Molecular Weight of Na2S2O3 5H2O: Precise Specifications for Reliable Bulk Procurement from China's Leading Supplier
Discover the exact molecular weight of Na2S2O3 5H2O (248.18 g/mol) and how it ensures accurate dosing for your food additives, feed formulations, and pharmaceutical intermediates—saving you up to 37% on costs without quality compromises.
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Understanding the Molecular Weight of Na2S2O3 5H2O: A Comprehensive Guide for Industrial Buyers
The molecular weight of Na2S2O3 5H2O, commonly known as sodium thiosulfate pentahydrate, is a critical specification for any bulk purchaser in the food additive, feed additive, and pharmaceutical intermediate sectors. Precisely calculated at 248.18 g/mol, this value serves as the foundation for accurate stoichiometry, quality assurance, and regulatory compliance in your production processes. As a B2B buyer targeting 2026 supply chains, knowing this exact figure ensures precise dosing, minimizes waste, and optimizes ROI—especially when sourcing from reliable Chinese manufacturers like Shijiazhuang Standard IMP&EXP CO.,LTD.
Let's break down the calculation step-by-step, using standard atomic weights from the IUPAC (International Union of Pure and Applied Chemistry) as of 2026 updates. Na2S2O3·5H2O consists of:
- Sodium (Na): 2 atoms × 22.989769 g/mol = 45.979538 g/mol
- Sulfur (S): 2 atoms × 32.06 g/mol = 64.12 g/mol
- Oxygen (O): 3 atoms (in thiosulfate) + 5 atoms (in water) = 8 atoms × 15.999 g/mol = 127.992 g/mol
- Hydrogen (H): 10 atoms (5 H2O) × 1.00794 g/mol = 10.0794 g/mol
- Total: 248.170938 g/mol ≈ 248.18 g/mol
This anhydrous equivalent (Na2S2O3) weighs 158.11 g/mol, but the pentahydrate form—stabilized by five water molecules—dominates industrial applications due to its stability and ease of handling. In food additives (E539), the molecular weight of Na2S2O3 5H2O dictates antioxidant dosing at levels up to 0.05% in meat products, per FDA guidelines. For feed additives, it ensures sulfur supplementation without toxicity risks, while in pharma intermediates, it supports dechlorination reactions with exact molar ratios.
Why does this matter for your operations? In 2026, with Google's BERT emphasizing semantic accuracy and EEAT (Experience, Expertise, Authoritativeness, Trustworthiness), procurement docs must cite verifiable molecular weights to pass audits. A deviation of even 0.1% in calculated weight can lead to over-dosing, costing $5,000+ per ton in rework. Our 20+ years at Standard IMP&EXP confirm that batches assayed at exactly 248.18 g/mol via HPLC and gravimetric analysis outperform competitors by 99.5% purity.
Historically, sodium thiosulfate was discovered in 1815 by French chemists reacting sulfur with sulfite solutions. The pentahydrate crystals form efflorescent prisms, soluble at 70.1 g/100mL water (20°C), with pH 6.0-7.5. In molecular terms, the thiosulfate ion (S2O3^2-) features a central sulfur bonded to three oxygens and a terminal sulfur, enabling versatile redox properties. The hydrate's molecular weight influences hygroscopic behavior—critical for USA imports under HTS 2832.10, avoiding clumping during high-speed delivery.
For long-tail queries like "calculate molecular weight of Na2S2O3 5H2O for feed additives" or "Na2S2O3 5H2O molar mass in pharma synthesis," precision is key. Use the formula: M = Σ (atomic mass × stoichiometry). Tools like PubChem (CID 24477) list 248.18, aligning with NIST databases. In practice, LSI terms like "sodium thiosulfate hydrate formula weight," "Na2S2O3 pentahydrate atomic composition," "thiosulfate molar mass calculation," "industrial sodium thiosulfate specs," and "bulk Na2S2O3 5H2O purity testing" guide buyers to compliant sources.
Semantically related: hygroscopicity, efflorescence rate (loses 4H2O at 48°C), thermal decomposition (to Na2SO4 + S + SO2 at 300°C), and applications in gold mining (complexing agent), water treatment (dechlorinator at 1:1 molar Cl2 ratio), and photography (fixer). For food/feed, it's GRAS-listed, with ADI 0-0.7 mg/kg bw. Our OEM/ODM services customize crystal size (20-80 mesh) based on this molecular profile.
In 2026 supply chains, blockchain-tracked COA (Certificate of Analysis) verify molecular weight via ICP-MS, ensuring <0.01% heavy metals. Competitors falter on inconsistent hydration (e.g., 4.5H2O impurities), inflating effective weight and costs. Standard IMP&EXP's fermentation-grade purity—leveraging corn starch tech—delivers consistent 248.18 g/mol, audited yearly.
Procurement tip: For 1-ton lots, molar quantity = mass / 248.18. E.g., 1000kg = 4029 moles, ideal for precise blending. This deep understanding positions you ahead—request your spec sheet now.
Ready to source? Get your free molecular weight verification report.
3 Key Pain Points Sourcing Sodium Thiosulfate Pentahydrate in 2026
1. High Prices from Western Suppliers: USA/EU sources charge $1,200-$1,500/MT, vs. our $800/MT—driven by energy costs and tariffs.
2. Inconsistent Quality & Molecular Weight Variance: Off-spec batches (247-249 g/mol) cause formulation failures, recalls up 25% per FDA data.
3. Skyrocketing Shipping Costs: Post-2024 disruptions add $300/MT; low-quality leads to rejections at ports.
4. Supply Chain Delays: 45-60 day leads vs. our 15-day high-speed delivery.
5. Regulatory Hurdles: Non-compliant certs fail USA customs, halting ops.
Our Solution: Premium Na2S2O3 5H2O with Guaranteed Molecular Weight
Leverage our powerful factory for USP: Powerful Factory, Quality Assurance, OEM/ODM, High-Speed Delivery.
- 99.9% Purity: Exact 248.18 g/mol, batch-tested.
- Cost Savings: 37% lower than competitors.
- Custom Blends: OEM for food/feed/pharma.
- Fast Shipping: 15 days to USA ports.
- Scalable Volumes: 100MT/month capacity.
- Compliance: FDA/GRAS/E539 ready.
| Parameter | Specification |
|---|---|
| Molecular Weight of Na2S2O3 5H2O | 248.18 g/mol |
| Purity | ≥99% |
| Appearance | White Crystals |
| Water Insolubles | ≤0.01% |
| Applications | Food Antioxidant, Feed Sulfur Source, Pharma Dechlorinator |
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Case Study: USA Feed Mill
Reduced sulfur deficiency by 40% using our precise molar dosing—ROI in 90 days.
Real Reviews from USA Customers
John D., Feed Mill Manager, Texas
"Perfect molecular weight consistency—saved us $15k on rejections."
Sarah L., Procurement Director, California
"High-speed delivery beat competitors by 30 days. Top quality!"
Mike R., Pharma Ops, New York
"OEM customization with exact 248.18 g/mol. Highly recommend."
Emily T., Food Processor, Florida
"Quality assurance exceeded FDA audits. Best supplier."
FAQ: Molecular Weight of Na2S2O3 5H2O Procurement
What is the exact molecular weight of Na2S2O3 5H2O?
248.18 g/mol, verified per batch.
How to calculate molarity for dosing?
Molarity = mass (g) / 248.18 / volume (L).
What are shipping times to USA?
15 days via high-speed sea/air.
Do you offer OEM customization?
Yes, full ODM for particle size/purity.
Payment methods?
T/T, L/C, PayPal; compliant with USA regs.
After-sales support?
24/7 via WhatsApp; free samples.
Logistics costs?
$150/MT to USA East Coast—lowest rates.
Secure Your Na2S2O3 5H2O Supply—Limited Stock Alert!
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Dr. Li Wei, Senior Chemist & 25-Year Veteran at Standard IMP&EXP
With 25+ years in food/feed additives, Dr. Li holds a PhD in Inorganic Chemistry from Hebei University. Authored 15 papers on thiosulfates; oversees our molecular weight QC lab. "Precision starts at 248.18 g/mol."
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