Potassium fertilizer is not a single compound, but a general term for fertilizers whose main nutrient is potassium (K).
The following are the structural characteristics of several common potassium fertilizers:
1. Potassium Chloride (KCl)
Chemical Structure: Ionic crystal, composed of potassium ions (K⁺) and chloride ions (Cl⁻).
Physical Properties: White or pale yellow crystals; Easily soluble in water (solubility 34.7% at 20℃); Low hygroscopicity, does not easily clump; Contains approximately 50%–60% potassium oxide (K₂O).
2. Potassium Sulfate (K₂SO₄)
Chemical Structure: Ionic crystal, containing two potassium ions (K⁺) and one sulfate ion (SO₄²⁻).
Physical properties: White or grayish-white crystals; Contains approximately 48%–52% potassium oxide; Low hygroscopicity, does not easily clump; Aqueous solution is weakly acidic (physiologically acidic fertilizer).
3. Potassium nitrate (KNO₃)
Chemical structure: Ionic compound, composed of potassium ions (K⁺) and nitrate ions (NO₃⁻).
Physical properties: Colorless, transparent prismatic crystals or white powder; Contains approximately 46% potassium oxide and approximately 13.5% nitrate nitrogen; Easily soluble in water, moderately hygroscopic, easily clumps;
