Four heterometallic carbonyl complexes: (1) Cp(CO)2MnPt(μ-C=CHPh)dppm) (2) [Cp(CO)2MnCu(μ-C=CHPh)(μ-Cl)]2, (3) CpMnFe2(μ3-C=CHPh)(CO)8, and (4) η4-[Cp(CO)2MnC(CO)CHPh]Fe(CO)3 have been studied by X-ray powder diffraction and their unit cell parameters are reported. Orthorhombic cell parameters for complex (1) are a=18.5719(14) Å, b=18.6092(14) Å, c=23.8117(18) Å, Z=8, space group Pbca. Monoclinic cell parameters found for complex (2) are a=11.5816(5) Å, b=7.9784(5) Å, c=16.7819(7) Å, β=105.460(2)°, Z=2, space group P21∕n. Orthorhombic cell parameters for complex (3) are a=13.5260(9) Å, b=15.1487(10) Å, c=10.3330(6) Å, Z=4, space group Pna21. Monoclinic cell parameters for complex (4) are a=10.3545(45) Å, b=8.0002(43) Å, c=21.8355(95) Å, β=102.89(2), Z=4, space group P21∕c. Parameters found for complexes (1–4) are in good agreement with those obtained from single crystal X-ray diffractometry.