The crystal structure and mechanism of the title molecule are discribed. Thiscrystal is orthorhombic, belonging to space group PC21/B with α=1. 002 1 (2) nm, b=1. 483 0(3) nm, c=2. 173 6(4) nm, V=3. 230 39(2) nm3, Z=2, Dc=1.80 g/cm3, R=0. 069 3. The structure was solved by direct method. The tin atom of the title compoundexists in two distorted-trigonal-bipyramidal geometry, defined by two carbon, one bromide,one chloride and one oxygen atoms leading to a five-membered chelate ring. In the structure,the five-membered ring containing the intermolecular O→Sn has a half chair conformation. This crystal structure and mechanism of the title molecule are discribed. This crystal is orthorhombic, belonging to space group PC21 / B with α = 1. 002 1 (2) nm, b = 1.483 0 (3) nm, c = 2. 173 6 (4) nm, V = 3. 230 39 (2) nm3, Z = 2, Dc = 1.80 g / cm3, R = 0 069 3. The structure of the tin atom of the title In the structure, the five-membered ring contains the intermolecular O → Sn has a half chair conformation.