mix-ups. |
| Crystallisation & incoming QC | rotatable bonds: flexible molecules often crystallise slowly and form solvates. If caking or a broad melting range appears, check polymorph and residual solvent before rejecting the assay. |
Specification checklist for Industrial Chemicals use
| Check | Why it matters | How to verify |
|---|---|---|
| Batch baseline (CAS 1309-42-8) | Product-specific values to check line by line against the COA and specification; salts and hydrates differ | 分子量 58.32 g/mol; TPSA 2 Ų; InChIKey VTHJTEIRLNZDEV-UHFFFAOYSA-L |
| Specification & method | Assay basis can differ for the same name | State indices, test method and acceptance rules in the contract |
| Impurities & lot consistency | Trace impurities often explain performance differences | Request impurity profiles and recent COAs; compare key indices |
| Identity check | Same-name, salt-form and hydrate confusion causes dosing errors | Cross-check CAS and InChIKey; confirm by spectroscopy where needed |
| Packaging, storage & retest | Transit conditions change the state on arrival | Check SDS storage and retest date; retain and retest on arrival |
Frequently asked questions
What are the formula, molecular weight and identifiers of Magnesium Hydroxide (CAS 1309-42-8)?
Formula H2MgO2, molecular weight 58.32 g/mol; accurate mass 57.9905210. CAS 1309-42-8 resolves the substance across PubChem and ChemSpider; InChIKey VTHJTEIRLNZDEV-UHFFFAOYSA-L distinguishes same-name substances, salts and hydrates. Use the molecular weight for stoichiometric conversion; purity and grade follow the batch COA.
Is Magnesium Hydroxide suitable for Industrial Chemicals applications, and what should be checked first?
Three checks: (1) the regulatory grade and production licence for the intended use; (2) impurity and safety indices plus test methods on the batch COA; (3) identity via CAS and substance identifiers to rule out hydrate/anhydrous or salt/free-form mix-ups. With limited published property data, determine solubility and addition method by bench testing rather than inference from related materials.
How is the dosage of Magnesium Hydroxide calculated from molecular weight?
At 58.32 g/mol, 1 mol = 58.32 g. Blending, substitution and neutralisation should be calculated on molar equivalence, not by substituting mass parts of a related material. For hydrates or salts, adjust for active content and water of crystallisation from the COA.
What incoming-QC tests apply to Magnesium Hydroxide on arrival?
At minimum: match the COA lot to the goods; retest assay and loss on drying / water; confirm identity via InChIKey VTHJTEIRLNZDEV-UHFFFAOYSA-L or spectroscopy; retain a sample with opening conditions logged. Caking, colour shift or a broad melting range should trigger polymorph and residual-solvent checks.
Related materials
- magnesium 2 4 6 trinitroresorcinolate（CAS 13255-27-1）：shares the 'magnesium' parent fragment — compare formula and molecular weight to identify salt, ester or hydrate form
- magnesium 2 4 pentanedionate dihydrate（CAS 14024-56-7）：shares the 'magnesium' core; before substituting, check the CAS and molecular-weight gap, as salt formation adds a counter-ion
- magnesium 2 methylpropan 2 olate（CAS 32149-57-8）：belongs to the same 'magnesium' series — confirm it is the same CAS; salt and free-form assays are not interchangeable by mass
- magnesium 12 hydroxy stearate（CAS 40277-04-1）：shares the 'magnesium' parent fragment — compare formula and molecular weight to identify salt, ester or hydrate form
- magnesium 2 cation dinitrate（CAS 50908-84-4）：shares the 'magnesium' core; before substituting, check the CAS and molecular-weight gap, as salt formation adds a counter-ion
- magnesium 2 4 8 10 tetraoxa 3 9 diphosphaspiro 5 5 undecane（CAS 97890-21-6）：belongs to the same 'magnesium' series — confirm it is the same CAS; salt and free-form assays are not interchangeable by mass
For side-by-side comparison see site search for Magnesium Hydroxide, or browse the Organic Chemicals directory.
Supply & compliance
Jinan Shenghe Chemical Co., Ltd. supplies industrial and fine chemicals. When enquiring, state the product name, CAS, target grade and packaging; COA, SDS and technical data sheets are available with the shipment. Contact: info@chemsp.cn | +86-18553102138. This page is technical information for industrial raw materials; regulated food, feed, cosmetic or pharmaceutical uses require the corresponding grade and compliance with local rules.
Data sources
Source: PubChem computed properties, CID 73981 (https://pubchem.ncbi.nlm.nih.gov/compound/73981), accessed 2026-11-09; melting/boiling points, where shown, come from the site product page. Hydrates and salts carry different values — verify by CAS and InChIKey.
Related Products
- magnesium 2 4 6 trinitroresorcinolate (CAS 13255-27-1)
- magnesium 2 4 pentanedionate dihydrate (CAS 14024-56-7)
- magnesium 2 methylpropan 2 olate (CAS 32149-57-8)
- magnesium 12 hydroxy stearate (CAS 40277-04-1)
- magnesium 2 cation dinitrate (CAS 50908-84-4)
- magnesium 2 4 8 10 tetraoxa 3 9 diphosphaspiro 5 5 undecane (CAS 97890-21-6)