一、房地产分离出卖,合同无效由于房屋是建筑在土地上的,为土地的附着物,具有不可分离性,因此房屋所有权通过买卖而转让时,该房屋占用范围内的土地使用权也必须同时转让。如果卖方将房地产和土地分别卖于不同的买方,或者出卖房屋时只转让房屋所有权而不同时转让土地使用权,买方可以提出这种买卖合同无效。二、产权主体有问题,合同无效出卖房屋的主体必须是该房屋的所有权人。非所有权人出卖他人的房屋时,须提交共有人的同意证明书。部分共有人未取得其他共有人同意,擅自出 First, the separation of real estate sold, the contract is invalid As the housing is built on the land, for the attachment of the land, inseparable, so the ownership of the house through the sale and transfer, the land use rights within the area occupied by the housing must also be transferred at the same time . If the seller sells property and land separately to different buyers or sells the house only to transfer the ownership of the property without transferring the land use right at the same time, the buyer may claim that the sale and purchase contract is invalid. Second, there are problems with the subject of property rights, the contract is invalid The subject of the betrayed house must be the owner of the house. When the non-owner betrays another’s house, a certificate of consent of the co-owner shall be submitted. Some of the co-owners did not get the consent of other co-owners