calcium dichloride tetra urea was prepared by the reaction of calcium chloride with urea in aqueous solution. the crystals are monoclinic, a= 7.633, b= 12.45 1, c= 8.118 ?,? = 113.17, z = 4, space group p 2,/a. the crystal structure was determined by single crystal x-ray methods and refined to r= 0.041. the calcium atoms are coordinated to four oxygen atoms of urea and to two chloride ions. the...