Ca3(PO4)2 + 8 Mg → Ca3P2 + 8 MgO

This is an oxidation-reduction (redox) reaction:

2 PV + 16 e- → 2 P-III (reduction)

8 Mg0 - 16 e- → 8 MgII (oxidation)

Ca3(PO4)2 is an oxidizing agent, Mg is a reducing agent.

Reactants:

  • Ca3(PO4)2 – Tricalcium bis(phosphate) source: wikipedia, accessed: 2019-09-28
    • Other names: Tricalcium phosphate source: wikipedia, accessed: 2019-09-28source: wikidata, accessed: 2019-09-02, Tribasic calcium phosphate source: wikipedia, accessed: 2019-09-28source: wikidata, accessed: 2019-09-02, Bone phosphate of lime source: wikidata, accessed: 2019-09-02
    • Appearance: White amorphous powder source: wikipedia, accessed: 2019-09-28
  • Mg
    • Names: Magnesium source: wikidata, accessed: 2019-09-07, Magnesium (powder) source: ICSC, accessed: 2019-09-04, Magnesium (pellets) source: ICSC, accessed: 2019-09-04
    • Appearance: Grey powder source: ICSC, accessed: 2019-09-04; Silvery-white metallic solid in various forms source: ICSC, accessed: 2019-09-04

Products:

  • Ca3P2 – Calcium phosphide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Photophor source: wikipedia, accessed: 2019-09-27, CP source: wikipedia, accessed: 2019-09-27, Polythanol source: wikipedia, accessed: 2019-09-27, Tricalcium diphosphide source: wikidata, accessed: 2019-09-02
    • Appearance: Red-brown crystalline powder or grey lumps source: wikipedia, accessed: 2019-09-27; Red-brown crystalline powder or grey lumps source: ICSC, accessed: 2019-09-04
  • MgO – Magnesium oxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Magnesia source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Periclase source: wikipedia, accessed: 2019-09-27, Magnesium oxide fume source: NIOSH NPG, accessed: 2019-09-02
    • Appearance: White powder source: wikipedia, accessed: 2019-09-27; Hygroscopic fine white powder source: ICSC, accessed: 2019-09-04; Finely divided white particulate dispersed in air. [Note: Exposure may occur when magnesium is burned, thermally cut, or welded upon.] source: NIOSH NPG, accessed: 2019-09-02