Cannot read property 'errors' of undefined in angular 2

I am validating my template using angular2 but mean while it shows the error

Cannot read the property 'errors' of undefined.

Here is my template.......

   <h3 class = "head">{{title}}</h3>
  <form  [ngFormModel]="form" #f="ngForm">
  <div class="row">
   <div class="form-group">     
  <label class="formHeading">Facebook</label>
  <input type="text" id="facebook" class="form-control col-xs-3"  ngControl="facebook" #facebook="ngForm" >  
   </div>
      <div *ngIf ="facebook.touched  && facebok.errors">  
     <div class="form-row btn">
      <button type="submit" class="btn btn-primary pull-right butspace" [disabled]="!f.valid">Save</button>
 </div>
 </div>
 </form>

I dont know why it shows error,can anyone fix it