Phosphide carbides or carbide phosphides are compounds containing anions composed of carbide (C4−) and phosphide (P3−). They can be considered as mixed anion compounds. Related compounds include phosphide silicides, germanide phosphides, arsenide carbides, nitride carbides and silicide carbides.
In light rare earth phosphide carbides, the ethenide ion [C=C]4− exists. In these P and C2 are disordered, and they randomly substitute for each other, even though charge differs. Bonds between carbon and phosphorus are weak, and so these kinds of compounds do not contain a C-P bond, instead carbon or phosphorus stand by themselves.
Phosphide carbides can be made by heating a metal, red phosphorus and graphite powder together in a carbon crucible under an inert gas atmosphere.
List formulasystemspace groupunit cell ÅvolumedensitycommentrefV2PChexagonalP63/mmca=3.077 c=10.91V3PC1-xV4P2CP2ma =9.567,c =3.166V18P9C2orthorhombicPmmaa = 17.044, b = 3.2219, c = 13.030, Z = 2715.55.66Cr3PCorthorhombicCmcma=3.051 b=9.702 c=7.295 Z=42166.16metallicCr8.105P6C0.76Cr8P6CP31ma=6.682 c=4.606Nb2PChexagonalP63/mmca=3.38 c=11.5blackNb3P2ChexagonalP63/mmca=3.3063 c=18.0808 Z=2171.1496.8YRu2PCCmcmZ=4grey; air stableLa4[P0.64(C2)0.36]3cubicI213a=8.9300 Z=4712.1Ce4[P0.66(C2)0.34]3cubicI213a=8.7592 Z=4680.4Pr4[P0.65(C2)0.35]3cubicI213a=8.809 Z=4683.6Nd4[P0.68(C2)0.32]3cubicI213a=8.6763 Z=4653.1CeRu2PCCmcma=3.8896 b=10.9730 c=7.1472 Z=4305.05.05grey; air stableSmRu2PCCmcm3.8278 b=10.9465 c=7.0986 Z=4297.45.32grey; air stableGdRu2PCCmcmZ=4grey; air stableTbRu2PCCmcma=3.7764 b=10.9661 c=7.0504 Z=4292.05.53grey; air stableDyRu2PCCmcmZ=4grey; air stableHoRu2PCCmcmZ=4grey; air stableErRu2PCCmcmZ=4grey; air stableTa3P2ChexagonalP63/mmca=3.2969 c=18.010 Z=2169.53112.1YOs2PCCmcmZ=4grey; air stableCeOs2PCCmcmZ=4grey; air stablePrOs2PCCmcmZ=4grey; air stableNdOs2PCCmcmZ=4grey; air stableSmOs2PCCmcmZ=4grey; air stableGdOs2PCCmcma=3.8274 b=10.8875 c=7.2140 Z=4300.67.73grey; air stableTbOs2PCCmcmZ=4grey; air stable
References