Solubility Rules — Cation to Anion Reference¶
状态: ✅ 已完成
创建日期: 2026-03-08 最后更新: 2026-03-08
Based on the standard solubility table (SOLUBILITY OF COMMON COMPOUNDS IN WATER, > 0.1 mol/L at 25°C), reorganized from the cation (positive ion) perspective.
Quick-Lookup Table¶
| Cation | Soluble Anions | Low Solubility Anions |
|---|---|---|
| Alkali ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Fr⁺) | ALL | — |
| H⁺ | ALL | — |
| NH₄⁺ | ALL | — |
| Be²⁺ | NO₃⁻, Cl⁻, Br⁻, I⁻, SO₄²⁻, S²⁻ | OH⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
| Mg²⁺ | NO₃⁻, Cl⁻, Br⁻, I⁻, SO₄²⁻, S²⁻ | OH⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
| Ca²⁺ | NO₃⁻, Cl⁻, Br⁻, I⁻, S²⁻ | SO₄²⁻, OH⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
| Sr²⁺ | NO₃⁻, Cl⁻, Br⁻, I⁻, S²⁻, OH⁻ | SO₄²⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
| Ba²⁺ | NO₃⁻, Cl⁻, Br⁻, I⁻, S²⁻ | SO₄²⁻, OH⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
| Ag⁺ | NO₃⁻ | Cl⁻, Br⁻, I⁻, SO₄²⁻, S²⁻, OH⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
| Pb²⁺ | NO₃⁻ | Cl⁻, Br⁻, I⁻, SO₄²⁻, S²⁻, OH⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
| Cu⁺ | NO₃⁻, SO₄²⁻ | Cl⁻, Br⁻, I⁻, S²⁻, OH⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
| All other cations (e.g. Fe²⁺, Fe³⁺, Cu²⁺, Zn²⁺, Al³⁺, Ni²⁺, Co²⁺, Mn²⁺, Cr³⁺ …) | NO₃⁻, Cl⁻, Br⁻, I⁻, SO₄²⁻ | S²⁻, OH⁻, PO₄³⁻, CO₃²⁻, SO₃²⁻ |
Detailed Rules (by Cation)¶
Always Soluble — No Exceptions¶
| Cation | Rule |
|---|---|
| Alkali ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Fr⁺) | Soluble with ALL anions |
| H⁺ | Soluble with ALL anions |
| NH₄⁺ | Soluble with ALL anions |
Alkaline Earth Metals — Mixed Solubility¶
Be²⁺ / Mg²⁺
| Anion | Solubility |
|---|---|
| NO₃⁻ | Soluble |
| Cl⁻, Br⁻, I⁻ | Soluble |
| SO₄²⁻ | Soluble |
| S²⁻ | Soluble |
| OH⁻ | Low Solubility |
| PO₄³⁻, CO₃²⁻, SO₃²⁻ | Low Solubility |
Ca²⁺
| Anion | Solubility |
|---|---|
| NO₃⁻ | Soluble |
| Cl⁻, Br⁻, I⁻ | Soluble |
| SO₄²⁻ | Low Solubility |
| S²⁻ | Soluble |
| OH⁻ | Low Solubility |
| PO₄³⁻, CO₃²⁻, SO₃²⁻ | Low Solubility |
Sr²⁺
| Anion | Solubility |
|---|---|
| NO₃⁻ | Soluble |
| Cl⁻, Br⁻, I⁻ | Soluble |
| SO₄²⁻ | Low Solubility |
| S²⁻ | Soluble |
| OH⁻ | Soluble |
| PO₄³⁻, CO₃²⁻, SO₃²⁻ | Low Solubility |
Ba²⁺
| Anion | Solubility |
|---|---|
| NO₃⁻ | Soluble |
| Cl⁻, Br⁻, I⁻ | Soluble |
| SO₄²⁻ | Low Solubility |
| S²⁻ | Soluble |
| OH⁻ | Low Solubility |
| PO₄³⁻, CO₃²⁻, SO₃²⁻ | Low Solubility |
Transition / Heavy Metals — Most Restricted¶
Ag⁺
| Anion | Solubility |
|---|---|
| NO₃⁻ | Soluble |
| Cl⁻, Br⁻, I⁻ | Low Solubility |
| SO₄²⁻ | Low Solubility |
| S²⁻ | Low Solubility |
| OH⁻ | Low Solubility |
| PO₄³⁻, CO₃²⁻, SO₃²⁻ | Low Solubility |
Pb²⁺
| Anion | Solubility |
|---|---|
| NO₃⁻ | Soluble |
| Cl⁻, Br⁻, I⁻ | Low Solubility |
| SO₄²⁻ | Low Solubility |
| S²⁻ | Low Solubility |
| OH⁻ | Low Solubility |
| PO₄³⁻, CO₃²⁻, SO₃²⁻ | Low Solubility |
Cu⁺
| Anion | Solubility |
|---|---|
| NO₃⁻ | Soluble |
| Cl⁻, Br⁻, I⁻ | Low Solubility |
| SO₄²⁻ | Soluble |
| S²⁻ | Low Solubility |
| OH⁻ | Low Solubility |
| PO₄³⁻, CO₃²⁻, SO₃²⁻ | Low Solubility |
All Other Cations (Fe²⁺, Fe³⁺, Cu²⁺, Zn²⁺, Al³⁺, Ni²⁺, Co²⁺, Mn²⁺, Cr³⁺ …)¶
| Anion | Solubility |
|---|---|
| NO₃⁻ | Soluble |
| Cl⁻, Br⁻, I⁻ | Soluble |
| SO₄²⁻ | Soluble |
| S²⁻ | Low Solubility |
| OH⁻ | Low Solubility |
| PO₄³⁻, CO₃²⁻, SO₃²⁻ | Low Solubility |
Memory Aid¶
从正离子角度记忆：
- 碱金属、H⁺、NH₄⁺ → 万能溶，配什么阴离子都溶
- NO₃⁻（硝酸盐） → 万能溶，配什么阳离子都溶
- Ag⁺ 和 Pb²⁺ → 最难溶，只有 NO₃⁻ 能救
- Ca²⁺、Sr²⁺、Ba²⁺ → 小心 SO₄²⁻（硫酸盐不溶）
- Sr²⁺ 是唯一让 OH⁻ 溶的非碱金属/H⁺/NH₄⁺ 阳离子
- 普通过渡金属 → 卤化物和硫酸盐溶，硫化物/氢氧化物/磷酸盐/碳酸盐/亚硫酸盐不溶