(define (read-xyz)
  (let ((natoms (read))                 ; number of atoms
        (rest-of-line (read-line))      ; discard the rest of the line
        (comment-line (read-line)))     ; any text
    (let loop ((n natoms)
               (acc '()))
      (if (zero? n)
          ;; (list natoms rest-of-line comment (reverse acc))
          (list natoms comment-line (reverse acc))
          (let ((symbol (read))
                (x (read))
                (y (read))
                (z (read)))
            (loop (- n 1)
                  (cons (list symbol (list x y z)) acc)))))))

15
This is uranyl with some waters
U      -0.414633333333333      0.213933333333333      0.048566666666667
O       1.186425751635119      0.980622195189284      0.121046706417034
O      -2.015692418301786     -0.552755528522618     -0.023913373083700
O      -1.400296137734070      2.330651998063650     -0.474962349653488
H      -2.374231172314353      2.490621981130683     -0.635773272586715
H      -0.901393783370848      3.192476432338561     -0.566368505340978
O       0.580464534891958     -1.904327988632390      0.553410186515704
H       0.085625448774497     -2.768968442594905      0.640192467091476
H       1.556649317569456     -2.062595989295014      0.701783061513602
O      -0.109385653277192     -0.209486930054325     -2.286303549628824
H      -0.768228170218269     -0.667146175042155     -2.883358449405985
H       0.699067364115980      0.046446395180368     -2.816305296514802
O      -0.722212952773571      0.638425892167969      2.384031196221085
H      -1.532165379339123      0.390423939301528      2.915512238286563
H      -0.057700948432124      1.089330366457678      2.979941383373171