gradeACS reagentQuality Level200vapor pressure1 mmHg ( 719 °C)Assay≥85%formpelletsimpurities≤0.001% N compounds≤2.0% K2CO310-15% waterpH~13.5 (25 °C, 5.6 g/L)mp361 °C (lit.)anion traceschloride (Cl-): ≤0.01%phosphate (PO43-): ≤5 ppmsulfate (SO42-): ≤0.003%cation tracesCa: ≤0.005%Fe: ≤0.001%Mg: ≤0.002%Na: ≤0.05%Ni: ≤0.001%heavy metals: ≤0.001% (by ICP-OES)