Calcium Chloride Anhydrous vs Dihydrate for Industrial Use
A calcium chloride purchasing specification must state the chemical form and the basis used for process dosing. The current catalogue lists calcium chloride (CAS 10043-52-4) and calcium chloride dihydrate (CAS 10035-04-8) as separate records. Water of crystallization makes a same-mass substitution unsafe to assume; the offered grade and actual lot still need TDS and COA confirmation.
Compare on the same assay and water basis
Anhydrous calcium chloride is the CaCl₂ form; the dihydrate is CaCl₂·2H₂O. This distinction is chemical identity, not a purity claim about material on offer. If a process specification is expressed as calcium chloride concentration, calculate the required charge using the documented assay basis for the candidate grade. Ask which test method and acceptance limits the supplier will use. Do not infer drying capacity, dissolution time or process yield from the name alone.
| Buyer check | Anhydrous grade | Dihydrate grade | Evidence to obtain |
|---|---|---|---|
| Chemical identity | Specify CaCl₂ without crystallization water; verify supplied grade. | Specify CaCl₂·2H₂O; verify supplied grade. | Current TDS and batch COA; reconcile name and CAS. |
| Assay and water basis | Ask how calcium chloride content and residual water are reported. | Ask how the dihydrate assay and water basis are reported. | Comparable assay basis, method and acceptance range for each quote. |
| Process charge | Calculate against the required calcium chloride concentration. | Recalculate the charge on the documented assay basis. | Buyer process calculation and representative pilot results; no automatic 1:1 swap. |
| Physical handling | Confirm offered particle form and handling constraints. | Confirm offered particle form and handling constraints. | Sample, current SDS, storage instructions and receiving test plan. |
| Commercial comparison | Quote the exact grade and quantity requested. | Quote the exact grade and quantity requested. | Same application, delivered destination and agreed documentation. |
Verify the offered grade in a representative trial
Before changing the purchasing specification, compare samples under the actual dosing and handling conditions. Record the target concentration, addition sequence, relevant temperature and moisture conditions, dissolution or handling observations, and the result against the incumbent material. Agree acceptance criteria with the plant and quality teams. The catalogue establishes that both product families are listed; it does not provide a site-specific substitution approval.
RFQ checklist for anhydrous and dihydrate grades
Send the application, process conditions, required chemical form, assay/water basis, particle form, trial or batch quantity, annual demand, destination and required TDS/SDS/COA through the MOS Group inquiry form. Reference the exact anhydrous product record or dihydrate product record you want quoted, and ask the supplier to confirm the grade and available documents before a plant trial.
FAQ
Can calcium chloride dihydrate replace an anhydrous grade at the same mass?
Do not assume a 1:1 change. The dihydrate has water of crystallization, and the actual supplied assays must be checked. Recalculate on the intended calcium chloride basis and validate in the real process.
Which documents matter when comparing quoted grades?
Request the current TDS, SDS and batch COA for each offered grade. Confirm chemical form, assay and water basis, particle form, test methods and the buyer’s acceptance limits.
Does the catalogue CAS number confirm a usable industrial grade?
No. CAS 10043-52-4 identifies calcium chloride and CAS 10035-04-8 identifies the dihydrate in the current catalogue. They do not establish purity, physical form or process suitability for a particular offered lot.
What should an industrial buyer send with the RFQ?
Give the application and process conditions, required chemical form, assay/water basis, particle form, batch or trial quantity, annual demand, destination and required TDS/SDS/COA. Ask the supplier to confirm the offered grade before testing.
Sources
- Calcium chloride compound record — PubChem, NIH
- Calcium chloride dihydrate compound record — PubChem, NIH
- MOS Group calcium chloride catalogue — MOS Group
- MOS Group calcium chloride dihydrate catalogue — MOS Group
Sources checked on July 26, 2026.
