IUPAC Name: dichloromercury; tris(4-chlorophenyl)phosphane 
Molecular Formula: C₃₆H₂₄Cl₈HgP₂
Molecular Weigh: 1002.737282g/mol
H-Bond Donor: 0
H-Bond Acceptor: 0
Rotatable Bond Count: 6
Exact Mass: 1003.850871
MonoIsotopic Mass: 999.856771
Topological Polar Surface Area: 0
Heavy Atom Count: 47
Formal Charge: 0
Complexity: 278
Canonical SMILES: C1=CC(=CC=C1P(C2=CC=C(C=C2)Cl)C3=CC=C(C=C3)Cl)Cl.C1=CC(=CC=C1P(C2=CC=C
(C=C2)Cl)C3=CC=C(C=C3)Cl)Cl.Cl[Hg]Cl
InChI: InChI=1S/2C18H12Cl3P.2ClH.Hg/c2*19-13-1-7-16(8-2-13)22(17-9-3-14(20)4-10-17)18-11-5-15(21)6-12-18;;;/h2*1-12H;2*1H;/q;;;;+2/p-2
InChIKey: VLMAPEVJDNNONK-UHFFFAOYSA-L
Structure of Bis(tris(p-chlorophenyl)phosphine)mercuric chloride complex (CAS NO.74039-78-4):

 

Mercury and its compounds are on the Community Right-To-Know List.

Poison by intravenous route. See also MERCURY COMPOUNDS, INORGANIC; MERCURY COMPOUNDS, ORGANIC and CHLORIDES. When heated to decomposition it emits very toxic fumes of Cl⁻, PO_x and Hg.

OSHA PEL: CL 0.1 mg(Hg)/m³ (skin)
ACGIH TLV: TWA 0.1 mg(Hg)/m³ (skin); BEI: 35 µg/g creatinine total inorganic mercury in urine preshift; 15 µg/g creatinine total inorganic mercury in blood at end of shift at end of workweek.
DFG MAK: Confirmed Animal Carcinogen with Unknown Relevance to Humans
NIOSH REL: (Mercury, Aryl and Inorganic) CL 0.1 mg/m³ (skin)

  Bis(tris(p-chlorophenyl)phosphine)mercuric chloride complex , its cas register number is 74039-78-4. It also can be called NSC 226749 ; Phosphine, tris(p-chlorophenyl)- , complex with mercuric chloride ; Mercury, dichlorobis(tris(4-chlorophenyl)phosphine)-, (T-4)-(9CI) ; Phosphine, tris(p-chlorophenyl)-, complex with mercuric chloride (2:1) .When heated to decomposition it emits very toxic fumes of Cl⁻, PO_x and Hg.  The storage environment of Bis(tris(p-chlorophenyl)phosphine)mercuric chloride complex (CAS NO.74039-78-4) should be ventilate, low-temperature and dry. And keep away with oxidant and acid.