Oxyphosphides

Oxyphosphides are chemical compounds formally containing the group PO, with one phosphorus and one oxygen atom. The phosphorus and oxygen are not bound together as in phosphates or phosphine oxides, instead they are bound separately to the cations (metals), and could be considered as a mixed phosphide-oxide compound. So a compound with OmPn requires cations to balance a negative charge of 2m+3n. The cations will have charges of +2 or +3. The trications are often rare earth elements or actinides. They are in the category of oxy-pnictide compounds.

Many compounds are layered, containing two metals with the formula XZPO, with an XP layer alternating with a ZO layer.

Examples
Examples include


 * Ca4P2O greenish gold, has space group I4mmm Z=2 and unit cell parameters a = 4.492, c = 15.087.
 * Uranium–Copper Oxyphosphide UCuPO semimetallic antiferromagnetic tetragonal ZrCuSiAs-type a =3:7958 c=8:2456 V=118.80 Z=2 MW=348.55 density=9.743
 * Thorium–Copper Oxyphosphide ThCuPO semimetallic tetragonal ZrCuSiAs-type a=3.8995 c=8.2939 V=126.12 Z=2 MW=342.56 density=9.02.
 * NpCuOP
 * Sr2ScCoPO3 high thermoelectric effect
 * Sr2ScFePO3 superconducting 17K.
 * LaNiOP Lanthanum nickel oxyphosphide
 * YOFeP
 * YOMnP
 * YOCdP
 * ROTPn (R = La, Nd, Sm, Gd; T = Mn, Fe, Co, Ni, Cu; Pn = P, As, Sb)
 * YZnPO transparent red R$\overline{3}$m Z=6 a = 3.946, c = 30.71
 * LaZnPO transparent red ZrCuSiAs type
 * DyZnPO transparent red R$\overline{3}$m Z=6 a=3.8933 c=30.305
 * PrZnPO transparent red dimorphic
 * SmZnPO transparent red R$\overline{3}$m Z=6 a = 3.946, c = 30.71
 * NdZnPO transparent a = 3.885 c = 30.32
 * GdZnPO transparent red R$\overline{3}$m Z=6 a=3.922, c = 30.56
 * CeZnPO transparent
 * HoZnPO transparent dark red
 * CeRuPO ferromagnetic below 15K. dimorphic
 * CeOsPO antiferromagnetic

related phosphide oxides

 * La2AuP2O C2/m, a=15.373 b=4.274 c=10.092 β=131.02 V=500.3 dark-red-violet
 * Ce2AuP2O C2/m, a = 15.152, b = 4.2463, c = 9.992 pm, β = 130.90° dark-red-violet
 * Pr2AuP2O C2/m, a = 15.036, b = 4.228, c = 9.930 pm, β = 130.88(2)° dark-red-violet
 * Nd2AuP2O C2/m, a = 15.0187, b = 4.2085, c = 9.903 pm, β = 131.12(1)° dark-red-violet

Oxy-pnictides
Related compounds are the oxybismuthides and oxyarsenides.