Hydrogen cyanamide 50% SL (CAS 420-04-2, H2NCN, MW 42.04) is the aqueous soluble-liquid form of cyanamide: a colourless to light yellow clear liquid containing 50.0% minimum cyanamide, stabilised at pH 3.8 – 5.4, with dicyandiamide held at 2.0% max. PolyBlueChem supplies it with per-batch COA and SDS. A 95% crystalline grade is also available – specification issued against enquiry.
The active substance is a small, highly polar molecule: two nitrogens in 42 g/mol, 66.6% nitrogen by mass, fully miscible with water. That density of nitrogen is why cyanamide sits upstream of a whole family of products – dicyandiamide, thiourea, guanidines, pharmaceutical and agrochemical intermediates – and why, as a plant growth regulator, it is used to break bud dormancy. The 50% solution is the form most of the world buys, because the anhydrous solid melts at 45 – 46 °C and is far less convenient to store and dose.
Specifications (50% SL)
| Property | Specification |
|---|---|
| Appearance | Colourless or light yellow clear liquid |
| Hydrogen cyanamide content | 50.0% min |
| Dicyandiamide | 2.0% max |
| pH | 3.8 – 5.4 |
| Dilution stability (200 times) | Stable |
| Density (20 °C) | 1.065 – 1.095 g/mL |
| CAS number | 420-04-2 |
| Formula / MW | CH2N2 / 42.04 g/mol |
| PubChem CID | 9864 |
| SMILES | N#CN |
What the specification numbers actually mean
| Item | Reading |
|---|---|
| 50.0% min cyanamide | The assay is the only figure you buy. With the density window it converts to 532 – 548 g of cyanamide per litre, or roughly 12.7 – 13.0 mol/L – use that conversion when you dose by volume rather than by weight. |
| Dicyandiamide 2.0% max | Cyanamide dimerises to dicyandiamide (C2H4N4, MW 84.08 – exactly two cyanamide units). A 2.0% dicyandiamide figure therefore represents about 2.0% of the cyanamide originally charged that has already been lost to dimerisation, and it is the single best indicator of age and storage temperature. |
| pH 3.8 – 5.4 | Not a cosmetic parameter. The solution is deliberately held acidic, because dimerisation to dicyandiamide is fastest in neutral and alkaline solution. A batch that arrives at pH 6 has been buffered wrong or has aged. |
| Dilution stability (200x) | At 200-fold dilution the spray or process liquor contains 0.25% cyanamide. The test confirms that the stabiliser package holds at use dilution, with no haze, precipitation or gassing in the tank. |
| Density 1.065 – 1.095 | A cross-check on the assay: 50% w/w of a solution with this density cannot be much outside the stated window. A density below 1.06 with a 50.0% assay on the COA should be questioned. |
Two forms, two supply chains
| Property | 50% SL (this product) | 95% crystalline |
|---|---|---|
| Physical form | Clear liquid, water-white to light yellow | Crystalline solid (mp 45 – 46 °C) |
| Assay | 50.0% min | 95% grade – specification on enquiry |
| Handling | Pumped and metered as a liquid; needs no melting | Must be kept above its melting point or dissolved on site; hygroscopic and dimerises faster when warm |
| Freight | Water is paid for and shipped | Half the freight per tonne of active, but a much shorter shelf life at ambient temperature |
| Typical use | Agricultural dormancy breaking, on-site industrial reactions, dilute chemistry | Formulators who need high active concentration or a water-free system |
Cost comparisons between the two must be made per tonne of cyanamide, not per tonne of product: 1 tonne of 50% SL carries 500 kg of active, so a 95% crystal has to be priced against roughly 1.9 tonnes of the solution before any handling cost is added.
Where hydrogen cyanamide is used
- Plant growth regulator – bud dormancy breaking. Applied to grapes, kiwifruit, apples, blueberries and stone fruit to synchronise and advance bud break. Application rate and timing are set by the local label and registration, not by the supplier.
- Dicyandiamide manufacture. Controlled dimerisation of cyanamide is the route to dicyandiamide, the latent epoxy curing agent and nitrification inhibitor.
- Thiourea and guanidine chemistry. Addition of H2S gives thiourea; reaction with hydrazine gives aminoguanidine. Both are entry points to pharmaceutical, agrochemical and rubber-chemical value chains.
- Nitrification inhibition. Cyanamide and its dimer are the chemistry behind nitrification-inhibiting nitrogen fertilisers.
- Intermediate for heterocycles and guanylation reagents – the electrophilic carbon is attacked by nucleophiles to give amidines, guanidines and aminotriazines.
Buying notes
- Buy on assay plus dicyandiamide, not on assay alone. Two drums at 50.1% can differ by a factor of two in dicyandiamide, and that difference is age.
- Check the pH band – it tells you whether the stabiliser system is intact.
- Ask for the batch date and treat this as a rotation product. Cyanamide solution does not fail suddenly; it drifts upward in dicyandiamide and downward in assay.
- State the end use. Agricultural use requires a registration in most markets; industrial use does not. The paperwork – and in some destinations the buyer’s eligibility – differs.
- Plan packaging around the hazard: this is a toxic, skin-sensitising liquid and must not be repacked into unlabelled or food-grade containers.
Packaging and supply
Supplied in 25 kg, 200 kg and 1000 kg HDPE drums and IBCs, FOB or CIF against destination, with per-batch COA and current SDS. 95% crystalline cyanamide is available on enquiry – the specification for that grade is issued against the specific request rather than published, so please state the assay, moisture and dicyandiamide limits you need. Store the 50% SL under cover, out of direct sunlight, between 5 and 30 °C, with bungs tight: freezing is not a rupture risk in a plastic drum, but repeated freeze-thaw and summer heat both accelerate dimerisation to dicyandiamide.
Hazard notice: hydrogen cyanamide is toxic if swallowed, harmful in contact with skin, causes serious eye damage and may cause an allergic skin reaction. It also produces a disulfiram-like reaction with alcohol – no alcohol consumption during or after handling until the shift has ended. Wear chemical-resistant gloves, goggles or a face shield and adequate ventilation; do not eat, drink or smoke in the work area. Do not store or dilute with alkaline materials, and keep away from oxidising agents. Refer to the SDS for transport classification, first aid and disposal.
Further reading
- Hydrogen cyanamide (CAS 420-04-2): chemistry, manufacture, 50% SL specification and applications
- Cyanamide 50% SL vs 95% crystalline: grade selection, stability and dosing
- How to buy hydrogen cyanamide 50% SL: documents, packaging and acceptance tests
- Dicyandiamide (CAS 461-58-5): properties, manufacturing and applications – the downstream of cyanamide dimerisation
FAQ
Is 50% SL the same as "liquid cyanamide"?
Yes. SL means soluble liquid: a solution formulation. Hydrogen cyanamide 50% SL, liquid cyanamide and cyanamide 50% solution all refer to the same product – CAS 420-04-2 at 50.0% min in water, acid-stabilised.
Why does the specification limit dicyandiamide?
Because dicyandiamide is the dimerisation product and a direct measure of how much cyanamide has been lost during storage. Two cyanamide molecules give one dicyandiamide molecule of the same mass, so 2.0% dicyandiamide corresponds to about 2.0% of active already lost.
Do you supply the 95% crystalline grade?
Yes, against enquiry. The specification for that grade is issued per request – tell us the assay, moisture and dicyandiamide limits your process needs and we will confirm what can be supplied.
Is hydrogen cyanamide a registered plant protection product?
It is an active substance used as a plant growth regulator, and registration is country-specific. PolyBlueChem supplies the technical material; the buyer is responsible for confirming registration, label and end-use requirements in the destination market.
PolyBlueChem supplies hydrogen cyanamide 50% SL (CAS 420-04-2) at 50.0% min, dicyandiamide 2.0% max, pH 3.8 – 5.4, in 25 kg drums to IBCs with per-batch COA and SDS, and can quote the 95% crystalline grade on request. Tell us the application and the destination, and we will confirm the grade, the packaging and the documentation.
